ASPEN INSURANCE HOLDINGS LTD AHL-PE Financial Statement Data

2025 Q2

Submissions

Field	Row 1	Row 2
adsh	0001628280-25-020465	0001628280-25-020463
cik	1267395	1267395
name	ASPEN INSURANCE HOLDINGS LTD	ASPEN INSURANCE HOLDINGS LTD
sic	6331	6331
countryba	BM	BM
stprba
cityba	HAMILTON	HAMILTON
zipba	HM 19	HM 19
bas1	141 FRONT STREET	141 FRONT STREET
bas2
baph	1 441 297 9301	1 441 297 9301
countryma	BM	BM
stprma
cityma	HAMILTON	HAMILTON
zipma	HM 19	HM 19
mas1	141 FRONT STREET	141 FRONT STREET
mas2
countryinc	BM	BM
stprinc
ein	000000000	000000000
former
changed
afs	4-NON	4-NON
wksi	0	0
fye	1231	1231
form	6-K	F-1/A
period	20241231	20241231
fy
fp
filed	20250429	20250429
accepted	2025-04-29 06:55:00.0	2025-04-29 06:49:00.0
prevrpt	0	0
detail	1	1
instance	ahl-20241231_htm.xml	ahl-20250429_htm.xml
nciks	1	1
aciks

Description

Field Name	Field Description
adsh	Accession Number. The 20-character string formed from the 18-digit number assigned by the SEC to each EDGAR submission.
cik	Central Index Key (CIK). Ten digit number assigned by the SEC to each registrant that submits filings.
name	Name of registrant. This corresponds to the name of the legal entity as recorded in EDGAR as of the filing date.
sic	Standard Industrial Classification (SIC). Four digit code assigned by the SEC as of the filing date, indicating the registrant’s type of business.
countryba	The ISO 3166-1 country of the registrant's business address.
stprba	The state or province of the registrant’s business address, if field countryba is US or CA.
cityba	The city of the registrant's business address.
zipba	The zip code of the registrant’s business address.
bas1	The first line of the street of the registrant’s business address.
bas2	The second line of the street of the registrant’s business address.
baph	The phone number of the registrant’s business address.
countryma	The ISO 3166-1 country of the registrant's mailing address.
stprma	The state or province of the registrant’s mailing address, if field countryma is US or CA.
cityma	The city of the registrant's mailing address.
zipma	The zip code of the registrant’s mailing address.
mas1	The first line of the street of the registrant’s mailing address.
mas2	The second line of the street of the registrant’s mailing address.
countryinc	The ISO 3166-1 country of incorporation for the registrant.
stprinc	The state or province of incorporation for the registrant, if countryinc is US or CA.
ein	Employee Identification Number, 9 digit identification number assigned by the Internal Revenue Service to business entities operating in the United States.
former	Most recent former name of the registrant, if any.
changed	Date of change from the former name, if any.
afs	Filer status with the SEC at the time of submission: 1-LAF=Large Accelerated, 2-ACC=Accelerated, 3-SRA=Smaller Reporting Accelerated, 4-NON=Non-Accelerated, 5-SML=Smaller Reporting Filer, NULL=not assigned.
wksi	Well Known Seasoned Issuer (WKSI). An issuer that meets specific SEC requirements at some point during a 60-day period preceding the date the issuer satisfies its obligation to update its shelf registration statement.
fye	Fiscal Year End Date, rounded to nearest month-end.
form	The submission type of the registrant’s filing.
period	Balance Sheet Date, rounded to nearest month-end.
fy	Fiscal Year Focus (as defined in the EDGAR XBRL Guide Ch. 3.1.8).
fp	Fiscal Period Focus (as defined in the EDGAR XBRL Guide Ch. 3.1.8) within Fiscal Year.
filed	The date of the registrant’s filing with the Commission.
accepted	The acceptance date and time of the registrant’s filing with the Commission.
prevrpt	Previous Report – TRUE indicates that the submission information was subsequently amended.
detail	TRUE indicates that the XBRL submission contains quantitative disclosures within the footnotes and schedules at the required detail level (e.g., each amount).
instance	The name of the submitted XBRL Instance Document. The name often begins with the company ticker symbol.
nciks	Number of Central Index Keys (CIK) of registrants (i.e., business units) included in the consolidating entity’s submitted filing.
aciks	Additional CIKs of co-registrants included in a consolidating entity’s EDGAR submission, separated by spaces. If there are no other co-registrants (i.e., nciks=1), the value of aciks is NULL. For a very small number of filers, the entire list of co-registrants is too long to fit in the field. Where this is the case, users should refer to the complete submission file for all CIK information.

Numbers

adsh	ddate	tag	value	uom	qtrs	version	segments	footnote
0001628280-25-020463	20231231	Accounts Payable Current And Noncurrent	22300000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20241231	Fixed Income Debt Securities Available For Sale	4692200000.0000	USD	0	0001628280-25-020463
0001628280-25-020463	20231231	Accumulated Other Comprehensive Income Loss Net Of Tax	-400300000.0000	USD	0	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20231231	Cash And Cash Equivalents At Carrying Value	1028100000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20231231	Cash And Cash Equivalents Includes Restricted Cash	323200000.0000	USD	0	0001628280-25-020463
0001628280-25-020463	20231231	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect	-900000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20241231	Catastrophe Bonds Fair Value Disclosure	1000000.0000	USD	0	0001628280-25-020463	Fair Value By Measurement Frequency= Fair Value Measurements Recurring; Investment Type= Trading Assets Excluding Debt And Equity Securities;
0001628280-25-020463	20241231	Common Stock Value	100000.0000	USD	0	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20221231	Comprehensive Income Net Of Tax	-332200000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20241231	Debt Securities Gain Loss	-102100000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20231231	Deferred Income Tax Liabilities Net	1600000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20231231	Derivative Assets	31700000.0000	USD	0	us-gaap/2024	Derivative Instrument Risk= Foreign Exchange Contract; Fair Value By Asset Class= Derivative Financial Instruments Assets; Fair Value By Measurement Frequency= Fair Value Measurements Recurring;
0001628280-25-020463	20240331	Dividends	6595600.0000	USD	1	us-gaap/2024	Class Of Stock= Series D Preferred Stock;
0001628280-25-020463	20240331	Dividends	3515600.0000	USD	1	us-gaap/2024	Class Of Stock= Series F Preferred Stock;
0001628280-25-020463	20241231	Dividends	54948800.0000	USD	4	us-gaap/2024
0001628280-25-020463	20221231	Earnings Per Share Diluted	0.0700	USD	4	us-gaap/2024
0001628280-25-020463	20221231	Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents	-18800000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20241231	Equity Method Investments	6500000.0000	USD	0	us-gaap/2024	Schedule Of Equity Method Investment Equity Method Investee Name= Multi Line Reinsurer;
0001628280-25-020463	20241231	Fixed Income Debt Securities Trading	74900000.0000	USD	0	0001628280-25-020463	Fair Value By Measurement Frequency= Fair Value Measurements Recurring; Related Party Transactions By Related Party= C L Os;
0001628280-25-020463	20241231	Fixed Income Debt Securities Trading Amortized Cost	1207700000.0000	USD	0	0001628280-25-020463
0001628280-25-020463	20231231	Gain Loss On Investments	17800000.0000	USD	4	us-gaap/2024	Investment Type= Other Aggregated Investments;
0001628280-25-020463	20231231	Gain Loss On Investments	-400000.0000	USD	4	us-gaap/2024	Related Party Transaction= Apollo Real Estate Fund;
0001628280-25-020463	20221231	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments	-27000000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20231231	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments	402600000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20231231	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments	40200000.0000	USD	4	us-gaap/2024	Equity Components= Accumulated Net Investment Gain Loss Including Portion Attributable To Noncontrolling Interest; Reclassification Out Of Accumulated Other Comprehensive Income= Reclassification Out Of Accumulated Other Comprehensive Income;
0001628280-25-020463	20241231	Income Tax Receivable	900000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20231231	Increase Decrease In Deferred Income Taxes	197700000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20221231	Increase Decrease In Liability For Claims And Claims Adjustment Expense Reserve	99100000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20221231	Increase Decrease In Premiums Receivable	177800000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20241231	Increase Decrease In Prepaid Reinsurance Premiums	168200000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20221231	Increase Decrease In Unearned Premiums	345200000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20241231	Insurance Reserves	10768400000.0000	USD	0	0001628280-25-020463
0001628280-25-020463	20221231	Net Cash Provided By Used In Investing Activities	2800000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20241231	Net Income Loss	486100000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20221231	Operating Lease Payments	600000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20241231	Operating Lease Right Of Use Asset	53500000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20231231	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax	14400000.0000	USD	4	us-gaap/2024	Equity Components= Accumulated Translation Adjustment;
0001628280-25-020463	20231231	Other Comprehensive Income Loss Net Of Tax	106000000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20241231	Other Comprehensive Income Loss Net Of Tax	10200000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20221231	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax	-447200000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20231231	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax	86000000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20221231	Other Income	1000000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20221231	Paymentsfor Proceedsfrom Investing Activities Netof Cash	-5900000.0000	USD	4	0001628280-25-020463
0001628280-25-020463	20231231	Payments For Proceeds From Other Investing Activities	9300000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20221231	Payments For Repurchase Of Preferred Stock And Preference Stock	0.0000	USD	4	us-gaap/2024
0001628280-25-020463	20241231	Payments For Repurchase Of Preferred Stock And Preference Stock	275000000.0000	USD	4	us-gaap/2024	Equity Components= Parent;
0001628280-25-020463	20221231	Payments Of Dividends Common Stock	40000000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20241231	Payments Of Dividends Common Stock	195000000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20241231	Payments To Acquire Privately Held Investments Trading	57000000.0000	USD	4	0001628280-25-020463
0001628280-25-020463	20250228	Preferred Stock Dividend Rate Percentage	0.0700	pure	0	us-gaap/2024	Class Of Stock= Series G Preferred Stock; Subsequent Event Type= Subsequent Event;
0001628280-25-020463	20130430	Preferred Stock Issuance Cost	4400000.0000	USD	0	0001628280-25-020463	Class Of Stock= Series D Preferred Stock;
0001628280-25-020463	20160930	Preferred Stock Issuance Cost	8700000.0000	USD	0	0001628280-25-020463	Class Of Stock= Series E Preferred Stock;
0001628280-25-020463	20130430	Preferred Stock Shares Issued	11000000000000.0000	shares	0	us-gaap/2024	Class Of Stock= Series D Preferred Stock;
0001628280-25-020463	20241231	Preferred Stock Shares Issued	10000000.0000	shares	0	us-gaap/2024	Class Of Stock= Series E Preferred Stock;
0001628280-25-020463	20231231	Preferred Stock Value	753500000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20241231	Preferred Stock Value	970500000.0000	USD	0	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20221231	Premiums Earned Net	1436900000.0000	USD	4	us-gaap/2024	Business Segments= Insurance;
0001628280-25-020463	20241231	Premiums Earned Net	1584000000.0000	USD	4	us-gaap/2024	Business Segments= Insurance; Consolidation Items= Operating Segments;
0001628280-25-020463	20241231	Premiums Earned Net	1305700000.0000	USD	4	us-gaap/2024	Business Segments= Reinsurance;
0001628280-25-020463	20231231	Premiums Receivable Allowance For Doubtful Accounts	21000000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20241231	Privately Held Investments Available For Sale At Fair Value	0.0000	USD	0	0001628280-25-020463	Fair Value By Measurement Frequency= Fair Value Measurements Recurring; Related Party Transactions By Related Party= Apollo Originating Partnership;
0001628280-25-020463	20231231	Proceeds From Issuance Of Preferred Stock And Preference Stock	0.0000	USD	4	us-gaap/2024
0001628280-25-020463	20241231	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities	850100000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20221231	Proceeds From Sale Of Short Term Investments	2600000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20221231	Proceeds From Term Loan Facility	0.0000	USD	4	0001628280-25-020463
0001628280-25-020463	20241231	Proceeds From Term Loan Facility	0.0000	USD	4	0001628280-25-020463	Equity Components= Parent;
0001628280-25-020463	20231231	Purchases Of Privately Held Investments Available For Sale	14700000.0000	USD	4	0001628280-25-020463
0001628280-25-020463	20231231	Purchases Of Proceeds From Catastrophe Bonds	-1500000.0000	USD	4	0001628280-25-020463
0001628280-25-020463	20221231	Reinsurance Recoverables Allowance	3700000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20241231	Reinsurance Recoverables On Paid And Unpaid Losses	4172000000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20241231	Repayments Of Short Term Debt	0.0000	USD	4	us-gaap/2024
0001628280-25-020463	20231231	Revenues	2966100000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20241231	Revenues	3260300000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20241231	Revenues	625100000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20231231	Short Term Investments Available For Sale	93600000.0000	USD	0	0001628280-25-020463
0001628280-25-020463	20231231	Stockholders Equity Including Portion Attributable To Noncontrolling Interest	-200000.0000	USD	0	us-gaap/2024	Equity Components= Accumulated Gain Loss Cash Flow Hedge Including Noncontrolling Interest;
0001628280-25-020463	20231231	Stockholders Equity Including Portion Attributable To Noncontrolling Interest	761700000.0000	USD	0	us-gaap/2024	Equity Components= Additional Paid In Capital;
0001628280-25-020463	20231231	Stock Issued During Period Value New Issues	0.0000	USD	4	us-gaap/2024	Equity Components= Preferred Stock;
0001628280-25-020463	20231231	Unearned Premiums	2426300000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20231231	Unrealized Gainloss On Real Estate Fund In Net Investment Income	-17900000.0000	USD	4	0001628280-25-020463
0001628280-25-020465	20231231	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations	1028100000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20241231	Common Stock Value	100000.0000	USD	0	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020465	20221231	Debt Securities Gain Loss	-182600000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Debt Securities Gain Loss	8700000.0000	USD	4	us-gaap/2024	Related Party Transaction= Class A B Notes;
0001628280-25-020465	20241231	Debt Securities Gain Loss	-102100000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Deferred Income Tax Liabilities Net	1600000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20241231	Deferred Policy Acquisition Cost Amortization Expense	193200000.0000	USD	4	us-gaap/2024	Business Segments= Insurance; Consolidation Items= Operating Segments;
0001628280-25-020465	20241231	Dividends	13847200.0000	USD	1	us-gaap/2024
0001628280-25-020465	20241231	Dividends	3516000.0000	USD	1	us-gaap/2024	Class Of Stock= Series E Preferred Stock;
0001628280-25-020465	20221231	Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents	-18800000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Gain Loss On Investments	17800000.0000	USD	4	us-gaap/2024	Investment Type= Other Aggregated Investments;
0001628280-25-020465	20221231	Gains Losses On Investment And Foreign Exchange	-15900000.0000	USD	4	0001628280-25-020465
0001628280-25-020465	20231231	General And Administrative Expense	5000000.0000	USD	4	us-gaap/2024	Related Party Transaction= Management Consulting Agreement;
0001628280-25-020465	20221231	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments	-27000000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments	40200000.0000	USD	4	us-gaap/2024	Equity Components= Accumulated Net Investment Gain Loss Including Portion Attributable To Noncontrolling Interest; Reclassification Out Of Accumulated Other Comprehensive Income= Reclassification Out Of Accumulated Other Comprehensive Income;
0001628280-25-020465	20241231	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments	464100000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Income Tax Expense Benefit	0.0000	USD	4	us-gaap/2024	Equity Components= Accumulated Gain Loss Cash Flow Hedge Including Noncontrolling Interest; Reclassification Out Of Accumulated Other Comprehensive Income= Reclassification Out Of Accumulated Other Comprehensive Income;
0001628280-25-020465	20221231	Increase Decrease In Liability For Claims And Claims Adjustment Expense Reserve	99100000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20221231	Increase Decrease In Premiums Receivable	177800000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20241231	Increase Decrease In Prepaid Reinsurance Premiums	168200000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20241231	Increase Decrease In Reinsurance Payables	-515500000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20221231	Increase Decrease In Unearned Premiums	345200000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Interest Paid	15600000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Investments Excluding Derivative Assets	6412400000.0000	USD	0	0001628280-25-020465
0001628280-25-020465	20241231	Liabilities	12376600000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20241231	Liabilities And Stockholders Equity	3790400000.0000	USD	0	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020465	20221231	Liability For Claims And Claims Adjustment Expense	1360700000.0000	USD	0	us-gaap/2024	Business Segments= Reinsurance;
0001628280-25-020465	20231231	Net Changein Receivablefor Securities Soldor Payablefor Securities Purchased	19900000.0000	USD	4	0001628280-25-020465
0001628280-25-020465	20241231	Net Income Loss	486100000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20221231	Net Income Loss From Continuing Operations Available To Common Shareholders Basic	6500000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20221231	Operating Lease Payments	600000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020465	20231231	Other Assets	5600000.0000	USD	0	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020465	20221231	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax	-367800000.0000	USD	4	us-gaap/2024	Equity Components= Accumulated Net Unrealized Investment Gain Loss;
0001628280-25-020465	20221231	Other Comprehensive Income Loss Before Tax	-407200000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Before Tax	14400000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Other Comprehensive Income Loss Net Of Tax	106000000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020465	20241231	Other Comprehensive Income Loss Net Of Tax	10200000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Other Comprehensive Income Loss Tax Portion Attributable To Parent1	20600000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20221231	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax	-447200000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax	86000000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Other Expenses	0.0000	USD	4	us-gaap/2024
0001628280-25-020465	20221231	Paymentsfor Proceedsfrom Investing Activities Netof Cash	-5900000.0000	USD	4	0001628280-25-020465
0001628280-25-020465	20231231	Payments For Proceeds From Other Investing Activities	9300000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20241231	Payments For Repurchase Of Preferred Stock And Preference Stock	275000000.0000	USD	4	us-gaap/2024	Equity Components= Parent;
0001628280-25-020465	20241231	Payments To Acquire Equity Method Investments	0.0000	USD	4	us-gaap/2024	Schedule Of Equity Method Investment Equity Method Investee Name= Multi Line Reinsurer;
0001628280-25-020465	20241231	Payments To Acquire Trading Securities Heldforinvestment	544600000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20160930	Preferred Stock Dividend Rate Percentage	0.0563	pure	0	us-gaap/2024	Class Of Stock= Series E Preferred Stock;
0001628280-25-020465	20241130	Preferred Stock Dividend Rate Percentage	0.0595	pure	0	us-gaap/2024	Class Of Stock= Series D Preferred Stock;
0001628280-25-020465	20241231	Preferred Stock Dividend Rate Percentage	0.0563	pure	4	us-gaap/2024	Class Of Stock= Series F Preferred Stock;
0001628280-25-020465	20250228	Preferred Stock Dividend Rate Percentage	0.0700	pure	0	us-gaap/2024	Class Of Stock= Series G Preferred Stock; Subsequent Event Type= Subsequent Event;
0001628280-25-020465	20241130	Preferred Stock Issuance Cost	8000000.0000	USD	0	0001628280-25-020465	Class Of Stock= Series G Preferred Stock;
0001628280-25-020465	20130430	Preferred Stock Shares Issued	11000000000000.0000	shares	0	us-gaap/2024	Class Of Stock= Series D Preferred Stock;
0001628280-25-020465	20231231	Preferred Stock Value	753500000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20241231	Preferred Stock Value	970500000.0000	USD	0	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020465	20221231	Premiums Earned Net	2688700000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20241231	Premiums Earned Net	1584000000.0000	USD	4	us-gaap/2024	Business Segments= Insurance; Consolidation Items= Operating Segments;
0001628280-25-020465	20241231	Premiums Earned Net	1305700000.0000	USD	4	us-gaap/2024	Business Segments= Reinsurance; Consolidation Items= Operating Segments;
0001628280-25-020465	20231231	Premiums Receivable Allowance For Doubtful Accounts	21000000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20241231	Premiums Receivable At Carrying Value	1617000000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20241231	Privately Held Investments Amortized Cost Available For Sale	24000000.0000	USD	0	0001628280-25-020465
0001628280-25-020465	20241231	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities	850100000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20241231	Proceeds From Term Loan Facility	0.0000	USD	4	0001628280-25-020465	Equity Components= Parent;
0001628280-25-020465	20241231	Repayments Of Short Term Debt	0.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Revenues	2966100000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Revenues	673400000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20231231	Other Assets	5600000.0000	USD	0	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20231231	Accrued Liabilities Current And Noncurrent	7600000.0000	USD	0	us-gaap/2024	Award Type= Stock Compensation Plan;
0001628280-25-020463	20241231	Aggregate Liquidation Preference Shares	1000000000.0000	USD	4	0001628280-25-020463
0001628280-25-020463	20221231	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect	-354900000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20231231	Catastrophe Bonds Fair Value Disclosure	0.0000	USD	0	0001628280-25-020463	Fair Value By Fair Value Hierarchy Level= Fair Value Inputs Level3; Fair Value By Measurement Frequency= Fair Value Measurements Recurring; Investment Type= Trading Assets Excluding Debt And Equity Securities;
0001628280-25-020463	20231231	Comprehensive Income Net Of Tax	640700000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20221231	Deferred Policy Acquisition Cost Amortization Expense	179400000.0000	USD	4	us-gaap/2024	Business Segments= Insurance; Consolidation Items= Operating Segments;
0001628280-25-020463	20231231	Deferred Policy Acquisition Cost Amortization Expense	208600000.0000	USD	4	us-gaap/2024	Business Segments= Reinsurance; Consolidation Items= Operating Segments;
0001628280-25-020463	20241231	Deferred Policy Acquisition Cost Amortization Expense	193200000.0000	USD	4	us-gaap/2024	Business Segments= Insurance; Consolidation Items= Operating Segments;
0001628280-25-020463	20241231	Depreciation Amortization And Accretion Net	-1000000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20221231	Derivative Gain Loss On Derivative Net	-80500000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20240630	Dividends	13700900.0000	USD	1	us-gaap/2024
0001628280-25-020463	20240930	Dividends	13773500.0000	USD	1	us-gaap/2024
0001628280-25-020463	20241231	Dividends	6815600.0000	USD	1	us-gaap/2024	Class Of Stock= Series D Preferred Stock;
0001628280-25-020463	20241231	Dividends	14062400.0000	USD	4	us-gaap/2024	Class Of Stock= Series F Preferred Stock;
0001628280-25-020463	20221231	Earnings Per Share Basic	0.0700	USD	4	us-gaap/2024
0001628280-25-020463	20231231	Earnings Per Share Basic	5.3400	USD	4	us-gaap/2024
0001628280-25-020463	20241231	Earnings Per Share Diluted	4.7500	USD	4	us-gaap/2024
0001628280-25-020463	20231231	Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents	6600000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20231231	Equity Method Investments	6400000.0000	USD	0	us-gaap/2024	Schedule Of Equity Method Investment Equity Method Investee Name= Multi Line Reinsurer;
0001628280-25-020463	20241231	Finance Lease Right Of Use Asset Amortization	700000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20231231	General And Administrative Expense	354500000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20241231	General And Administrative Expense	141700000.0000	USD	4	us-gaap/2024	Business Segments= Reinsurance; Consolidation Items= Operating Segments;
0001628280-25-020463	20221231	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments	51100000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20231231	Operating Lease Payments	15500000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20241231	Operating Lease Payments	15900000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20241231	Other Comprehensive Income Loss Before Tax	13500000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20241231	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax Parent	-5100000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20241231	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments	59400000.0000	USD	4	us-gaap/2024	Equity Components= Accumulated Net Investment Gain Loss Including Portion Attributable To Noncontrolling Interest; Reclassification Out Of Accumulated Other Comprehensive Income= Reclassification Out Of Accumulated Other Comprehensive Income;
0001628280-25-020463	20241231	Income Taxes Paid Net	69000000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20221231	Increase Decrease In Accrued Income Taxes Payable	-1300000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20231231	Increase Decrease In Accrued Income Taxes Payable	3500000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20221231	Increase Decrease In Accrued Liabilities	-87000000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20231231	Increase Decrease In Prepaid Reinsurance Premiums	-3800000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20231231	Increase Decrease In Reinsurance Payables	-563500000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20231231	Increase Decrease In Unearned Premiums	-31200000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20241231	Increase Decrease In Unpaid Losses Recoverable From Reinsurers	405800000.0000	USD	4	0001628280-25-020463
0001628280-25-020463	20221231	Interest On Operating Lease Liabilities	5400000.0000	USD	4	0001628280-25-020463
0001628280-25-020463	20241231	Interest Paid	20500000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20231231	Liability For Claims And Claims Adjustment Expense	27300000.0000	USD	0	us-gaap/2024	Product Or Service= Other Longduration Insurance Product Line;
0001628280-25-020463	20231231	Net Cash Provided By Used In Investing Activities	-172200000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20241231	Net Cash Provided By Used In Investing Activities	-352800000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20221231	Net Cash Provided By Used In Operating Activities	-55000000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20221231	Net Investment Income	188100000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20241231	Operating Lease Impairment Loss	0.0000	USD	4	us-gaap/2024
0001628280-25-020463	20241231	Operating Lease Liability	900000.0000	USD	0	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20221231	Operating Lease Payments	15500000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20221231	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Before Tax	-30900000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20231231	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Before Tax	14400000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20231231	Other Comprehensive Income Loss Net Of Tax	106000000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20241231	Other Expenses	0.0000	USD	4	us-gaap/2024
0001628280-25-020463	20241231	Other Income	0.0000	USD	4	us-gaap/2024
0001628280-25-020463	20231231	Payments For Proceeds From Productive Assets	8900000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20221231	Payments For Repurchase Of Preferred Stock And Preference Stock	0.0000	USD	4	us-gaap/2024	Equity Components= Parent;
0001628280-25-020463	20231231	Payments For Repurchase Of Preferred Stock And Preference Stock	0.0000	USD	4	us-gaap/2024		On January 1, 2025, the Company redeemed all 11,000,000 shares of its issued and outstanding 5.950% Fixed-to-Floating Rate Perpetual Non-Cumulative Preference Shares. The redemption price was paid on January 2, 2025. To facilitate this redemption, the funds of $275.0 million were transferred to a third party transfer agent on December 30, 2024 and are included in other assets in the consolidated balance sheet. The cash flow has been included under financing activities above. For further details, refer to No
0001628280-25-020463	20231231	Payments For Repurchase Of Preferred Stock And Preference Stock	0.0000	USD	4	us-gaap/2024	Equity Components= Parent;
0001628280-25-020463	20231231	Payments Of Dividends Preferred Stock And Preference Stock	49900000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20210331	Payments To Acquire Equity Method Investments	800000.0000	USD	0	us-gaap/2024	Schedule Of Equity Method Investment Equity Method Investee Name= M V I;
0001628280-25-020463	20231231	Payments To Acquire Equity Method Investments	400000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20241231	Payments To Acquire Trading Securities Heldforinvestment	544600000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20190731	Preferred Stock Dividend Rate Percentage	0.0563	pure	0	us-gaap/2024	Class Of Stock= Series F Preferred Stock;
0001628280-25-020463	20130430	Preferred Stock Liquidation Preference Value	275000000.0000	USD	0	us-gaap/2024	Class Of Stock= Series D Preferred Stock;
0001628280-25-020463	20241231	Premiums Receivable Allowance For Doubtful Accounts	24600000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20241231	Privately Held Investments Amortized Cost Available For Sale	24000000.0000	USD	0	0001628280-25-020463
0001628280-25-020463	20231231	Privately Held Investments Available For Sale At Fair Value	0.0000	USD	0	0001628280-25-020463	Fair Value By Fair Value Hierarchy Level= Fair Value Inputs Level1; Fair Value By Measurement Frequency= Fair Value Measurements Recurring; Financial Instrument= Trading Assets Excluding Debt And Equity Securities;
0001628280-25-020463	20231231	Profit Loss	534700000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20221231	Selling General And Administrative Expense	494200000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Selling General And Administrative Expense	503600000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20241231	Short Term Borrowings	300000000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20231231	Short Term Investments Available For Sale	93600000.0000	USD	0	0001628280-25-020465
0001628280-25-020465	20241231	Short Term Investments Available For Sale	261900000.0000	USD	0	0001628280-25-020465
0001628280-25-020465	20231231	Stockholders Equity Including Portion Attributable To Noncontrolling Interest	-200000.0000	USD	0	us-gaap/2024	Equity Components= Accumulated Gain Loss Cash Flow Hedge Including Noncontrolling Interest;
0001628280-25-020465	20231231	Stockholders Equity Including Portion Attributable To Noncontrolling Interest	100000.0000	USD	0	us-gaap/2024	Equity Components= Common Stock;
0001628280-25-020465	20221231	Stock Issued During Period Value New Issues	0.0000	USD	4	us-gaap/2024	Equity Components= Preferred Stock;
0001628280-25-020465	20241231	Stock Issued During Period Value New Issues	217000000.0000	USD	4	us-gaap/2024	Equity Components= Preferred Stock;
0001628280-25-020465	20231231	Unearned Premiums	2426300000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20231231	Privately Held Investments Available For Sale At Fair Value	14900000.0000	USD	0	0001628280-25-020463	Fair Value By Measurement Frequency= Fair Value Measurements Recurring; Financial Instrument= Trading Assets Excluding Debt And Equity Securities;
0001628280-25-020463	20241231	Privately Held Investments Available For Sale At Fair Value	0.0000	USD	0	0001628280-25-020463	Fair Value By Fair Value Hierarchy Level= Fair Value Inputs Level1; Fair Value By Measurement Frequency= Fair Value Measurements Recurring; Investment Type= Privately Held Investments Available For Sale;
0001628280-25-020463	20241231	Proceeds From Issuance Of Preferred Stock And Preference Stock	217000000.0000	USD	4	us-gaap/2024	Equity Components= Parent;
0001628280-25-020463	20221231	Proceeds From Sale Of Available For Sale Securities Debt	2212500000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20241231	Proceeds From Sale Of Short Term Investments	6700000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20221231	Proceeds From Term Loan Facility	0.0000	USD	4	0001628280-25-020463	Equity Components= Parent;
0001628280-25-020463	20231231	Proceeds From Term Loan Facility	300000000.0000	USD	4	0001628280-25-020463	Equity Components= Parent;
0001628280-25-020463	20221231	Profit Loss	55000000.0000	USD	4	us-gaap/2024	Equity Components= Accumulated Net Investment Gain Loss Including Portion Attributable To Noncontrolling Interest; Reclassification Out Of Accumulated Other Comprehensive Income= Reclassification Out Of Accumulated Other Comprehensive Income;
0001628280-25-020463	20241231	Reinsurance Payable	901100000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20241231	Reinsurance Recoverables Allowance	27500000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20231231	Retained Earnings Accumulated Deficit	1793500000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20241231	Retained Earnings Accumulated Deficit	2029700000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20241231	Short Term Borrowings	0.0000	USD	0	us-gaap/2024	Short Term Debt Type= Short Term Debt;
0001628280-25-020463	20241231	Shortterminvestmentsavailableforsaleamortizedcost	261900000.0000	USD	0	0001628280-25-020463
0001628280-25-020463	20221231	Stockholders Equity Including Portion Attributable To Noncontrolling Interest	753500000.0000	USD	0	us-gaap/2024	Equity Components= Preferred Stock;	Preference shares of $1,000.0 million, less issuance costs of $29.5 million (December 31, 2023 and 2022 $775.0 million and $21.5 million).
0001628280-25-020463	20241231	Stockholders Equity Including Portion Attributable To Noncontrolling Interest	3371900000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20241231	Stockholders Equity Including Portion Attributable To Noncontrolling Interest	-5300000.0000	USD	0	us-gaap/2024	Equity Components= Accumulated Gain Loss Cash Flow Hedge Including Noncontrolling Interest;
0001628280-25-020463	20241231	Stockholders Equity Including Portion Attributable To Noncontrolling Interest	-198200000.0000	USD	0	us-gaap/2024	Equity Components= Accumulated Net Unrealized Investment Gain Loss;
0001628280-25-020465	20231231	Accrued Liabilities Current And Noncurrent	7600000.0000	USD	0	us-gaap/2024	Award Type= Stock Compensation Plan;
0001628280-25-020465	20241231	Accrued Liabilities Current And Noncurrent	20700000.0000	USD	0	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020465	20211231	Cash And Cash Equivalents At Carrying Value	45000000.0000	USD	0	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020465	20241231	Cash And Cash Equivalents At Carrying Value	914200000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20231231	Catastrophe Bond	1600000.0000	USD	0	0001628280-25-020465
0001628280-25-020465	20241231	Catastrophe Bonds Fair Value Disclosure	1000000.0000	USD	0	0001628280-25-020465	Fair Value By Measurement Frequency= Fair Value Measurements Recurring; Investment Type= Trading Assets Excluding Debt And Equity Securities;
0001628280-25-020465	20221231	Depreciation Amortization And Accretion Net	43300000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20241231	Depreciation Amortization And Accretion Net	-1000000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20240331	Dividends	6595600.0000	USD	1	us-gaap/2024	Class Of Stock= Series D Preferred Stock;
0001628280-25-020465	20240630	Dividends	13700900.0000	USD	1	us-gaap/2024
0001628280-25-020465	20241231	Dividends	6815600.0000	USD	1	us-gaap/2024	Class Of Stock= Series D Preferred Stock;
0001628280-25-020465	20241231	Dividends	14062400.0000	USD	4	us-gaap/2024	Class Of Stock= Series F Preferred Stock;
0001628280-25-020465	20231231	Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents	6600000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20241231	Finance Lease Right Of Use Asset Amortization	700000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020465	20231231	Fixed Income Debt Securities Available For Sale Allowance For Credit Loss	2900000.0000	USD	0	0001628280-25-020465
0001628280-25-020465	20241231	Fixed Income Debt Securities Available For Sale Including Related Party Investments	14000000.0000	USD	0	0001628280-25-020465	Fair Value By Measurement Frequency= Fair Value Measurements Recurring; Related Party Transactions By Related Party= C L Os;
0001628280-25-020465	20241231	Fixed Income Debt Securities Trading	74900000.0000	USD	0	0001628280-25-020465	Fair Value By Measurement Frequency= Fair Value Measurements Recurring; Related Party Transactions By Related Party= C L Os;
0001628280-25-020465	20221231	General And Administrative Expense	386500000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	General And Administrative Expense	354500000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20241231	General And Administrative Expense	141700000.0000	USD	4	us-gaap/2024	Business Segments= Reinsurance; Consolidation Items= Operating Segments;
0001628280-25-020465	20221231	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments	51100000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020465	20231231	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments	402600000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20241231	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments	59400000.0000	USD	4	us-gaap/2024	Equity Components= Accumulated Net Investment Gain Loss Including Portion Attributable To Noncontrolling Interest; Reclassification Out Of Accumulated Other Comprehensive Income= Reclassification Out Of Accumulated Other Comprehensive Income;
0001628280-25-020465	20241231	Income Taxes Paid Net	69000000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20221231	Increase Decrease In Accrued Income Taxes Payable	-1300000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Increase Decrease In Accrued Income Taxes Payable	3500000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20221231	Increase Decrease In Deferred Income Taxes	104600000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Increase Decrease In Other Operating Assets	-62200000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Increase Decrease In Prepaid Reinsurance Premiums	-3800000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Increase Decrease In Unearned Premiums	-31200000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20241231	Increase Decrease In Unpaid Losses Recoverable From Reinsurers	405800000.0000	USD	4	0001628280-25-020465
0001628280-25-020465	20241231	Interest Paid	20500000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20221231	Liability For Claims And Claims Adjustment Expense	1452500000.0000	USD	0	us-gaap/2024	Business Segments= Insurance;
0001628280-25-020465	20231231	Liability For Claims And Claims Adjustment Expense	27300000.0000	USD	0	us-gaap/2024	Product Or Service= Other Longduration Insurance Product Line;
0001628280-25-020465	20231231	Net Cash Provided By Used In Investing Activities	-172200000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20221231	Net Investment Income	3100000.0000	USD	4	us-gaap/2024	Related Party Transactions By Related Party= Management Consulting Agreement;
0001628280-25-020465	20231231	Net Investment Income	275700000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20241231	Operating Lease Liability	900000.0000	USD	0	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020465	20231231	Operating Lease Payments	15500000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20221231	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax	-367800000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20241231	Other Comprehensive Income Loss Before Tax	13500000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20221231	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax Parent	15400000.0000	USD	4	us-gaap/2024	Equity Components= Accumulated Translation Adjustment;
0001628280-25-020465	20241231	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax Parent	-5100000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020465	20221231	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Before Tax	-30900000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Other Comprehensive Income Loss Net Of Tax	106000000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Other Income	3200000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020465	20241231	Other Income	0.0000	USD	4	us-gaap/2024
0001628280-25-020465	20221231	Payments For Proceeds From Other Investing Activities	62500000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Payments For Proceeds From Productive Assets	8900000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Payments For Repurchase Of Preferred Stock And Preference Stock	0.0000	USD	4	us-gaap/2024	Equity Components= Parent;
0001628280-25-020465	20221231	Payments Of Dividends Common Stock	40000000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20241231	Payments Of Dividends Common Stock	195000000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Payments Of Dividends Preferred Stock And Preference Stock	49900000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20210331	Payments To Acquire Equity Method Investments	800000.0000	USD	0	us-gaap/2024	Schedule Of Equity Method Investment Equity Method Investee Name= M V I;
0001628280-25-020465	20241231	Preferred Stock Dividend Rate Percentage	0.0595	pure	0	us-gaap/2024	Class Of Stock= Series D Preferred Stock; Subsequent Event Type= Subsequent Event;
0001628280-25-020465	20241231	Preferred Stock Dividend Rate Percentage	0.0563	pure	4	us-gaap/2024	Class Of Stock= Series E Preferred Stock;
0001628280-25-020465	20130430	Preferred Stock Liquidation Preference Value	275000000.0000	USD	0	us-gaap/2024	Class Of Stock= Series D Preferred Stock;
0001628280-25-020465	20231231	Preferred Stock Shares Issued	10000000.0000	shares	0	us-gaap/2024	Class Of Stock= Series E Preferred Stock;
0001628280-25-020465	20241231	Premiums Receivable Allowance For Doubtful Accounts	24600000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20231231	Privately Held Investments Available For Sale At Fair Value	14900000.0000	USD	0	0001628280-25-020465	Fair Value By Fair Value Hierarchy Level= Fair Value Inputs Level3; Fair Value By Measurement Frequency= Fair Value Measurements Recurring; Financial Instrument= Trading Assets Excluding Debt And Equity Securities;
0001628280-25-020465	20231231	Privately Held Investments Available For Sale At Fair Value	14900000.0000	USD	0	0001628280-25-020465	Fair Value By Measurement Frequency= Fair Value Measurements Recurring; Financial Instrument= Trading Assets Excluding Debt And Equity Securities;
0001628280-25-020465	20241231	Privately Held Investments Available For Sale At Fair Value	0.0000	USD	0	0001628280-25-020465	Fair Value By Measurement Frequency= Fair Value Measurements Recurring; Related Party Transactions By Related Party= Apollo Originating Partnership;
0001628280-25-020465	20241231	Proceeds From Issuance Of Preferred Stock And Preference Stock	217000000.0000	USD	4	us-gaap/2024	Equity Components= Parent;
0001628280-25-020465	20231231	Profit Loss	534700000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20221231	Redeemable Preferred Stock Dividends	44600000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20241231	Reinsurance Payable	901100000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20221231	Reinsurance Recoverables Allowance	3700000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20241231	Reinsurance Recoverables Allowance	27500000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20221231	Repayments Of Short Term Debt	0.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Retained Earnings Accumulated Deficit	1793500000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20241231	Retained Earnings Accumulated Deficit	2029700000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20241231	Short Term Borrowings	0.0000	USD	0	us-gaap/2024	Short Term Debt Type= Short Term Debt;
0001628280-25-020465	20221231	Stockholders Equity Including Portion Attributable To Noncontrolling Interest	-333200000.0000	USD	0	us-gaap/2024	Equity Components= Accumulated Net Unrealized Investment Gain Loss;
0001628280-25-020465	20241231	Stockholders Equity Including Portion Attributable To Noncontrolling Interest	-198200000.0000	USD	0	us-gaap/2024	Equity Components= Accumulated Net Unrealized Investment Gain Loss;
0001628280-25-020465	20231231	Unrealized Gainloss On Real Estate Fund In Net Investment Income	-17900000.0000	USD	4	0001628280-25-020465
0001628280-25-020463	20231231	Accumulated Other Comprehensive Income Loss Net Of Tax	-400300000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20231231	Aggregate Liquidation Preference Shares	775000000.0000	USD	4	0001628280-25-020463
0001628280-25-020463	20231231	Assets	3382300000.0000	USD	0	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20241231	Assets	15748500000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20241231	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect	-113900000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20241231	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect	0.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20241231	Catastrophe Bond	1000000.0000	USD	0	0001628280-25-020463
0001628280-25-020463	20241231	Catastrophe Bonds Fair Value Disclosure	1000000.0000	USD	0	0001628280-25-020463
0001628280-25-020463	20231231	Commitments And Contingencies	0.0000	USD	0	us-gaap/2024
0001628280-25-020463	20241231	Commitments And Contingencies	0.0000	USD	0	us-gaap/2024
0001628280-25-020463	20221231	Comprehensive Income Net Of Tax	-332200000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20221231	Debt Securities Gain Loss	-400000.0000	USD	4	us-gaap/2024	Related Party Transaction= Class A B Notes;
0001628280-25-020463	20231231	Debt Securities Gain Loss	8700000.0000	USD	4	us-gaap/2024	Related Party Transaction= Class A B Notes;
0001628280-25-020463	20241231	Deferred Income Tax Liabilities Net	1100000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20241231	Deferred Policy Acquisition Cost Amortization Expense	420200000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20231231	Depreciation Amortization And Accretion Net	11000000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20231231	Derivative Liabilities	25800000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20240630	Dividends	6669300.0000	USD	1	us-gaap/2024	Class Of Stock= Series D Preferred Stock;
0001628280-25-020463	20240630	Dividends	3516000.0000	USD	1	us-gaap/2024	Class Of Stock= Series E Preferred Stock;
0001628280-25-020463	20221231	Equity Method Investments	200000.0000	USD	0	us-gaap/2024	Schedule Of Equity Method Investment Equity Method Investee Name= Digital Risk;
0001628280-25-020463	20231231	Equity Method Investments	200000.0000	USD	0	us-gaap/2024	Schedule Of Equity Method Investment Equity Method Investee Name= Digital Risk;
0001628280-25-020463	20231231	Fixed Income Debt Securities Available For Sale Allowance For Credit Loss	2900000.0000	USD	0	0001628280-25-020463
0001628280-25-020463	20231231	Fixed Income Debt Securities Available For Sale Amortized Cost	4330000000.0000	USD	0	0001628280-25-020463
0001628280-25-020463	20241231	Gain Loss On Sale Of Derivatives	6500000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20231231	General And Administrative Expense	233900000.0000	USD	4	us-gaap/2024	Business Segments= Insurance; Consolidation Items= Operating Segments;
0001628280-25-020463	20231231	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments	534700000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20241231	Income Tax Expense Benefit	4500000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20231231	Increase Decrease In Deferred Policy Acquisition Costs	-22800000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20221231	Increase Decrease In Other Operating Assets	24400000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20221231	Increase Decrease In Prepaid Reinsurance Premiums	141200000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20241231	Intangible Assets Net Including Goodwill	19900000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20221231	Interest Expense Debt	43700000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20241231	Interest Expense Debt	62100000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20231231	Net Cash Provided By Used In Investing Activities	-107400000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20231231	Net Income Loss From Continuing Operations Available To Common Shareholders Basic	484800000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20221231	Net Investment Income	0.0000	USD	4	us-gaap/2024	Related Party Transactions By Related Party= C L Os;
0001628280-25-020463	20241231	Net Investment Income	9200000.0000	USD	4	us-gaap/2024	Related Party Transaction= Asset Management Arrangement;
0001628280-25-020463	20221231	Operating Lease Impairment Loss	-6700000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20241231	Operating Lease Right Of Use Asset	1000000.0000	USD	0	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20221231	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax Parent	15400000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20231231	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Before Tax	-14000000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20241231	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Before Tax	-6500000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20221231	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Tax	0.0000	USD	4	us-gaap/2024
0001628280-25-020463	20221231	Other Comprehensive Income Loss Net Of Tax	-383300000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20241231	Other Comprehensive Income Loss Net Of Tax	10200000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20241231	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax	-25300000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20241231	Other Investments	78600000.0000	USD	0	us-gaap/2024	Fair Value By Measurement Frequency= Fair Value Measurements Recurring; Related Party Transaction= Apollo Real Estate Fund;
0001628280-25-020463	20241231	Other Investments	78600000.0000	USD	0	us-gaap/2024	Fair Value By Measurement Frequency= Fair Value Measurements Recurring; Related Party Transactions By Related Party= Funds Managed By Apollo;
0001628280-25-020463	20241231	Paymentsfor Availableforsale Securities Shortterm	334700000.0000	USD	4	0001628280-25-020463
0001628280-25-020463	20241231	Paymentsfor Proceedsfrom Investing Activities Netof Cash	-8500000.0000	USD	4	0001628280-25-020463
0001628280-25-020463	20241231	Payments For Proceeds From Productive Assets	17500000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20221231	Payments Of Dividends Preferred Stock And Preference Stock	44600000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20161231	Payments To Acquire Equity Method Investments	2300000.0000	USD	0	us-gaap/2024	Schedule Of Equity Method Investment Equity Method Investee Name= Digital Risk;
0001628280-25-020463	20221231	Policyholder Benefits And Claims Incurred Net	1680000000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20221231	Policyholder Benefits And Claims Incurred Net	770300000.0000	USD	4	us-gaap/2024	Business Segments= Reinsurance; Consolidation Items= Operating Segments;
0001628280-25-020463	20231231	Policyholder Benefits And Claims Incurred Net	1553000000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20231231	Policyholder Benefits And Claims Incurred Net	941900000.0000	USD	4	us-gaap/2024	Business Segments= Insurance; Consolidation Items= Operating Segments;
0001628280-25-020463	20231231	Preferred Stock Shares Issued	10000000.0000	shares	0	us-gaap/2024	Class Of Stock= Series F Preferred Stock;
0001628280-25-020463	20241231	Preferred Stock Shares Issued	10000000.0000	shares	0	us-gaap/2024	Class Of Stock= Series F Preferred Stock;
0001628280-25-020463	20231231	Preferred Stock Value	753500000.0000	USD	0	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20241231	Preferred Stock Value	970500000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20231231	Premiums Earned Net	1154500000.0000	USD	4	us-gaap/2024	Business Segments= Reinsurance; Consolidation Items= Operating Segments;
0001628280-25-020463	20241231	Prepaid Reinsurance Premiums	901700000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20231231	Privatelyheld Investments	475000000.0000	USD	0	0001628280-25-020463		Privately-held investments, trading at fair value include related party investments totaling $73.6 million (2023 $112.4 million). Privately-held investments, available for sale include related party investments totaling $Nil (2023 $14.9 million).
0001628280-25-020463	20241231	Privatelyheld Investments	73600000.0000	USD	0	0001628280-25-020463	Fair Value By Measurement Frequency= Fair Value Measurements Recurring; Related Party Transactions By Related Party= Apollo Originating Partnership;
0001628280-25-020463	20241231	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities	10300000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20221231	Purchases Of Proceeds From Catastrophe Bonds	-500000.0000	USD	4	0001628280-25-020463
0001628280-25-020463	20231231	Repayments Of Short Term Debt	300000000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20241231	Repayments Of Short Term Debt	0.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20221231	Selling General And Administrative Expense	494200000.0000	USD	4	us-gaap/2024		General, administrative and corporate expenses includes related party management consulting fees of $5.0 million (2023 $5.0 million; 2022 $5.0 million).
0001628280-25-020463	20231231	Selling General And Administrative Expense	121300000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20241231	Selling General And Administrative Expense	-900000.0000	USD	4	us-gaap/2024	Equity Components= Accumulated Gain Loss Cash Flow Hedge Including Noncontrolling Interest; Reclassification Out Of Accumulated Other Comprehensive Income= Reclassification Out Of Accumulated Other Comprehensive Income;
0001628280-25-020463	20241231	Short Term Investments Trading At Fair Value	1000000.0000	USD	0	0001628280-25-020463
0001628280-25-020463	20211231	Stockholders Equity Including Portion Attributable To Noncontrolling Interest	34600000.0000	USD	0	us-gaap/2024	Equity Components= Accumulated Net Unrealized Investment Gain Loss;
0001628280-25-020463	20211231	Stockholders Equity Including Portion Attributable To Noncontrolling Interest	753500000.0000	USD	0	us-gaap/2024	Equity Components= Preferred Stock;
0001628280-25-020463	20221231	Stockholders Equity Including Portion Attributable To Noncontrolling Interest	13800000.0000	USD	0	us-gaap/2024	Equity Components= Accumulated Gain Loss Cash Flow Hedge Including Noncontrolling Interest;
0001628280-25-020463	20221231	Stockholders Equity Including Portion Attributable To Noncontrolling Interest	761700000.0000	USD	0	us-gaap/2024	Equity Components= Additional Paid In Capital;
0001628280-25-020463	20241231	Stockholders Equity Including Portion Attributable To Noncontrolling Interest	970500000.0000	USD	0	us-gaap/2024	Equity Components= Preferred Stock;
0001628280-25-020463	20221231	Stock Issued During Period Value New Issues	0.0000	USD	4	us-gaap/2024	Equity Components= Preferred Stock;
0001628280-25-020465	20231231	Aggregate Liquidation Preference Shares	775000000.0000	USD	4	0001628280-25-020465
0001628280-25-020465	20231231	Assets	3382300000.0000	USD	0	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020465	20241231	Assets	15748500000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20241231	Catastrophe Bond	1000000.0000	USD	0	0001628280-25-020465
0001628280-25-020465	20231231	Catastrophe Bonds Fair Value Disclosure	0.0000	USD	0	0001628280-25-020465	Fair Value By Fair Value Hierarchy Level= Fair Value Inputs Level3; Fair Value By Measurement Frequency= Fair Value Measurements Recurring; Investment Type= Trading Assets Excluding Debt And Equity Securities;
0001628280-25-020465	20241231	Catastrophe Bonds Fair Value Disclosure	0.0000	USD	0	0001628280-25-020465	Fair Value By Fair Value Hierarchy Level= Fair Value Inputs Level3; Fair Value By Measurement Frequency= Fair Value Measurements Recurring; Investment Type= Trading Assets Excluding Debt And Equity Securities;
0001628280-25-020465	20221231	Debt Securities Gain Loss	-400000.0000	USD	4	us-gaap/2024	Related Party Transaction= Class A B Notes;
0001628280-25-020465	20241231	Deferred Policy Acquisition Cost Amortization Expense	420200000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20241231	Deferred Policy Acquisition Cost Amortization Expense	227000000.0000	USD	4	us-gaap/2024	Business Segments= Reinsurance; Consolidation Items= Operating Segments;
0001628280-25-020465	20221231	Deferred Policy Acquisition Costs	319000000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20231231	Deferred Policy Acquisition Costs	296200000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20231231	Depreciation Amortization And Accretion Net	11000000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20241231	Derivative Assets	17000000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20231231	Derivative Liabilities	25800000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20241231	Derivative Liabilities	49500000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20240630	Dividends	6669300.0000	USD	1	us-gaap/2024	Class Of Stock= Series D Preferred Stock;
0001628280-25-020465	20240630	Dividends	3516000.0000	USD	1	us-gaap/2024	Class Of Stock= Series E Preferred Stock;
0001628280-25-020465	20240630	Dividends	3515600.0000	USD	1	us-gaap/2024	Class Of Stock= Series F Preferred Stock;
0001628280-25-020465	20221231	Equity Method Investments	200000.0000	USD	0	us-gaap/2024	Schedule Of Equity Method Investment Equity Method Investee Name= Digital Risk;
0001628280-25-020465	20231231	Equity Method Investments	1000000.0000	USD	0	us-gaap/2024	Schedule Of Equity Method Investment Equity Method Investee Name= M V I;
0001628280-25-020465	20241231	Equity Method Investments	7300000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20241231	Equity Method Investments	6500000.0000	USD	0	us-gaap/2024	Schedule Of Equity Method Investment Equity Method Investee Name= Multi Line Reinsurer;
0001628280-25-020465	20231231	Finance Lease Right Of Use Asset Amortization	500000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020465	20231231	Gain Loss On Sale Of Derivatives	14000000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20241231	Gain Loss On Sale Of Derivatives	6500000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	General And Administrative Expense	233900000.0000	USD	4	us-gaap/2024	Business Segments= Insurance; Consolidation Items= Operating Segments;
0001628280-25-020465	20221231	Income Tax Expense Benefit	-78100000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20241231	Income Tax Expense Benefit	4500000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020465	20231231	Increase Decrease In Deferred Policy Acquisition Costs	-22800000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20221231	Increase Decrease In Other Operating Assets	24400000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20241231	Increase Decrease In Other Operating Assets	3800000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20221231	Increase Decrease In Prepaid Reinsurance Premiums	141200000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20241231	Increase Decrease In Unearned Premiums	219500000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20241231	Intangible Assets Net Including Goodwill	19900000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20221231	Interest Expense Debt	43700000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20241231	Interest Expense Debt	62100000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20221231	Liability For Claims And Claims Adjustment Expense	7710900000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20241231	Liability For Claims And Claims Adjustment Expense	8122600000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20241231	Liability For Claims And Claims Adjustment Expense	61200000.0000	USD	0	us-gaap/2024	Product Or Service= Other Longduration Insurance Product Line;
0001628280-25-020465	20221231	Net Cash Provided By Used In Financing Activities	-84600000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020465	20231231	Net Cash Provided By Used In Financing Activities	-90200000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020465	20231231	Net Cash Provided By Used In Investing Activities	-107400000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020465	20241231	Net Cash Provided By Used In Investing Activities	41000000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020465	20231231	Net Income Loss From Continuing Operations Available To Common Shareholders Basic	484800000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20221231	Net Investment Income	4900000.0000	USD	4	us-gaap/2024	Related Party Transaction= Asset Management Arrangement;
0001628280-25-020465	20221231	Net Investment Income	0.0000	USD	4	us-gaap/2024	Related Party Transactions By Related Party= C L Os;
0001628280-25-020465	20221231	Net Investment Income	0.0000	USD	4	us-gaap/2024	Related Party Transactions By Related Party= Middle Market Term Loans;
0001628280-25-020465	20231231	Net Investment Income	19600000.0000	USD	4	us-gaap/2024	Related Party Transactions By Related Party= Management Consulting Agreement;
0001628280-25-020465	20241231	Net Investment Income	9200000.0000	USD	4	us-gaap/2024	Related Party Transaction= Asset Management Arrangement;
0001628280-25-020465	20221231	Operating Lease Impairment Loss	-6700000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20241231	Other Assets	590800000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20241231	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax	29400000.0000	USD	4	us-gaap/2024	Equity Components= Accumulated Net Unrealized Investment Gain Loss;
0001628280-25-020465	20231231	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Before Tax	-14000000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20241231	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Before Tax	-6500000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20221231	Other Comprehensive Income Loss Net Of Tax	-383300000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20241231	Other Comprehensive Income Loss Net Of Tax	10200000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020465	20241231	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax	-25300000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20241231	Other Investments	78600000.0000	USD	0	us-gaap/2024	Fair Value By Measurement Frequency= Fair Value Measurements Recurring; Related Party Transaction= Apollo Real Estate Fund;
0001628280-25-020465	20241231	Other Investments	78600000.0000	USD	0	us-gaap/2024	Fair Value By Measurement Frequency= Fair Value Measurements Recurring; Related Party Transactions By Related Party= Funds Managed By Apollo;
0001628280-25-020465	20231231	Paymentsfor Proceedsfrom Investing Activities Netof Cash	-4900000.0000	USD	4	0001628280-25-020465
0001628280-25-020465	20241231	Payments For Proceeds From Productive Assets	17500000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Payments To Acquire Equity Method Investments	0.0000	USD	4	us-gaap/2024	Schedule Of Equity Method Investment Equity Method Investee Name= M V I;
0001628280-25-020465	20241231	Payments To Acquire Privately Held Investments Trading	57000000.0000	USD	4	0001628280-25-020465
0001628280-25-020465	20221231	Policyholder Benefits And Claims Incurred Net	1680000000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20221231	Policyholder Benefits And Claims Incurred Net	770300000.0000	USD	4	us-gaap/2024	Business Segments= Reinsurance; Consolidation Items= Operating Segments;
0001628280-25-020465	20231231	Policyholder Benefits And Claims Incurred Net	941900000.0000	USD	4	us-gaap/2024	Business Segments= Insurance; Consolidation Items= Operating Segments;
0001628280-25-020465	20231231	Policyholder Benefits And Claims Incurred Net	611100000.0000	USD	4	us-gaap/2024	Business Segments= Reinsurance; Consolidation Items= Operating Segments;
0001628280-25-020465	20130430	Preferred Stock Issuance Cost	4400000.0000	USD	0	0001628280-25-020465	Class Of Stock= Series D Preferred Stock;
0001628280-25-020465	20160930	Preferred Stock Shares Issued	10000000.0000	shares	0	us-gaap/2024	Class Of Stock= Series E Preferred Stock;
0001628280-25-020465	20231231	Preferred Stock Shares Issued	11000000.0000	shares	0	us-gaap/2024	Class Of Stock= Series D Preferred Stock;
0001628280-25-020465	20231231	Preferred Stock Value	753500000.0000	USD	0	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020465	20241231	Preferred Stock Value	970500000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20231231	Premiums Earned Net	2614500000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Premiums Earned Net	1154500000.0000	USD	4	us-gaap/2024	Business Segments= Reinsurance; Consolidation Items= Operating Segments;
0001628280-25-020465	20241231	Privately Held Investments Amortized Cost Trading At Fair Value	288000000.0000	USD	0	0001628280-25-020465
0001628280-25-020465	20221231	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities	7800000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020465	20231231	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities	474000000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20241231	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities	10300000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020465	20221231	Proceeds From Term Loan Facility	0.0000	USD	4	0001628280-25-020465	Equity Components= Parent;
0001628280-25-020465	20231231	Purchases Of Privately Held Investments Available For Sale	14700000.0000	USD	4	0001628280-25-020465
0001628280-25-020465	20231231	Reclassification From Accumulated Other Comprehensive Income Current Period Before Tax	-40200000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Repayments Of Short Term Debt	300000000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020465	20241231	Repayments Of Short Term Debt	0.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020465	20241231	Selling General And Administrative Expense	-900000.0000	USD	4	us-gaap/2024	Equity Components= Accumulated Gain Loss Cash Flow Hedge Including Noncontrolling Interest; Reclassification Out Of Accumulated Other Comprehensive Income= Reclassification Out Of Accumulated Other Comprehensive Income;
0001628280-25-020465	20241231	Short Term Investments Trading Amortized Cost	1000000.0000	USD	0	0001628280-25-020465
0001628280-25-020465	20231231	Short Term Investments Trading At Fair Value	2100000.0000	USD	0	0001628280-25-020465
0001628280-25-020465	20211231	Stockholders Equity Including Portion Attributable To Noncontrolling Interest	753500000.0000	USD	0	us-gaap/2024	Equity Components= Preferred Stock;
0001628280-25-020465	20221231	Stockholders Equity Including Portion Attributable To Noncontrolling Interest	13800000.0000	USD	0	us-gaap/2024	Equity Components= Accumulated Gain Loss Cash Flow Hedge Including Noncontrolling Interest;
0001628280-25-020465	20221231	Stockholders Equity Including Portion Attributable To Noncontrolling Interest	761700000.0000	USD	0	us-gaap/2024	Equity Components= Additional Paid In Capital;
0001628280-25-020465	20130430	Stock Issued During Period Value New Issues	270600000.0000	USD	0	us-gaap/2024	Class Of Stock= Series D Preferred Stock;
0001628280-25-020465	20241130	Stock Issued During Period Value New Issues	217000000.0000	USD	0	us-gaap/2024	Class Of Stock= Series G Preferred Stock;
0001628280-25-020465	20241231	Derivative Assets	0.0000	USD	0	us-gaap/2024	Derivative Instrument Risk= Foreign Exchange Contract; Fair Value By Asset Class= Derivative Financial Instruments Assets; Fair Value By Fair Value Hierarchy Level= Fair Value Inputs Level3; Fair Value By Measurement Frequency= Fair Value Measurements Recurring;
0001628280-25-020465	20231231	Derivative Gain Loss On Derivative Net	26100000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20241231	Derivative Gain Loss On Derivative Net	-21100000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Dividends	40300000.0000	USD	4	us-gaap/2024	Class Of Stock= Common Stock; Equity Components= Retained Earnings;
0001628280-25-020465	20240331	Dividends	13627200.0000	USD	1	us-gaap/2024
0001628280-25-020465	20241231	Dividends	54948800.0000	USD	4	us-gaap/2024
0001628280-25-020465	20241231	Dividends	26822400.0000	USD	4	us-gaap/2024	Class Of Stock= Series D Preferred Stock;
0001628280-25-020465	20241231	Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents	-8100000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20221231	Equity Method Investments	5200000.0000	USD	0	us-gaap/2024	Schedule Of Equity Method Investment Equity Method Investee Name= Multi Line Reinsurer;
0001628280-25-020465	20241231	Fixed Income Debt Securities Trading	1199900000.0000	USD	0	0001628280-25-020465
0001628280-25-020465	20241231	Fixed Income Debt Securities Trading Amortized Cost	1207700000.0000	USD	0	0001628280-25-020465
0001628280-25-020465	20231231	Gain Loss On Investments	75900000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Income Taxes Paid Net	60900000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20241231	Income Tax Expense Benefit	-22000000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20221231	Increase Decrease In Accrued Liabilities	-87000000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Increase Decrease In Deferred Income Taxes	197700000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20241231	Increase Decrease In Deferred Policy Acquisition Costs	25900000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Increase Decrease In Derivative Instruments	15400000.0000	USD	4	0001628280-25-020465
0001628280-25-020465	20241231	Increase Decrease In Liability For Claims And Claims Adjustment Expense Reserve	312000000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20241231	Increase Decrease In Premiums Receivable	181700000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Increase Decrease In Reinsurance Payables	-563500000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Insurance Reserves	10236900000.0000	USD	0	0001628280-25-020465
0001628280-25-020465	20231231	Interest Expense Debt	55200000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Liability For Claims And Claims Adjustment Expense	1373100000.0000	USD	0	us-gaap/2024	Business Segments= Reinsurance;
0001628280-25-020465	20241231	Liability For Claims And Claims Adjustment Expense	2259100000.0000	USD	0	us-gaap/2024	Business Segments= Insurance;
0001628280-25-020465	20241231	Liability For Claims And Claims Adjustment Expense	1691500000.0000	USD	0	us-gaap/2024	Business Segments= Reinsurance;
0001628280-25-020465	20241231	Net Cash Provided By Used In Financing Activities	-307900000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020465	20221231	Net Cash Provided By Used In Investing Activities	-196500000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Net Cash Provided By Used In Operating Activities	196700000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020465	20241231	Net Income Loss From Continuing Operations Available To Common Shareholders Basic	431200000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20241231	Net Investment Income	318000000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20221231	Operating Lease Payments	15500000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Operating Lease Payments	500000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020465	20241231	Operating Lease Payments	500000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020465	20231231	Operating Lease Right Of Use Asset	61600000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20241231	Other Assets	44700000.0000	USD	0	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020465	20231231	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax	105600000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax	14000000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20241231	Other Expenses	3900000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020465	20231231	Other Income	0.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Other Investments	209300000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20241231	Other Investments	267200000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20241231	Payments For Repurchase Of Preferred Stock And Preference Stock	275000000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20221231	Payments To Acquire Available For Sale Securities Debt	1613900000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20221231	Payments To Acquire Equity Method Investments	400000.0000	USD	4	us-gaap/2024	Schedule Of Equity Method Investment Equity Method Investee Name= M V I;
0001628280-25-020465	20231231	Payments To Acquire Trading Securities Heldforinvestment	418500000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20241130	Preferred Stock Dividend Rate Percentage	0.0700	pure	0	us-gaap/2024	Class Of Stock= Series G Preferred Stock;
0001628280-25-020465	20241231	Preferred Stock Dividend Rate Percentage	0.0595	pure	4	us-gaap/2024	Class Of Stock= Series D Preferred Stock;
0001628280-25-020465	20160930	Preferred Stock Issuance Cost	8700000.0000	USD	0	0001628280-25-020465	Class Of Stock= Series E Preferred Stock;
0001628280-25-020465	20190731	Preferred Stock Issuance Cost	8400000.0000	USD	0	0001628280-25-020465	Class Of Stock= Series F Preferred Stock;
0001628280-25-020465	20241231	Preferred Stock Issuance Cost	29500000.0000	USD	4	0001628280-25-020465
0001628280-25-020465	20160930	Preferred Stock Liquidation Preference Value	250000000.0000	USD	0	us-gaap/2024	Class Of Stock= Series E Preferred Stock;
0001628280-25-020465	20190731	Preferred Stock Liquidation Preference Value	250000000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20241231	Preferred Stock Shares Issued	10000000.0000	shares	0	us-gaap/2024	Class Of Stock= Series E Preferred Stock;
0001628280-25-020465	20221231	Premiums Earned Net	1251800000.0000	USD	4	us-gaap/2024	Business Segments= Reinsurance; Consolidation Items= Operating Segments;
0001628280-25-020465	20231231	Premiums Earned Net	1460000000.0000	USD	4	us-gaap/2024	Business Segments= Insurance; Consolidation Items= Operating Segments;
0001628280-25-020465	20241231	Premiums Earned Net	2889700000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Prepaid Reinsurance Premiums	733500000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20241231	Privatelyheld Investments	286800000.0000	USD	0	0001628280-25-020465
0001628280-25-020465	20241231	Privatelyheld Investments	73600000.0000	USD	0	0001628280-25-020465	Fair Value By Measurement Frequency= Fair Value Measurements Recurring; Related Party Transactions By Related Party= Apollo Originating Partnership;
0001628280-25-020465	20231231	Privately Held Investments Available For Sale At Fair Value	14900000.0000	USD	0	0001628280-25-020465
0001628280-25-020465	20241231	Privately Held Investments Available For Sale At Fair Value	24200000.0000	USD	0	0001628280-25-020465	Fair Value By Measurement Frequency= Fair Value Measurements Recurring; Investment Type= Privately Held Investments Available For Sale;
0001628280-25-020465	20221231	Proceeds From Issuance Of Preferred Stock And Preference Stock	0.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Proceeds From Issuance Of Preferred Stock And Preference Stock	0.0000	USD	4	us-gaap/2024
0001628280-25-020465	20221231	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities	293600000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Proceeds From Sale Of Available For Sale Securities Debt	1326700000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20241231	Proceeds From Sale Of Available For Sale Securities Debt	1872700000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20221231	Proceeds From Sale Of Short Term Investments	2600000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Proceeds From Sale Of Short Term Investments	19500000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20221231	Profit Loss	51100000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020465	20241231	Profit Loss	486100000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20241231	Profit Loss	47900000.0000	USD	4	us-gaap/2024	Equity Components= Accumulated Net Investment Gain Loss Including Portion Attributable To Noncontrolling Interest; Reclassification Out Of Accumulated Other Comprehensive Income= Reclassification Out Of Accumulated Other Comprehensive Income;
0001628280-25-020465	20231231	Purchases Of Proceeds From Catastrophe Bonds	-1500000.0000	USD	4	0001628280-25-020465
0001628280-25-020465	20241231	Redeemable Preferred Stock Dividends	54900000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20221231	Revenues	2890000000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20221231	Revenues	132900000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020465	20211231	Stockholders Equity Including Portion Attributable To Noncontrolling Interest	761700000.0000	USD	0	us-gaap/2024	Equity Components= Additional Paid In Capital;
0001628280-25-020465	20211231	Stockholders Equity Including Portion Attributable To Noncontrolling Interest	1382500000.0000	USD	0	us-gaap/2024	Equity Components= Retained Earnings;
0001628280-25-020465	20221231	Stockholders Equity Including Portion Attributable To Noncontrolling Interest	753500000.0000	USD	0	us-gaap/2024	Equity Components= Preferred Stock;
0001628280-25-020465	20221231	Stockholders Equity Including Portion Attributable To Noncontrolling Interest	1349000000.0000	USD	0	us-gaap/2024	Equity Components= Retained Earnings;
0001628280-25-020465	20231231	Stockholders Equity Including Portion Attributable To Noncontrolling Interest	753500000.0000	USD	0	us-gaap/2024	Equity Components= Preferred Stock;
0001628280-25-020465	20241231	Unearned Premiums	2645800000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20241231	Unrealized Gainloss On Real Estate Fund In Net Investment Income	-6100000.0000	USD	4	0001628280-25-020465
0001628280-25-020463	20241231	Accrued Liabilities Current And Noncurrent	237200000.0000	USD	0	us-gaap/2024		Includes amounts due to related parties of $4.0 million for investment management fees (2023 $2.1 million), and $1.3 million for management consulting fees (2023 $1.2 million).
0001628280-25-020463	20241231	Accrued Liabilities Current And Noncurrent	1300000.0000	USD	0	us-gaap/2024	Related Party Transactions By Related Party= Management Consulting Agreement;
0001628280-25-020463	20221231	Accumulated Other Comprehensive Income Loss Net Of Tax	-506300000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20241231	Cash And Cash Equivalents At Carrying Value	914200000.0000	USD	0	us-gaap/2024		Cash and cash equivalents includes restricted cash of $181.9 million (2023 $323.2 million) which are held in trusts.
0001628280-25-020463	20231231	Catastrophe Bonds Fair Value Disclosure	1600000.0000	USD	0	0001628280-25-020463	Fair Value By Fair Value Hierarchy Level= Fair Value Inputs Level2; Fair Value By Measurement Frequency= Fair Value Measurements Recurring; Investment Type= Trading Assets Excluding Debt And Equity Securities;
0001628280-25-020463	20231231	Common Stock Value	100000.0000	USD	0	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20231231	Deferred Income Tax Assets Net	312600000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20221231	Deferred Policy Acquisition Costs	319000000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20231231	Derivative Assets	0.0000	USD	0	us-gaap/2024	Derivative Instrument Risk= Foreign Exchange Contract; Fair Value By Asset Class= Derivative Financial Instruments Assets; Fair Value By Fair Value Hierarchy Level= Fair Value Inputs Level1; Fair Value By Measurement Frequency= Fair Value Measurements Recurring;
0001628280-25-020463	20221231	Dividends	40000000.0000	USD	4	us-gaap/2024	Class Of Stock= Common Stock; Equity Components= Retained Earnings;
0001628280-25-020463	20240930	Dividends	6741900.0000	USD	1	us-gaap/2024	Class Of Stock= Series D Preferred Stock;
0001628280-25-020463	20240930	Dividends	3516000.0000	USD	1	us-gaap/2024	Class Of Stock= Series E Preferred Stock;
0001628280-25-020463	20241231	Equity Method Investments	7300000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20221231	Expense	2917000000.0000	USD	4	0001628280-25-020463
0001628280-25-020463	20231231	Expense	2563500000.0000	USD	4	0001628280-25-020463
0001628280-25-020463	20221231	Finance Lease Right Of Use Asset Amortization	10100000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20241231	Fixed Income Debt Securities Available For Sale Allowance For Credit Loss	1000000.0000	USD	0	0001628280-25-020463
0001628280-25-020463	20241231	Foreign Currency Transaction Gain Loss Before Tax	60200000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20241231	Gain Loss On Investments	400000.0000	USD	4	us-gaap/2024	Related Party Transaction= Apollo Real Estate Fund;
0001628280-25-020463	20221231	Income Tax Expense Benefit	0.0000	USD	4	us-gaap/2024	Equity Components= Accumulated Net Investment Gain Loss Including Portion Attributable To Noncontrolling Interest; Reclassification Out Of Accumulated Other Comprehensive Income= Reclassification Out Of Accumulated Other Comprehensive Income;
0001628280-25-020463	20231231	Income Tax Expense Benefit	6600000.0000	USD	4	us-gaap/2024	Equity Components= Accumulated Net Investment Gain Loss Including Portion Attributable To Noncontrolling Interest; Reclassification Out Of Accumulated Other Comprehensive Income= Reclassification Out Of Accumulated Other Comprehensive Income;
0001628280-25-020465	20241231	Other Expenses	0.0000	USD	4	us-gaap/2024
0001628280-25-020465	20221231	Other Income	8200000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20241231	Income Tax Expense Benefit	200000.0000	USD	4	us-gaap/2024	Equity Components= Accumulated Gain Loss Cash Flow Hedge Including Noncontrolling Interest; Reclassification Out Of Accumulated Other Comprehensive Income= Reclassification Out Of Accumulated Other Comprehensive Income;
0001628280-25-020463	20241231	Increase Decrease In Accrued Income Taxes Payable	-3000000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20231231	Increase Decrease In Accrued Liabilities	13200000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20221231	Increase Decrease In Deferred Income Taxes	104600000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20231231	Increase Decrease In Other Operating Assets	-62200000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20241231	Increase Decrease In Unearned Premiums	219500000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20231231	Interest On Operating Lease Liabilities	4500000.0000	USD	4	0001628280-25-020463
0001628280-25-020463	20241231	Interest On Operating Lease Liabilities	4100000.0000	USD	4	0001628280-25-020463
0001628280-25-020463	20241231	Investments Excluding Derivative Assets	6741500000.0000	USD	0	0001628280-25-020463
0001628280-25-020463	20231231	Liabilities	12316300000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20231231	Liabilities And Stockholders Equity	3382300000.0000	USD	0	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20241231	Liabilities And Stockholders Equity	15748500000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20221231	Liability For Claims And Claims Adjustment Expense	1452500000.0000	USD	0	us-gaap/2024	Business Segments= Insurance;
0001628280-25-020463	20241231	Liability For Claims And Claims Adjustment Expense	61200000.0000	USD	0	us-gaap/2024	Product Or Service= Other Longduration Insurance Product Line;
0001628280-25-020463	20241231	Net Cash Provided By Used In Financing Activities	-307900000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20241231	Net Cash Provided By Used In Operating Activities	554900000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20231231	Net Changein Receivablefor Securities Soldor Payablefor Securities Purchased	19900000.0000	USD	4	0001628280-25-020463
0001628280-25-020463	20221231	Net Income Loss	51100000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20221231	Net Investment Income	3100000.0000	USD	4	us-gaap/2024	Related Party Transactions By Related Party= Management Consulting Agreement;
0001628280-25-020463	20241231	Net Investment Income	11300000.0000	USD	4	us-gaap/2024	Related Party Transactions By Related Party= C L Os;
0001628280-25-020463	20241231	Net Investment Income	500000.0000	USD	4	us-gaap/2024	Related Party Transactions By Related Party= Middle Market Term Loans;
0001628280-25-020463	20221231	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax	-367800000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20221231	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax	-30900000.0000	USD	4	us-gaap/2024	Equity Components= Accumulated Translation Adjustment;
0001628280-25-020463	20241231	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax	29400000.0000	USD	4	us-gaap/2024	Equity Components= Accumulated Net Unrealized Investment Gain Loss;
0001628280-25-020463	20221231	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax Parent	15400000.0000	USD	4	us-gaap/2024	Equity Components= Accumulated Translation Adjustment;
0001628280-25-020463	20221231	Other Comprehensive Income Loss Net Of Tax	-383300000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20241231	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax	-6800000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20221231	Other Expenses	20100000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20221231	Other Income	8200000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20231231	Other Income	3200000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20231231	Other Investments	39800000.0000	USD	0	us-gaap/2024	Fair Value By Measurement Frequency= Fair Value Measurements Recurring; Related Party Transactions By Related Party= Funds Managed By Apollo;
0001628280-25-020463	20221231	Payments For Proceeds From Other Investing Activities	62500000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20241231	Payments For Proceeds From Other Investing Activities	32500000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20231231	Payments To Acquire Available For Sale Securities Debt	1554800000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20231231	Payments To Acquire Equity Method Investments	400000.0000	USD	4	us-gaap/2024	Schedule Of Equity Method Investment Equity Method Investee Name= Multi Line Reinsurer;
0001628280-25-020463	20231231	Payments To Acquire Equity Method Investments	0.0000	USD	4	us-gaap/2024	Schedule Of Equity Method Investment Equity Method Investee Name= M V I;
0001628280-25-020463	20241231	Payments To Acquire Equity Method Investments	0.0000	USD	4	us-gaap/2024
0001628280-25-020463	20231231	Payments To Acquire Privately Held Investments Trading	99000000.0000	USD	4	0001628280-25-020463
0001628280-25-020463	20241231	Payments To Acquire Short Term Investments	5700000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20221231	Payments To Acquire Trading Securities Heldforinvestment	724600000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20241231	Policyholder Benefits And Claims Incurred Net	976500000.0000	USD	4	us-gaap/2024	Business Segments= Insurance; Consolidation Items= Operating Segments;
0001628280-25-020463	20130430	Preferred Stock Dividend Rate Percentage	0.0595	pure	0	us-gaap/2024	Class Of Stock= Series D Preferred Stock;
0001628280-25-020463	20241231	Preferred Stock Dividend Rate Percentage	0.0595	pure	0	us-gaap/2024	Class Of Stock= Series D Preferred Stock; Subsequent Event Type= Subsequent Event;
0001628280-25-020463	20250228	Preferred Stock Dividend Rate Percentage	0.0563	pure	0	us-gaap/2024	Class Of Stock= Series F Preferred Stock; Subsequent Event Type= Subsequent Event;
0001628280-25-020463	20231231	Preferred Stock Shares Issued	10000000.0000	shares	0	us-gaap/2024	Class Of Stock= Series E Preferred Stock;
0001628280-25-020463	20241231	Premiums Earned Net	1584000000.0000	USD	4	us-gaap/2024	Business Segments= Insurance;
0001628280-25-020463	20231231	Privatelyheld Investments	112400000.0000	USD	0	0001628280-25-020463	Fair Value By Measurement Frequency= Fair Value Measurements Recurring; Related Party Transactions By Related Party= Apollo Originating Partnership;
0001628280-25-020463	20231231	Privatelyheld Investments	82200000.0000	USD	0	0001628280-25-020463	Fair Value By Measurement Frequency= Fair Value Measurements Recurring; Related Party Transactions By Related Party= Apollo S P V;
0001628280-25-020463	20241231	Privatelyheld Investments	286800000.0000	USD	0	0001628280-25-020463
0001628280-25-020463	20241231	Privately Held Investments Available For Sale At Fair Value	24200000.0000	USD	0	0001628280-25-020463	Fair Value By Fair Value Hierarchy Level= Fair Value Inputs Level3; Fair Value By Measurement Frequency= Fair Value Measurements Recurring; Investment Type= Privately Held Investments Available For Sale;
0001628280-25-020463	20221231	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities	7800000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20221231	Profit Loss	51100000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20221231	Profit Loss	51100000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20231231	Profit Loss	33600000.0000	USD	4	us-gaap/2024	Equity Components= Accumulated Net Investment Gain Loss Including Portion Attributable To Noncontrolling Interest; Reclassification Out Of Accumulated Other Comprehensive Income= Reclassification Out Of Accumulated Other Comprehensive Income;
0001628280-25-020463	20231231	Reclassification From Accumulated Other Comprehensive Income Current Period Before Tax	-40200000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20241231	Reclassification From Accumulated Other Comprehensive Income Current Period Before Tax	-59400000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20221231	Reclassification From Aoci Current Period Tax	0.0000	USD	4	us-gaap/2024
0001628280-25-020463	20231231	Reclassification From Aoci Current Period Tax	-6600000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20221231	Redeemable Preferred Stock Dividends	44600000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20231231	Redeemable Preferred Stock Dividends	49900000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20221231	Repayments Of Short Term Debt	0.0000	USD	4	us-gaap/2024
0001628280-25-020463	20231231	Repayments Of Short Term Debt	300000000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20231231	Short Term Investments Trading At Fair Value	2100000.0000	USD	0	0001628280-25-020463
0001628280-25-020463	20231231	Stockholders Equity Including Portion Attributable To Noncontrolling Interest	-172500000.0000	USD	0	us-gaap/2024	Equity Components= Accumulated Translation Adjustment;
0001628280-25-020463	20241231	Stockholders Equity Including Portion Attributable To Noncontrolling Interest	761700000.0000	USD	0	us-gaap/2024	Equity Components= Additional Paid In Capital;
0001628280-25-020463	20160930	Stock Issued During Period Value New Issues	241300000.0000	USD	0	us-gaap/2024	Class Of Stock= Series E Preferred Stock;
0001628280-25-020463	20241130	Stock Issued During Period Value New Issues	217000000.0000	USD	0	us-gaap/2024	Class Of Stock= Series G Preferred Stock;
0001628280-25-020465	20241231	Accrued Liabilities Current And Noncurrent	1300000.0000	USD	0	us-gaap/2024	Related Party Transactions By Related Party= Management Consulting Agreement;
0001628280-25-020465	20221231	Accumulated Other Comprehensive Income Loss Net Of Tax	-506300000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20241231	Aggregate Liquidation Preference Shares	1000000000.0000	USD	4	0001628280-25-020465
0001628280-25-020465	20241231	Cash And Cash Equivalents Includes Restricted Cash	181900000.0000	USD	0	0001628280-25-020465
0001628280-25-020465	20221231	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect	-354900000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20241231	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect	-113900000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Common Stock Value	100000.0000	USD	0	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020465	20231231	Comprehensive Income Net Of Tax	640700000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020465	20231231	Deferred Income Tax Assets Net	312600000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20241231	Deferred Income Tax Liabilities Net	1100000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20221231	Deferred Policy Acquisition Cost Amortization Expense	179400000.0000	USD	4	us-gaap/2024	Business Segments= Insurance; Consolidation Items= Operating Segments;
0001628280-25-020465	20231231	Deferred Policy Acquisition Cost Amortization Expense	380200000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Deferred Policy Acquisition Cost Amortization Expense	208600000.0000	USD	4	us-gaap/2024	Business Segments= Reinsurance; Consolidation Items= Operating Segments;
0001628280-25-020465	20231231	Derivative Assets	0.0000	USD	0	us-gaap/2024	Derivative Instrument Risk= Foreign Exchange Contract; Fair Value By Asset Class= Derivative Financial Instruments Assets; Fair Value By Fair Value Hierarchy Level= Fair Value Inputs Level1; Fair Value By Measurement Frequency= Fair Value Measurements Recurring;
0001628280-25-020465	20221231	Dividends	40000000.0000	USD	4	us-gaap/2024	Class Of Stock= Common Stock; Equity Components= Retained Earnings;
0001628280-25-020465	20240930	Dividends	13773500.0000	USD	1	us-gaap/2024
0001628280-25-020465	20240930	Dividends	3516000.0000	USD	1	us-gaap/2024	Class Of Stock= Series E Preferred Stock;
0001628280-25-020465	20240930	Dividends	3515600.0000	USD	1	us-gaap/2024	Class Of Stock= Series F Preferred Stock;
0001628280-25-020465	20241231	Dividends	195000000.0000	USD	4	us-gaap/2024	Class Of Stock= Common Stock; Equity Components= Retained Earnings;
0001628280-25-020465	20241231	Dividends	14064000.0000	USD	4	us-gaap/2024	Class Of Stock= Series E Preferred Stock;
0001628280-25-020465	20231231	Equity Method Investments	6400000.0000	USD	0	us-gaap/2024	Schedule Of Equity Method Investment Equity Method Investee Name= Multi Line Reinsurer;
0001628280-25-020465	20241231	Equity Method Investments	800000.0000	USD	0	us-gaap/2024	Schedule Of Equity Method Investment Equity Method Investee Name= M V I;
0001628280-25-020465	20231231	Expense	2563500000.0000	USD	4	0001628280-25-020465
0001628280-25-020465	20241231	Expense	2796200000.0000	USD	4	0001628280-25-020465
0001628280-25-020465	20221231	Finance Lease Right Of Use Asset Amortization	10100000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20241231	Fixed Income Debt Securities Available For Sale Allowance For Credit Loss	1000000.0000	USD	0	0001628280-25-020465
0001628280-25-020465	20241231	General And Administrative Expense	405900000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20241231	General And Administrative Expense	5000000.0000	USD	4	us-gaap/2024	Related Party Transaction= Management Consulting Agreement;
0001628280-25-020465	20221231	Income Tax Expense Benefit	0.0000	USD	4	us-gaap/2024	Equity Components= Accumulated Net Investment Gain Loss Including Portion Attributable To Noncontrolling Interest; Reclassification Out Of Accumulated Other Comprehensive Income= Reclassification Out Of Accumulated Other Comprehensive Income;
0001628280-25-020465	20231231	Income Tax Expense Benefit	6600000.0000	USD	4	us-gaap/2024	Equity Components= Accumulated Net Investment Gain Loss Including Portion Attributable To Noncontrolling Interest; Reclassification Out Of Accumulated Other Comprehensive Income= Reclassification Out Of Accumulated Other Comprehensive Income;
0001628280-25-020465	20241231	Increase Decrease In Accrued Income Taxes Payable	-3000000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Increase Decrease In Accrued Liabilities	13200000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20221231	Interest On Operating Lease Liabilities	5400000.0000	USD	4	0001628280-25-020465
0001628280-25-020465	20241231	Interest On Operating Lease Liabilities	4100000.0000	USD	4	0001628280-25-020465
0001628280-25-020465	20231231	Liabilities	12316300000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20231231	Liabilities And Stockholders Equity	3382300000.0000	USD	0	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020465	20241231	Liabilities And Stockholders Equity	15748500000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20241231	Net Cash Provided By Used In Financing Activities	-307900000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20221231	Net Cash Provided By Used In Operating Activities	-55000000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Net Cash Provided By Used In Operating Activities	324700000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20241231	Net Cash Provided By Used In Operating Activities	554900000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20221231	Net Income Loss	51100000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20221231	Net Investment Income	188100000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20241231	Net Investment Income	11300000.0000	USD	4	us-gaap/2024	Related Party Transactions By Related Party= C L Os;
0001628280-25-020465	20241231	Net Investment Income	500000.0000	USD	4	us-gaap/2024	Related Party Transactions By Related Party= Middle Market Term Loans;
0001628280-25-020465	20221231	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax	-30900000.0000	USD	4	us-gaap/2024	Equity Components= Accumulated Translation Adjustment;
0001628280-25-020465	20241231	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax	29400000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20221231	Other Comprehensive Income Loss Net Of Tax	-383300000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020465	20241231	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax	-6800000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20221231	Other Expenses	20100000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20221231	Other Expenses	4800000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020465	20231231	Other Expenses	1800000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020465	20231231	Other Investments	39800000.0000	USD	0	us-gaap/2024	Fair Value By Measurement Frequency= Fair Value Measurements Recurring; Related Party Transactions By Related Party= Funds Managed By Apollo;
0001628280-25-020465	20241231	Paymentsfor Availableforsale Securities Shortterm	334700000.0000	USD	4	0001628280-25-020465
0001628280-25-020465	20241231	Payments For Proceeds From Other Investing Activities	32500000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20221231	Payments For Repurchase Of Preferred Stock And Preference Stock	0.0000	USD	4	us-gaap/2024	Equity Components= Parent;
0001628280-25-020465	20221231	Payments Of Dividends Preferred Stock And Preference Stock	44600000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20161231	Payments To Acquire Equity Method Investments	2300000.0000	USD	0	us-gaap/2024	Schedule Of Equity Method Investment Equity Method Investee Name= Digital Risk;
0001628280-25-020465	20231231	Payments To Acquire Equity Method Investments	400000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20241231	Payments To Acquire Short Term Investments	5700000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20221231	Payments To Acquire Trading Securities Heldforinvestment	724600000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Policyholder Benefits And Claims Incurred Net	1553000000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20241231	Policyholder Benefits And Claims Incurred Net	976500000.0000	USD	4	us-gaap/2024	Business Segments= Insurance; Consolidation Items= Operating Segments;
0001628280-25-020465	20130430	Preferred Stock Dividend Rate Percentage	0.0595	pure	0	us-gaap/2024	Class Of Stock= Series D Preferred Stock;
0001628280-25-020465	20250228	Preferred Stock Dividend Rate Percentage	0.0563	pure	0	us-gaap/2024	Class Of Stock= Series F Preferred Stock; Subsequent Event Type= Subsequent Event;
0001628280-25-020465	20221231	Preferred Stock Issuance Cost	21500000.0000	USD	4	0001628280-25-020465
0001628280-25-020465	20241231	Preferred Stock Shares Issued	11000000.0000	shares	0	us-gaap/2024	Class Of Stock= Series D Preferred Stock;
0001628280-25-020465	20221231	Premiums Earned Net	1251800000.0000	USD	4	us-gaap/2024	Business Segments= Reinsurance;
0001628280-25-020465	20231231	Privatelyheld Investments	82200000.0000	USD	0	0001628280-25-020465	Fair Value By Measurement Frequency= Fair Value Measurements Recurring; Related Party Transactions By Related Party= Apollo S P V;
0001628280-25-020465	20231231	Privately Held Investments Available For Sale At Fair Value	14900000.0000	USD	0	0001628280-25-020465	Fair Value By Measurement Frequency= Fair Value Measurements Recurring; Related Party Transactions By Related Party= Apollo Originating Partnership;
0001628280-25-020465	20241231	Privately Held Investments Available For Sale At Fair Value	24200000.0000	USD	0	0001628280-25-020465	Fair Value By Fair Value Hierarchy Level= Fair Value Inputs Level3; Fair Value By Measurement Frequency= Fair Value Measurements Recurring; Investment Type= Privately Held Investments Available For Sale;
0001628280-25-020465	20241231	Proceedsfrom Availableforsale Securities Shortterm	167000000.0000	USD	4	0001628280-25-020465
0001628280-25-020465	20221231	Proceeds From Sale Of Available For Sale Securities Debt	2212500000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20221231	Proceedsfrom Saleof Privatelyheld Investments	147400000.0000	USD	4	0001628280-25-020465
0001628280-25-020465	20231231	Proceedsfrom Saleof Privatelyheld Investments	136900000.0000	USD	4	0001628280-25-020465
0001628280-25-020465	20221231	Profit Loss	51100000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Profit Loss	33600000.0000	USD	4	us-gaap/2024	Equity Components= Accumulated Net Investment Gain Loss Including Portion Attributable To Noncontrolling Interest; Reclassification Out Of Accumulated Other Comprehensive Income= Reclassification Out Of Accumulated Other Comprehensive Income;
0001628280-25-020465	20241231	Reclassification From Accumulated Other Comprehensive Income Current Period Before Tax	-59400000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20221231	Reclassification From Aoci Current Period Tax	0.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Reclassification From Aoci Current Period Tax	-6600000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Redeemable Preferred Stock Dividends	49900000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Repayments Of Short Term Debt	300000000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20241231	Short Term Investments Trading At Fair Value	1000000.0000	USD	0	0001628280-25-020465
0001628280-25-020465	20221231	Stockholders Equity Including Portion Attributable To Noncontrolling Interest	-186900000.0000	USD	0	us-gaap/2024	Equity Components= Accumulated Translation Adjustment;
0001628280-25-020465	20231231	Stockholders Equity Including Portion Attributable To Noncontrolling Interest	-172500000.0000	USD	0	us-gaap/2024	Equity Components= Accumulated Translation Adjustment;
0001628280-25-020465	20231231	Stockholders Equity Including Portion Attributable To Noncontrolling Interest	1793500000.0000	USD	0	us-gaap/2024	Equity Components= Retained Earnings;
0001628280-25-020465	20241231	Stockholders Equity Including Portion Attributable To Noncontrolling Interest	3371900000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20241231	Stockholders Equity Including Portion Attributable To Noncontrolling Interest	-5300000.0000	USD	0	us-gaap/2024	Equity Components= Accumulated Gain Loss Cash Flow Hedge Including Noncontrolling Interest;
0001628280-25-020465	20160930	Stock Issued During Period Value New Issues	241300000.0000	USD	0	us-gaap/2024	Class Of Stock= Series E Preferred Stock;
0001628280-25-020463	20241231	Accounts Payable Current And Noncurrent	36900000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20241231	Accrued Income Taxes Current	6800000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20241231	Accrued Liabilities Current And Noncurrent	20700000.0000	USD	0	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20221231	Income Tax Expense Benefit	-78100000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20241231	Accumulated Other Comprehensive Income Loss Net Of Tax	-390100000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20231231	Additional Paid In Capital	761700000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20231231	Additional Paid In Capital	761700000.0000	USD	0	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20221231	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect	-600000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20231231	Catastrophe Bonds Fair Value Disclosure	0.0000	USD	0	0001628280-25-020463	Fair Value By Fair Value Hierarchy Level= Fair Value Inputs Level1; Fair Value By Measurement Frequency= Fair Value Measurements Recurring; Investment Type= Trading Assets Excluding Debt And Equity Securities;
0001628280-25-020463	20231231	Common Stock Value	91000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20241231	Comprehensive Income Net Of Tax	496300000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20221231	Debt Securities Gain Loss	-182600000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20241231	Deferred Policy Acquisition Cost Amortization Expense	227000000.0000	USD	4	us-gaap/2024	Business Segments= Reinsurance; Consolidation Items= Operating Segments;
0001628280-25-020463	20231231	Derivative Assets	31700000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20241231	Derivative Assets	0.0000	USD	0	us-gaap/2024	Derivative Instrument Risk= Foreign Exchange Contract; Fair Value By Asset Class= Derivative Financial Instruments Assets; Fair Value By Fair Value Hierarchy Level= Fair Value Inputs Level1; Fair Value By Measurement Frequency= Fair Value Measurements Recurring;
0001628280-25-020463	20231231	Derivative Gain Loss On Derivative Net	26100000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20240331	Dividends	13627200.0000	USD	1	us-gaap/2024
0001628280-25-020463	20240630	Dividends	3515600.0000	USD	1	us-gaap/2024	Class Of Stock= Series F Preferred Stock;
0001628280-25-020463	20241231	Dividends	13847200.0000	USD	1	us-gaap/2024
0001628280-25-020463	20241231	Earnings Per Share Basic	4.7500	USD	4	us-gaap/2024
0001628280-25-020463	20231231	Earnings Per Share Diluted	5.3400	USD	4	us-gaap/2024
0001628280-25-020463	20221231	Equity Method Investments	5200000.0000	USD	0	us-gaap/2024	Schedule Of Equity Method Investment Equity Method Investee Name= Multi Line Reinsurer;
0001628280-25-020463	20221231	Equity Method Investments	800000.0000	USD	0	us-gaap/2024	Schedule Of Equity Method Investment Equity Method Investee Name= M V I;
0001628280-25-020463	20231231	Equity Method Investments	7600000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20231231	Equity Method Investments	1000000.0000	USD	0	us-gaap/2024	Schedule Of Equity Method Investment Equity Method Investee Name= M V I;
0001628280-25-020463	20241231	Fixed Income Debt Securities Available For Sale Including Related Party Investments	14000000.0000	USD	0	0001628280-25-020463	Fair Value By Measurement Frequency= Fair Value Measurements Recurring; Related Party Transactions By Related Party= C L Os;
0001628280-25-020463	20221231	Foreign Currency Transaction Gain Loss Before Tax	15900000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20221231	Gain Loss On Investments	3100000.0000	USD	4	us-gaap/2024	Related Party Transaction= Apollo Real Estate Fund;
0001628280-25-020463	20221231	Gain Loss On Sale Of Derivatives	-15400000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20231231	Gain Loss On Sale Of Derivatives	14000000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20241231	Gains Losses On Investment And Foreign Exchange	-11200000.0000	USD	4	0001628280-25-020463
0001628280-25-020463	20221231	General And Administrative Expense	5000000.0000	USD	4	us-gaap/2024	Related Party Transaction= Management Consulting Agreement;
0001628280-25-020463	20241231	General And Administrative Expense	264200000.0000	USD	4	us-gaap/2024	Business Segments= Insurance; Consolidation Items= Operating Segments;
0001628280-25-020463	20221231	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments	55000000.0000	USD	4	us-gaap/2024	Equity Components= Accumulated Net Investment Gain Loss Including Portion Attributable To Noncontrolling Interest; Reclassification Out Of Accumulated Other Comprehensive Income= Reclassification Out Of Accumulated Other Comprehensive Income;
0001628280-25-020463	20221231	Income Tax Expense Benefit	0.0000	USD	4	us-gaap/2024	Equity Components= Accumulated Gain Loss Cash Flow Hedge Including Noncontrolling Interest; Reclassification Out Of Accumulated Other Comprehensive Income= Reclassification Out Of Accumulated Other Comprehensive Income;
0001628280-25-020463	20241231	Increase Decrease In Deferred Income Taxes	88600000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20221231	Increase Decrease In Derivative Instruments	-21700000.0000	USD	4	0001628280-25-020463
0001628280-25-020463	20231231	Increase Decrease In Liability For Claims And Claims Adjustment Expense Reserve	99700000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20231231	Increase Decrease In Unpaid Losses Recoverable From Reinsurers	319900000.0000	USD	4	0001628280-25-020463
0001628280-25-020463	20231231	Intangible Assets Net Including Goodwill	21700000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20231231	Interest Expense Debt	55200000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20221231	Interest Paid	14300000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20241231	Liabilities And Stockholders Equity	3790400000.0000	USD	0	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20241231	Liability For Claims And Claims Adjustment Expense	8122600000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20241231	Net Cash Provided By Used In Operating Activities	266900000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20221231	Net Investment Income	4900000.0000	USD	4	us-gaap/2024	Related Party Transaction= Asset Management Arrangement;
0001628280-25-020463	20231231	Net Investment Income	275700000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20241231	Net Investment Income	15200000.0000	USD	4	us-gaap/2024	Related Party Transactions By Related Party= Management Consulting Agreement;
0001628280-25-020463	20231231	Operating Lease Impairment Loss	0.0000	USD	4	us-gaap/2024
0001628280-25-020463	20231231	Operating Lease Payments	500000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20231231	Operating Lease Right Of Use Asset	1500000.0000	USD	0	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20241231	Other Assets	590800000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20231231	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax	105600000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20231231	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax Parent	-14000000.0000	USD	4	us-gaap/2024	Equity Components= Accumulated Translation Adjustment;
0001628280-25-020463	20221231	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Before Tax	15400000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20231231	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Tax	0.0000	USD	4	us-gaap/2024
0001628280-25-020463	20241231	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Tax	-1400000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20231231	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax	14000000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20241231	Other Investments	267200000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20221231	Paymentsfor Availableforsale Securities Shortterm	55900000.0000	USD	4	0001628280-25-020463
0001628280-25-020463	20241231	Payments To Acquire Equity Method Investments	0.0000	USD	4	us-gaap/2024	Schedule Of Equity Method Investment Equity Method Investee Name= Multi Line Reinsurer;
0001628280-25-020463	20221231	Payments To Acquire Short Term Investments	7000000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20231231	Policyholder Benefits And Claims Incurred Net	611100000.0000	USD	4	us-gaap/2024	Business Segments= Reinsurance; Consolidation Items= Operating Segments;
0001628280-25-020463	20231231	Preferred Stock Dividend Rate Percentage	0.0595	pure	4	us-gaap/2024	Class Of Stock= Series D Preferred Stock;
0001628280-25-020463	20231231	Preferred Stock Dividend Rate Percentage	0.0700	pure	4	us-gaap/2024	Class Of Stock= Series G Preferred Stock;
0001628280-25-020463	20241231	Preferred Stock Dividend Rate Percentage	0.0563	pure	4	us-gaap/2024	Class Of Stock= Series E Preferred Stock;
0001628280-25-020463	20241231	Preferred Stock Dividend Rate Percentage	0.0563	pure	4	us-gaap/2024	Class Of Stock= Series F Preferred Stock;
0001628280-25-020463	20241130	Preferred Stock Liquidation Preference Value	225000000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20241130	Preferred Stock Shares Issued	9000000.0000	shares	0	us-gaap/2024	Class Of Stock= Series G Preferred Stock;
0001628280-25-020463	20241231	Preferred Stock Shares Issued	9000000.0000	shares	0	us-gaap/2024	Class Of Stock= Series G Preferred Stock;
0001628280-25-020463	20231231	Premiums Earned Net	2614500000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20231231	Premiums Earned Net	1460000000.0000	USD	4	us-gaap/2024	Business Segments= Insurance;
0001628280-25-020463	20231231	Privately Held Investments Amortized Cost Trading At Fair Value	494900000.0000	USD	0	0001628280-25-020463
0001628280-25-020463	20241231	Privately Held Investments Amortized Cost Trading At Fair Value	288000000.0000	USD	0	0001628280-25-020463
0001628280-25-020463	20231231	Privately Held Investments Available For Sale At Fair Value	14900000.0000	USD	0	0001628280-25-020463	Fair Value By Fair Value Hierarchy Level= Fair Value Inputs Level3; Fair Value By Measurement Frequency= Fair Value Measurements Recurring; Financial Instrument= Trading Assets Excluding Debt And Equity Securities;
0001628280-25-020463	20231231	Proceedsfrom Availableforsale Securities Shortterm	231000000.0000	USD	4	0001628280-25-020463
0001628280-25-020463	20241231	Proceeds From Issuance Of Preferred Stock And Preference Stock	217000000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20231231	Proceeds From Term Loan Facility	300000000.0000	USD	4	0001628280-25-020463
0001628280-25-020463	20241231	Profit Loss	486100000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20241231	Profit Loss	47900000.0000	USD	4	us-gaap/2024	Equity Components= Accumulated Net Investment Gain Loss Including Portion Attributable To Noncontrolling Interest; Reclassification Out Of Accumulated Other Comprehensive Income= Reclassification Out Of Accumulated Other Comprehensive Income;
0001628280-25-020463	20221231	Purchases Of Privately Held Investments Available For Sale	0.0000	USD	4	0001628280-25-020463
0001628280-25-020463	20231231	Reinsurance Recoverables Allowance	3700000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20231231	Reinsurance Recoverables On Paid And Unpaid Losses	4577800000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20231231	Retained Earnings Accumulated Deficit	1793500000.0000	USD	0	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20231231	Selling General And Administrative Expense	8100000.0000	USD	4	us-gaap/2024	Equity Components= Accumulated Gain Loss Cash Flow Hedge Including Noncontrolling Interest; Reclassification Out Of Accumulated Other Comprehensive Income= Reclassification Out Of Accumulated Other Comprehensive Income;
0001628280-25-020463	20241231	Selling General And Administrative Expense	533100000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20231231	Shortterminvestmentsavailableforsaleamortizedcost	93600000.0000	USD	0	0001628280-25-020463
0001628280-25-020463	20211231	Stockholders Equity Including Portion Attributable To Noncontrolling Interest	100000.0000	USD	0	us-gaap/2024	Equity Components= Common Stock;
0001628280-25-020463	20231231	Stockholders Equity Including Portion Attributable To Noncontrolling Interest	2908500000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20130430	Stock Issued During Period Value New Issues	270600000.0000	USD	0	us-gaap/2024	Class Of Stock= Series D Preferred Stock;
0001628280-25-020465	20241231	Accounts Payable Current And Noncurrent	36900000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20241231	Accrued Income Taxes Current	6800000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20241231	Accumulated Other Comprehensive Income Loss Net Of Tax	-390100000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20231231	Additional Paid In Capital	761700000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20231231	Assets	15224800000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20241231	Cash And Cash Equivalents At Carrying Value	43500000.0000	USD	0	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020465	20231231	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect	68900000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Catastrophe Bonds Fair Value Disclosure	1600000.0000	USD	0	0001628280-25-020465	Fair Value By Fair Value Hierarchy Level= Fair Value Inputs Level2; Fair Value By Measurement Frequency= Fair Value Measurements Recurring; Investment Type= Trading Assets Excluding Debt And Equity Securities;
0001628280-25-020465	20241231	Catastrophe Bonds Fair Value Disclosure	1000000.0000	USD	0	0001628280-25-020465
0001628280-25-020465	20241231	Commitments And Contingencies	0.0000	USD	0	us-gaap/2024
0001628280-25-020465	20231231	Common Stock Value	91000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20241231	Comprehensive Income Net Of Tax	496300000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020465	20231231	Deferred Policy Acquisition Cost Amortization Expense	171600000.0000	USD	4	us-gaap/2024	Business Segments= Insurance; Consolidation Items= Operating Segments;
0001628280-25-020465	20231231	Derivative Assets	31700000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20241231	Derivative Assets	0.0000	USD	0	us-gaap/2024	Derivative Instrument Risk= Foreign Exchange Contract; Fair Value By Asset Class= Derivative Financial Instruments Assets; Fair Value By Fair Value Hierarchy Level= Fair Value Inputs Level1; Fair Value By Measurement Frequency= Fair Value Measurements Recurring;
0001628280-25-020465	20221231	Derivative Gain Loss On Derivative Net	-80500000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20221231	Equity Method Investments	800000.0000	USD	0	us-gaap/2024	Schedule Of Equity Method Investment Equity Method Investee Name= M V I;
0001628280-25-020465	20231231	Equity Method Investments	7600000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20231231	Fixed Income Debt Securities Available For Sale Amortized Cost	4330000000.0000	USD	0	0001628280-25-020465
0001628280-25-020465	20231231	Fixed Income Debt Securities Available For Sale Including Related Party Investments	0.0000	USD	0	0001628280-25-020465	Fair Value By Measurement Frequency= Fair Value Measurements Recurring; Related Party Transactions By Related Party= C L Os;
0001628280-25-020465	20221231	Foreign Currency Transaction Gain Loss Before Tax	15900000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20221231	Gain Loss On Investments	3100000.0000	USD	4	us-gaap/2024	Related Party Transaction= Apollo Real Estate Fund;
0001628280-25-020465	20241231	Gain Loss On Investments	52600000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20221231	Gain Loss On Sale Of Derivatives	-15400000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20241231	Gains Losses On Investment And Foreign Exchange	-11200000.0000	USD	4	0001628280-25-020465
0001628280-25-020465	20231231	General And Administrative Expense	120600000.0000	USD	4	us-gaap/2024	Business Segments= Reinsurance; Consolidation Items= Operating Segments;
0001628280-25-020465	20241231	General And Administrative Expense	264200000.0000	USD	4	us-gaap/2024	Business Segments= Insurance; Consolidation Items= Operating Segments;
0001628280-25-020465	20221231	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments	55000000.0000	USD	4	us-gaap/2024	Equity Components= Accumulated Net Investment Gain Loss Including Portion Attributable To Noncontrolling Interest; Reclassification Out Of Accumulated Other Comprehensive Income= Reclassification Out Of Accumulated Other Comprehensive Income;
0001628280-25-020465	20221231	Income Tax Expense Benefit	0.0000	USD	4	us-gaap/2024	Equity Components= Accumulated Gain Loss Cash Flow Hedge Including Noncontrolling Interest; Reclassification Out Of Accumulated Other Comprehensive Income= Reclassification Out Of Accumulated Other Comprehensive Income;
0001628280-25-020465	20241231	Increase Decrease In Deferred Income Taxes	88600000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20221231	Increase Decrease In Derivative Instruments	-21700000.0000	USD	4	0001628280-25-020465
0001628280-25-020465	20231231	Increase Decrease In Liability For Claims And Claims Adjustment Expense Reserve	99700000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Increase Decrease In Unpaid Losses Recoverable From Reinsurers	319900000.0000	USD	4	0001628280-25-020465
0001628280-25-020465	20231231	Intangible Assets Net Including Goodwill	21700000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20221231	Interest Paid	14300000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20241231	Net Cash Provided By Used In Investing Activities	-352800000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20241231	Net Cash Provided By Used In Operating Activities	266900000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020465	20221231	Net Changein Receivablefor Securities Soldor Payablefor Securities Purchased	-31800000.0000	USD	4	0001628280-25-020465
0001628280-25-020465	20241231	Net Investment Income	15200000.0000	USD	4	us-gaap/2024	Related Party Transactions By Related Party= Management Consulting Agreement;
0001628280-25-020465	20231231	Operating Lease Impairment Loss	0.0000	USD	4	us-gaap/2024
0001628280-25-020465	20241231	Operating Lease Liability	75600000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20241231	Operating Lease Payments	15900000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Operating Lease Right Of Use Asset	1500000.0000	USD	0	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020465	20231231	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax Parent	-14000000.0000	USD	4	us-gaap/2024	Equity Components= Accumulated Translation Adjustment;
0001628280-25-020465	20221231	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Tax	0.0000	USD	4	us-gaap/2024
0001628280-25-020465	20241231	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Tax	-1400000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20221231	Paymentsfor Availableforsale Securities Shortterm	55900000.0000	USD	4	0001628280-25-020465
0001628280-25-020465	20231231	Payments For Repurchase Of Preferred Stock And Preference Stock	0.0000	USD	4	us-gaap/2024
0001628280-25-020465	20221231	Payments To Acquire Short Term Investments	7000000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20241130	Preferred Stock Liquidation Preference Value	225000000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20241130	Preferred Stock Shares Issued	9000000.0000	shares	0	us-gaap/2024	Class Of Stock= Series G Preferred Stock;
0001628280-25-020465	20241231	Preferred Stock Shares Issued	10000000.0000	shares	0	us-gaap/2024	Class Of Stock= Series F Preferred Stock;
0001628280-25-020465	20241231	Preferred Stock Shares Issued	9000000.0000	shares	0	us-gaap/2024	Class Of Stock= Series G Preferred Stock;
0001628280-25-020465	20231231	Premiums Earned Net	1460000000.0000	USD	4	us-gaap/2024	Business Segments= Insurance;
0001628280-25-020465	20241231	Prepaid Reinsurance Premiums	901700000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20231231	Privately Held Investments Amortized Cost Trading At Fair Value	494900000.0000	USD	0	0001628280-25-020465
0001628280-25-020465	20231231	Privately Held Investments Available For Sale At Fair Value	0.0000	USD	0	0001628280-25-020465	Fair Value By Fair Value Hierarchy Level= Fair Value Inputs Level2; Fair Value By Measurement Frequency= Fair Value Measurements Recurring; Financial Instrument= Trading Assets Excluding Debt And Equity Securities;
0001628280-25-020465	20241231	Privately Held Investments Available For Sale At Fair Value	24200000.0000	USD	0	0001628280-25-020465
0001628280-25-020465	20241231	Proceeds From Issuance Of Preferred Stock And Preference Stock	217000000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20221231	Profit Loss	55000000.0000	USD	4	us-gaap/2024	Equity Components= Accumulated Net Investment Gain Loss Including Portion Attributable To Noncontrolling Interest; Reclassification Out Of Accumulated Other Comprehensive Income= Reclassification Out Of Accumulated Other Comprehensive Income;
0001628280-25-020465	20241231	Profit Loss	486100000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020465	20221231	Purchases Of Privately Held Investments Available For Sale	0.0000	USD	4	0001628280-25-020465
0001628280-25-020465	20241231	Purchases Of Privately Held Investments Available For Sale	10000000.0000	USD	4	0001628280-25-020465
0001628280-25-020465	20221231	Purchases Of Proceeds From Catastrophe Bonds	-500000.0000	USD	4	0001628280-25-020465
0001628280-25-020465	20231231	Reinsurance Payable	1416600000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20231231	Reinsurance Recoverables Allowance	3700000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20231231	Reinsurance Recoverables On Paid And Unpaid Losses	4577800000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20241231	Reinsurance Recoverables On Paid And Unpaid Losses	4172000000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20231231	Retained Earnings Accumulated Deficit	1793500000.0000	USD	0	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020465	20231231	Selling General And Administrative Expense	121300000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020465	20231231	Selling General And Administrative Expense	8100000.0000	USD	4	us-gaap/2024	Equity Components= Accumulated Gain Loss Cash Flow Hedge Including Noncontrolling Interest; Reclassification Out Of Accumulated Other Comprehensive Income= Reclassification Out Of Accumulated Other Comprehensive Income;
0001628280-25-020465	20241231	Selling General And Administrative Expense	533100000.0000	USD	4	us-gaap/2024
0001628280-25-020465	20231231	Shortterminvestmentsavailableforsaleamortizedcost	93600000.0000	USD	0	0001628280-25-020465
0001628280-25-020465	20241231	Shortterminvestmentsavailableforsaleamortizedcost	261900000.0000	USD	0	0001628280-25-020465
0001628280-25-020465	20231231	Short Term Investments Trading Amortized Cost	2100000.0000	USD	0	0001628280-25-020465
0001628280-25-020465	20211231	Stockholders Equity Including Portion Attributable To Noncontrolling Interest	-1600000.0000	USD	0	us-gaap/2024	Equity Components= Accumulated Gain Loss Cash Flow Hedge Including Noncontrolling Interest;
0001628280-25-020465	20211231	Stockholders Equity Including Portion Attributable To Noncontrolling Interest	34600000.0000	USD	0	us-gaap/2024	Equity Components= Accumulated Net Unrealized Investment Gain Loss;
0001628280-25-020465	20211231	Stockholders Equity Including Portion Attributable To Noncontrolling Interest	-156000000.0000	USD	0	us-gaap/2024	Equity Components= Accumulated Translation Adjustment;
0001628280-25-020465	20211231	Stockholders Equity Including Portion Attributable To Noncontrolling Interest	100000.0000	USD	0	us-gaap/2024	Equity Components= Common Stock;
0001628280-25-020465	20231231	Stockholders Equity Including Portion Attributable To Noncontrolling Interest	2908500000.0000	USD	0	us-gaap/2024
0001628280-25-020465	20241231	Stockholders Equity Including Portion Attributable To Noncontrolling Interest	970500000.0000	USD	0	us-gaap/2024	Equity Components= Preferred Stock;
0001628280-25-020463	20241231	Common Stock Value	91000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20231231	Comprehensive Income Net Of Tax	640700000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20231231	Accrued Liabilities Current And Noncurrent	27800000.0000	USD	0	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20241231	Additional Paid In Capital	761700000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20241231	Additional Paid In Capital	761700000.0000	USD	0	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20241231	Assets	3790400000.0000	USD	0	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20211231	Cash And Cash Equivalents At Carrying Value	45000000.0000	USD	0	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20231231	Cash And Cash Equivalents At Carrying Value	43500000.0000	USD	0	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20241231	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations	914200000.0000	USD	0	us-gaap/2024		Cash and cash equivalents includes restricted cash of $181.9 million (2023 $323.2 million, 2022 $232.1 million) which are held in trusts.
0001628280-25-020463	20241231	Catastrophe Bonds Fair Value Disclosure	0.0000	USD	0	0001628280-25-020463	Fair Value By Fair Value Hierarchy Level= Fair Value Inputs Level1; Fair Value By Measurement Frequency= Fair Value Measurements Recurring; Investment Type= Trading Assets Excluding Debt And Equity Securities;
0001628280-25-020463	20241231	Catastrophe Bonds Fair Value Disclosure	1000000.0000	USD	0	0001628280-25-020463	Fair Value By Fair Value Hierarchy Level= Fair Value Inputs Level2; Fair Value By Measurement Frequency= Fair Value Measurements Recurring; Investment Type= Trading Assets Excluding Debt And Equity Securities;
0001628280-25-020463	20241231	Debt Securities Gain Loss	2500000.0000	USD	4	us-gaap/2024	Related Party Transaction= Class A B Notes;
0001628280-25-020463	20221231	Deferred Policy Acquisition Cost Amortization Expense	431800000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20231231	Deferred Policy Acquisition Costs	296200000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20231231	Derivative Assets	31700000.0000	USD	0	us-gaap/2024	Derivative Instrument Risk= Foreign Exchange Contract; Fair Value By Asset Class= Derivative Financial Instruments Assets; Fair Value By Fair Value Hierarchy Level= Fair Value Inputs Level2; Fair Value By Measurement Frequency= Fair Value Measurements Recurring;
0001628280-25-020463	20241231	Derivative Assets	17000000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20241231	Derivative Gain Loss On Derivative Net	-21100000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20241231	Derivative Liabilities	49500000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20241231	Dividends	26822400.0000	USD	4	us-gaap/2024	Class Of Stock= Series D Preferred Stock;
0001628280-25-020463	20221231	Equity Method Investments	6200000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20241231	Finance Lease Right Of Use Asset Amortization	9900000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20231231	Foreign Currency Transaction Gain Loss Before Tax	-36200000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20221231	General And Administrative Expense	142500000.0000	USD	4	us-gaap/2024	Business Segments= Reinsurance; Consolidation Items= Operating Segments;
0001628280-25-020463	20241231	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments	490600000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20231231	Income Taxes Paid Net	60900000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20221231	Income Tax Expense Benefit	0.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20231231	Income Tax Expense Benefit	0.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20221231	Increase Decrease In Deferred Policy Acquisition Costs	28200000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20241231	Increase Decrease In Deferred Policy Acquisition Costs	25900000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20231231	Increase Decrease In Derivative Instruments	15400000.0000	USD	4	0001628280-25-020463
0001628280-25-020463	20241231	Increase Decrease In Liability For Claims And Claims Adjustment Expense Reserve	312000000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20241231	Increase Decrease In Other Operating Assets	3800000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20241231	Increase Decrease In Premiums Receivable	181700000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20221231	Increase Decrease In Reinsurance Payables	1404400000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20231231	Investments Excluding Derivative Assets	6412400000.0000	USD	0	0001628280-25-020463
0001628280-25-020463	20241231	Liabilities	418500000.0000	USD	0	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20211231	Liability For Claims And Claims Adjustment Expense	7611800000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20231231	Liability For Claims And Claims Adjustment Expense	1859700000.0000	USD	0	us-gaap/2024	Business Segments= Insurance;
0001628280-25-020463	20231231	Liability For Claims And Claims Adjustment Expense	1373100000.0000	USD	0	us-gaap/2024	Business Segments= Reinsurance;
0001628280-25-020463	20241231	Liability For Claims And Claims Adjustment Expense	2259100000.0000	USD	0	us-gaap/2024	Business Segments= Insurance;
0001628280-25-020463	20241231	Liability For Claims And Claims Adjustment Expense	1691500000.0000	USD	0	us-gaap/2024	Business Segments= Reinsurance;
0001628280-25-020463	20221231	Net Cash Provided By Used In Financing Activities	-84600000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20221231	Net Cash Provided By Used In Financing Activities	-84600000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20241231	Net Cash Provided By Used In Investing Activities	41000000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20221231	Net Cash Provided By Used In Operating Activities	81200000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20221231	Net Changein Receivablefor Securities Soldor Payablefor Securities Purchased	-31800000.0000	USD	4	0001628280-25-020463
0001628280-25-020463	20231231	Net Income Loss	534700000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20221231	Net Investment Income	0.0000	USD	4	us-gaap/2024	Related Party Transactions By Related Party= Middle Market Term Loans;
0001628280-25-020463	20231231	Net Investment Income	17400000.0000	USD	4	us-gaap/2024	Related Party Transactions By Related Party= C L Os;
0001628280-25-020463	20231231	Net Investment Income	5800000.0000	USD	4	us-gaap/2024	Related Party Transactions By Related Party= Middle Market Term Loans;
0001628280-25-020463	20231231	Operating Lease Liability	86100000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20241231	Operating Lease Payments	500000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20231231	Other Comprehensive Income Loss Before Tax	126600000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20231231	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax Parent	-14000000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20241231	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax Parent	-5100000.0000	USD	4	us-gaap/2024	Equity Components= Accumulated Translation Adjustment;
0001628280-25-020463	20241231	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Before Tax	-14100000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20221231	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax	-23900000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20241231	Other Income	4300000.0000	USD	4	us-gaap/2024	Consolidated Entities= Parent Company;
0001628280-25-020463	20241231	Other Investments	88900000.0000	USD	0	us-gaap/2024	Fair Value By Measurement Frequency= Fair Value Measurements Recurring; Investment Type= Asset Backed Securities; Related Party Transactions By Related Party= Apollo Originating Partnership;
0001628280-25-020463	20231231	Paymentsfor Proceedsfrom Investing Activities Netof Cash	-4900000.0000	USD	4	0001628280-25-020463
0001628280-25-020463	20231231	Payments Of Dividends Common Stock	40300000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20241231	Payments Of Dividends Preferred Stock And Preference Stock	54900000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20221231	Payments To Acquire Available For Sale Securities Debt	1613900000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20221231	Payments To Acquire Equity Method Investments	2000000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20221231	Payments To Acquire Privately Held Investments Trading	377900000.0000	USD	4	0001628280-25-020463
0001628280-25-020463	20231231	Payments To Acquire Short Term Investments	15100000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20221231	Policyholder Benefits And Claims Incurred Net	909700000.0000	USD	4	us-gaap/2024	Business Segments= Insurance; Consolidation Items= Operating Segments;
0001628280-25-020463	20241231	Policyholder Benefits And Claims Incurred Net	1717800000.0000	USD	4	us-gaap/2024
0001628280-25-020463	20231231	Preferred Stock Dividend Rate Percentage	0.0563	pure	4	us-gaap/2024	Class Of Stock= Series E Preferred Stock;
0001628280-25-020463	20241231	Preferred Stock Dividend Rate Percentage	0.0595	pure	4	us-gaap/2024	Class Of Stock= Series D Preferred Stock;
0001628280-25-020463	20241231	Preferred Stock Dividend Rate Percentage	0.0700	pure	4	us-gaap/2024	Class Of Stock= Series G Preferred Stock;
0001628280-25-020463	20250228	Preferred Stock Dividend Rate Percentage	0.0563	pure	0	us-gaap/2024	Class Of Stock= Series E Preferred Stock; Subsequent Event Type= Subsequent Event;
0001628280-25-020463	20190731	Preferred Stock Liquidation Preference Value	250000000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20241231	Preferred Stock Liquidation Preference Value	275000000.0000	USD	0	us-gaap/2024	Class Of Stock= Series D Preferred Stock; Subsequent Event Type= Subsequent Event;
0001628280-25-020463	20160930	Preferred Stock Shares Issued	10000000.0000	shares	0	us-gaap/2024	Class Of Stock= Series E Preferred Stock;
0001628280-25-020463	20221231	Premiums Earned Net	1436900000.0000	USD	4	us-gaap/2024	Business Segments= Insurance; Consolidation Items= Operating Segments;
0001628280-25-020463	20231231	Prepaid Reinsurance Premiums	733500000.0000	USD	0	us-gaap/2024
0001628280-25-020463	20241231	Privatelyheld Investments	66600000.0000	USD	0	0001628280-25-020463	Fair Value By Measurement Frequency= Fair Value Measurements Recurring; Related Party Transactions By Related Party= Apollo S P V;
0001628280-25-020463	20231231	Privately Held Investments Amortized Cost Available For Sale	14700000.0000	USD	0	0001628280-25-020463
0001628280-25-020463	20231231	Privately Held Investments Available For Sale At Fair Value	14900000.0000	USD	0	0001628280-25-020463
0001628280-25-020463	20231231	Privately Held Investments Available For Sale At Fair Value	0.0000	USD	0	0001628280-25-020463	Fair Value By Fair Value Hierarchy Level= Fair Value Inputs Level2; Fair Value By Measurement Frequency= Fair Value Measurements Recurring; Financial Instrument= Trading Assets Excluding Debt And Equity Securities;
0001628280-25-020463	20241231	Privately Held Investments Available For Sale At Fair Value	0.0000	USD	0	0001628280-25-020463	Fair Value By Fair Value Hierarchy Level= Fair Value Inputs Level2; Fair Value By Measurement Frequency= Fair Value Measurements Recurring; Investment Type= Privately Held Investments Available For Sale;
0001628280-25-020463	20221231	Proceeds From Issuance Of Preferred Stock And Preference Stock	0.0000	USD	4	us-gaap/2024	Equity Components= Parent;

Description

Field Name	Field Description
adsh	Accession Number. The 20-character string formed from the 18-digit number assigned by the SEC to each EDGAR submission.
tag	The unique identifier (name) for a tag in a specific taxonomy release.
version	For a standard tag, an identifier for the taxonomy; otherwise the accession number where the tag was defined.
ddate	The end date for the data value, rounded to the nearest month end.
qtrs	The count of the number of quarters represented by the data value, rounded to the nearest whole number. “0” indicates it is a point-in-time value.
uom	The unit of measure for the value.
segments	Tags used to represent axis and member reporting.
coreg	If specified, indicates a specific co-registrant, the parent company, or other entity (e.g., guarantor). NULL indicates the consolidated entity.
value	The value. This is not scaled, it is as found in the Interactive Data file, but is limited to four digits to the right of the decimal point.
footnote	The text of any superscripted footnotes on the value, as shown on the statement page, truncated to 512 characters, or if there is no footnote, then this field will be blank.

Tags

tag	version	custom	datatype	iord	crdr	tlabel	doc
Payments For Proceeds From Productive Assets	us-gaap/2024	0	monetary	D	C	Payments for (Proceeds from) Productive Assets	The net cash outflow or inflow from purchases, sales and disposals of property, plant and equipment and other productive assets, including intangibles.
Payments To Acquire Equity Method Investments	us-gaap/2024	0	monetary	D	C	Payments to Acquire Equity Method Investments	The cash outflow associated with the purchase of or advances to an equity method investments, which are investments in joint ventures and entities in which the entity has an equity ownership interest normally of 20 to 50 percent and exercises significant influence.
Aggregate Liquidation Preference Shares	0001628280-25-020463	1	monetary	D	C	Aggregate Liquidation Preference Shares	Aggregate liquidation preferences
Other Comprehensive Income Loss Tax Portion Attributable To Parent1	us-gaap/2024	0	monetary	D	D	Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	Amount of tax expense (benefit) allocated to other comprehensive income (loss) attributable to parent entity.
Stockholders Equity Including Portion Attributable To Noncontrolling Interest	us-gaap/2024	0	monetary	I	C	Equity, Including Portion Attributable to Noncontrolling Interest	Amount of equity (deficit) attributable to parent and noncontrolling interest. Excludes temporary equity.
Deferred Income Tax Assets Net	us-gaap/2024	0	monetary	I	D	Deferred Income Tax Assets, Net	Amount, after allocation of valuation allowances and deferred tax liability, of deferred tax asset attributable to deductible differences and carryforwards, with jurisdictional netting.
Payments To Acquire Privately Held Investments Trading	0001628280-25-020465	1	monetary	D	C	Payments to Acquire Privately-held Investments, Trading	Payments to Acquire Privately-held Investments, Trading
Proceedsfrom Saleof Privatelyheld Investments	0001628280-25-020465	1	monetary	D	D	Proceeds from Sale of Privately-held Investments	Proceeds from Sale of Privately-held Investments
Gains Losses On Investment And Foreign Exchange	0001628280-25-020463	1	monetary	D	C	Gains (Losses) On Investment And Foreign Exchange	Gains (losses) on investment and foreign exchange.
Comprehensive Income Net Of Tax	us-gaap/2024	0	monetary	D	C	Comprehensive Income (Loss), Net of Tax, Attributable to Parent	Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.
Deferred Policy Acquisition Costs	us-gaap/2024	0	monetary	I	D	Deferred Policy Acquisition Cost	Amount of deferred policy acquisition cost capitalized on contract remaining in force.
Gain Loss On Investments	us-gaap/2024	0	monetary	D	C	Gain (Loss) on Investments	Amount of realized and unrealized gain (loss) on investment.
Increase Decrease In Premiums Receivable	us-gaap/2024	0	monetary	D	C	Increase (Decrease) in Premiums Receivable	The change in the premium receivable balance on the balance sheet.
Increase Decrease In Prepaid Reinsurance Premiums	us-gaap/2024	0	monetary	D	C	Increase (Decrease) in Prepaid Reinsurance Premiums	The change in prepaid reinsurance premiums recorded on the balance sheet, which is needed to adjust net income to arrive at net cash flows provided by or used in operations.
Liabilities	us-gaap/2024	0	monetary	I	C	Liabilities	Amount of liability recognized for present obligation requiring transfer or otherwise providing economic benefit to others.
Liabilities And Stockholders Equity	us-gaap/2024	0	monetary	I	C	Liabilities and Equity	Amount of liabilities and equity items, including the portion of equity attributable to noncontrolling interests, if any.
Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Tax	us-gaap/2024	0	monetary	D	D	Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, Tax	Amount, after reclassification, of tax expense (benefit) for gain (loss) from derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness.
Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Before Tax	us-gaap/2024	0	monetary	D	C	Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, before Tax	Amount before tax, after reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature.
Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax	us-gaap/2024	0	monetary	D	C	OCI, Debt Securities, Available-for-Sale, Unrealized Holding Gain (Loss), before Adjustment and Tax	Amount, before tax and adjustment, of unrealized holding gain (loss) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). Excludes unrealized gain (loss) on investment in debt security measured at amortized cost (held-to-maturity) from transfer to available-for-sale.
Other Income	us-gaap/2024	0	monetary	D	C	Other Income	Amount of revenue and income classified as other.
Preferred Stock Liquidation Preference Value	us-gaap/2024	0	monetary	I	C	Preferred Stock, Liquidation Preference, Value	Value of the difference between preference in liquidation and the par or stated values of the preferred shares.
Reinsurance Recoverables Allowance	us-gaap/2024	0	monetary	I	C	Reinsurance Recoverable, Allowance for Credit Loss	Amount of allowance for credit loss on reinsurance recoverable.
Retained Earnings Accumulated Deficit	us-gaap/2024	0	monetary	I	C	Retained Earnings (Accumulated Deficit)	Amount of accumulated undistributed earnings (deficit).
Accrued Liabilities Current And Noncurrent	us-gaap/2024	0	monetary	I	C	Accrued Liabilities	Carrying value as of the balance sheet date of obligations incurred and payable, pertaining to costs that are statutory in nature, are incurred on contractual obligations, or accumulate over time and for which invoices have not yet been received or will not be rendered. Examples include taxes, interest, rent and utilities.
Catastrophe Bonds Fair Value Disclosure	0001628280-25-020465	1	monetary	I	D	Catastrophe Bonds, Fair Value Disclosure	Catastrophe Bonds, Fair Value Disclosure
Shortterminvestmentsavailableforsaleamortizedcost	0001628280-25-020465	1	monetary	I	D	Short term investments available for sale, amortized cost	Short term investments available for sale, amortized cost
Catastrophe Bonds Fair Value Disclosure	0001628280-25-020463	1	monetary	I	D	Catastrophe Bonds, Fair Value Disclosure	Catastrophe Bonds, Fair Value Disclosure
Fixed Income Debt Securities Available For Sale Allowance For Credit Loss	0001628280-25-020463	1	monetary	I	C	Fixed income Debt Securities, Available-for-Sale, Allowance for Credit Loss	Fixed income Debt Securities, Available-for-Sale, Allowance for Credit Loss
Fixed Income Debt Securities Trading	0001628280-25-020463	1	monetary	I	D	Fixed Income Debt Securities, Trading	Fixed Income Debt Securities, Trading
Short Term Investments Trading At Fair Value	0001628280-25-020463	1	monetary	I	D	Short-term investments, trading at fair value	Short-term investments, trading at fair value
Unrealized Gainloss On Real Estate Fund In Net Investment Income	0001628280-25-020463	1	monetary	D	C	Unrealized (gain)/loss on real estate fund in net investment income	Unrealized (gain)/loss on real estate fund in net investment income
Dividends	us-gaap/2024	0	monetary	D	D	Dividends	Amount of paid and unpaid cash, stock, and paid-in-kind (PIK) dividends declared, for example, but not limited to, common and preferred stock.
Income Tax Expense Benefit	us-gaap/2024	0	monetary	D	D	Income Tax Expense (Benefit)	Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.
Intangible Assets Net Including Goodwill	us-gaap/2024	0	monetary	I	D	Intangible Assets, Net (Including Goodwill)	Amount, after impairment and amortization, of goodwill, indefinite-lived, and finite-lived intangible assets.
Interest Paid	us-gaap/2024	0	monetary	D	C	Interest Paid, Including Capitalized Interest, Operating and Investing Activities	Amount of cash paid for interest, including, but not limited to, capitalized interest and payment to settle zero-coupon bond attributable to accreted interest of debt discount and debt instrument with insignificant coupon interest rate in relation to effective interest rate of borrowing attributable to accreted interest of debt discount; classified as operating and investing activities.
Net Income Loss	us-gaap/2024	0	monetary	D	C	Net Income (Loss) Attributable to Parent	The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.
Net Income Loss From Continuing Operations Available To Common Shareholders Basic	us-gaap/2024	0	monetary	D	C	Net Income (Loss) from Continuing Operations Available to Common Shareholders, Basic	Amount, after deduction of tax, noncontrolling interests, dividends on preferred stock and participating securities; of income (loss) from continuing operations available to common shareholders.
Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax Parent	us-gaap/2024	0	monetary	D	C	Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax, Parent	Amount, after tax and reclassification, of gain (loss) from derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness, attributable to parent.
Payments To Acquire Trading Securities Heldforinvestment	us-gaap/2024	0	monetary	D	C	Payment for Acquisition, Trading Security, Held-for-Investment	The cash outflow to acquire securities classified as trading securities and held for investment purposes. Excludes payments for trading securities purchased and held principally for the purpose of selling them in the near term (thus held for only a short period of time).
Repayments Of Short Term Debt	us-gaap/2024	0	monetary	D	C	Repayments of Short-Term Debt	The cash outflow for a borrowing having initial term of repayment within one year or the normal operating cycle, if longer.
Additional Paid In Capital	us-gaap/2024	0	monetary	I	C	Additional Paid in Capital	Amount of excess of issue price over par or stated value of stock and from other transaction involving stock or stockholder. Includes, but is not limited to, additional paid-in capital (APIC) for common and preferred stock.
Paymentsfor Availableforsale Securities Shortterm	0001628280-25-020465	1	monetary	D	C	Payments for Available-for-sale Securities, Short-term	Payments for Available-for-sale Securities, Short-term
Privately Held Investments Amortized Cost Trading At Fair Value	0001628280-25-020465	1	monetary	I	D	Privately-held investments, amortized cost, trading at fair value	Privately-held investments, amortized cost, trading at fair value
Privately Held Investments Available For Sale At Fair Value	0001628280-25-020465	1	monetary	I	D	Privately-held Investments, available for sale, at fair value	Privately-held Investments, available for sale, at fair value
Catastrophe Bond	0001628280-25-020463	1	monetary	I	D	Catastrophe Bond	Catastrophe Bond
Fixed Income Debt Securities Available For Sale	0001628280-25-020463	1	monetary	I	D	Fixed Income Debt Securities, Available-for-Sale	Fixed Income Debt Securities, Available-for-Sale
Payments To Acquire Privately Held Investments Trading	0001628280-25-020463	1	monetary	D	C	Payments to Acquire Privately-held Investments, Trading	Payments to Acquire Privately-held Investments, Trading
Privately Held Investments Available For Sale At Fair Value	0001628280-25-020463	1	monetary	I	D	Privately-held Investments, available for sale, at fair value	Privately-held Investments, available for sale, at fair value
Proceeds From Term Loan Facility	0001628280-25-020463	1	monetary	D	D	Proceeds from term loan facility	Proceeds from term loan facility
Purchases Of Privately Held Investments Available For Sale	0001628280-25-020463	1	monetary	D	C	(Purchases of) privately-held investments, available for sale	(Purchases of) privately-held investments, available for sale
Accumulated Other Comprehensive Income Loss Net Of Tax	us-gaap/2024	0	monetary	I	C	Accumulated Other Comprehensive Income (Loss), Net of Tax	Amount, after tax, of accumulated increase (decrease) in equity from transaction and other event and circumstance from nonowner source.
Assets	us-gaap/2024	0	monetary	I	D	Assets	Amount of asset recognized for present right to economic benefit.
Depreciation Amortization And Accretion Net	us-gaap/2024	0	monetary	D	D	Depreciation, Amortization and Accretion, Net	The aggregate net amount of depreciation, amortization, and accretion recognized during an accounting period. As a noncash item, the net amount is added back to net income when calculating cash provided by or used in operations using the indirect method.
Earnings Per Share Diluted	us-gaap/2024	0	perShare	D		Earnings Per Share, Diluted	The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.
Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents	us-gaap/2024	0	monetary	D	D	Effect of Exchange Rate on Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Continuing Operations	Amount of increase (decrease) from effect of exchange rate changes on cash and cash equivalents, and cash and cash equivalents restricted to withdrawal or usage; held in foreign currencies. Excludes amounts for disposal group and discontinued operations. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. Cash equivalents include, but are not limited to, short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.
Income Tax Receivable	us-gaap/2024	0	monetary	I	D	Income Taxes Receivable	Carrying amount as of the balance sheet date of income taxes previously overpaid to tax authorities (such as U.S. Federal, state and local tax authorities) representing refunds of overpayments or recoveries based on agreed-upon resolutions of disputes. Also called income tax refund receivable.
Operating Lease Right Of Use Asset	us-gaap/2024	0	monetary	I	D	Operating Lease, Right-of-Use Asset	Amount of lessee's right to use underlying asset under operating lease.
Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Before Tax	us-gaap/2024	0	monetary	D	C	Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, before Tax	Amount, before tax and after reclassification, of gain (loss) from derivative instrument designated and qualifying cash flow hedge included in assessment of hedge effectiveness.
Payments For Proceeds From Other Investing Activities	us-gaap/2024	0	monetary	D	C	Payments for (Proceeds from) Other Investing Activities	Amount of cash (inflow) outflow from investing activities classified as other.
Payments For Repurchase Of Preferred Stock And Preference Stock	us-gaap/2024	0	monetary	D	C	Payments for Repurchase of Preferred Stock and Preference Stock	The cash outflow to reacquire preferred stock during the period.
Policyholder Benefits And Claims Incurred Net	us-gaap/2024	0	monetary	D	D	Policyholder Benefits and Claims Incurred, Net	Amount, after effects of policies assumed or ceded, of expense related to the provision for policy benefits and costs incurred.
Premiums Receivable At Carrying Value	us-gaap/2024	0	monetary	I	D	Premiums Receivable, Net	The carrying amount as of the balance sheet date due the entity from (a) agents and insureds, (b) uncollected premiums and (c) others, net of the allowance for doubtful accounts.
Proceeds From Issuance Of Preferred Stock And Preference Stock	us-gaap/2024	0	monetary	D	D	Proceeds from Issuance of Preferred Stock and Preference Stock	Proceeds from issuance of capital stock which provides for a specific dividend that is paid to the shareholders before any dividends to common stockholders and which takes precedence over common stockholders in the event of liquidation.
Unearned Premiums	us-gaap/2024	0	monetary	I	C	Unearned Premiums	Carrying amount of premiums written on insurance contracts that have not been earned as of the balance sheet date.
Cash And Cash Equivalents Includes Restricted Cash	0001628280-25-020463	1	monetary	I	D	Cash and cash equivalents includes restricted cash	Cash and cash equivalents includes restricted cash
Proceedsfrom Availableforsale Securities Shortterm	0001628280-25-020463	1	monetary	D	D	Proceeds from Available-for-sale Securities, Short-term	Proceeds from Available-for-sale Securities, Short-term
Increase Decrease In Accrued Income Taxes Payable	us-gaap/2024	0	monetary	D	D	Increase (Decrease) in Income Taxes Payable	The increase (decrease) during the period in the amount due for taxes based on the reporting entity's earnings or attributable to the entity's income earning process (business presence) within a given jurisdiction.
Derivative Liabilities	us-gaap/2024	0	monetary	I	C	Derivative Liability	Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset.
Operating Lease Liability	us-gaap/2024	0	monetary	I	C	Operating Lease, Liability	Present value of lessee's discounted obligation for lease payments from operating lease.
Increase Decrease In Liability For Claims And Claims Adjustment Expense Reserve	us-gaap/2024	0	monetary	D	D	Increase (Decrease) in Liability for Claims and Claims Adjustment Expense Reserve	Amount of increase (decrease) in liability to reflect the estimated ultimate cost of settling claims relating to insured events that have occurred on or before the balance sheet date, whether or not reported to the insurer at that date.
Increase Decrease In Other Operating Assets	us-gaap/2024	0	monetary	D	C	Increase (Decrease) in Other Operating Assets	Amount of increase (decrease) in operating assets classified as other.
Increase Decrease In Reinsurance Payables	us-gaap/2024	0	monetary	D	D	Increase (Decrease) in Reinsurance Payables	The increase (decrease) during the reporting period in the amount due to other insurance companies when the reporting entity has assumed a portion of the cedant's insurance risk which has resulted in insurance losses.
Operating Lease Payments	us-gaap/2024	0	monetary	D	C	Operating Lease, Payments	Amount of cash outflow from operating lease, excluding payments to bring another asset to condition and location necessary for its intended use.
Other Expenses	us-gaap/2024	0	monetary	D	D	Other Expenses	Amount of expense classified as other.
Payments To Acquire Available For Sale Securities Debt	us-gaap/2024	0	monetary	D	C	Payments to Acquire Debt Securities, Available-for-Sale	Amount of cash outflow to acquire investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).
Selling General And Administrative Expense	us-gaap/2024	0	monetary	D	D	Selling, General and Administrative Expense	The aggregate total costs related to selling a firm's product and services, as well as all other general and administrative expenses. Direct selling expenses (for example, credit, warranty, and advertising) are expenses that can be directly linked to the sale of specific products. Indirect selling expenses are expenses that cannot be directly linked to the sale of specific products, for example telephone expenses, Internet, and postal charges. General and administrative expenses include salaries of non-sales personnel, rent, utilities, communication, etc.
Preferred Stock Shares Issued	us-gaap/2024	0	shares	I		Preferred Stock, Shares Issued	Number of shares issued for nonredeemable preferred shares and preferred shares redeemable solely at option of issuer. Includes, but is not limited to, preferred shares issued, repurchased, and held as treasury shares. Excludes preferred shares classified as debt.
Cash And Cash Equivalents At Carrying Value	us-gaap/2024	0	monetary	I	D	Cash and Cash Equivalents, at Carrying Value	Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.
Aggregate Liquidation Preference Shares	0001628280-25-020465	1	monetary	D	C	Aggregate Liquidation Preference Shares	Aggregate liquidation preferences
Fixed Income Debt Securities Available For Sale Including Related Party Investments	0001628280-25-020465	1	monetary	I	D	Fixed Income Debt Securities, Available for Sale, Including Related Party Investments	Fixed Income Debt Securities, Available for Sale, Including Related Party Investments
Interest On Operating Lease Liabilities	0001628280-25-020465	1	monetary	D	D	Interest on operating lease liabilities	Interest on operating lease liabilities
Investments Excluding Derivative Assets	0001628280-25-020465	1	monetary	I	D	Investments, Excluding Derivative Assets	Investments, Excluding Derivative Assets
Privately Held Investments Amortized Cost Available For Sale	0001628280-25-020465	1	monetary	I	D	Privately-held investments, amortized cost, available for sale	Privately-held investments, amortized cost, available for sale
Purchases Of Proceeds From Catastrophe Bonds	0001628280-25-020465	1	monetary	D	C	Purchases Of (Proceeds From) Catastrophe Bonds	Purchases Of (Proceeds From) Catastrophe Bonds
Unrealized Gainloss On Real Estate Fund In Net Investment Income	0001628280-25-020465	1	monetary	D	C	Unrealized (gain)/loss on real estate fund in net investment income	Unrealized (gain)/loss on real estate fund in net investment income
Expense	0001628280-25-020463	1	monetary	D	D	Expense	Expense.
Paymentsfor Proceedsfrom Investing Activities Netof Cash	0001628280-25-020463	1	monetary	D	C	Payments for (Proceeds from) Investing Activities, Net of Cash	Payments for (Proceeds from) Investing Activities, Net of Cash
Privately Held Investments Amortized Cost Available For Sale	0001628280-25-020463	1	monetary	I	D	Privately-held investments, amortized cost, available for sale	Privately-held investments, amortized cost, available for sale
Debt Securities Gain Loss	us-gaap/2024	0	monetary	D	C	Debt Securities, Gain (Loss)	Amount of unrealized and realized gain (loss) on investment in debt security measured at amortized cost (held-to-maturity), investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale) and investment in debt security measured at fair value with change in fair value recognized in net income (trading).
Equity Method Investments	us-gaap/2024	0	monetary	I	D	Equity Method Investments	This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized.
Finance Lease Right Of Use Asset Amortization	us-gaap/2024	0	monetary	D	D	Finance Lease, Right-of-Use Asset, Amortization	Amount of amortization expense attributable to right-of-use asset from finance lease.
Income Taxes Paid Net	us-gaap/2024	0	monetary	D	C	Income Taxes Paid, Net	Amount, after refund, of cash paid to foreign, federal, state, and local jurisdictions as income tax.
Foreign Currency Transaction Gain Loss Before Tax	us-gaap/2024	0	monetary	D	C	Gain (Loss), Foreign Currency Transaction, before Tax	Amount, before tax, of realized and unrealized gain (loss) from foreign currency transaction.
Other Comprehensive Income Loss Net Of Tax	us-gaap/2024	0	monetary	D	C	Other Comprehensive Income (Loss), Net of Tax	Amount after tax and reclassification adjustments of other comprehensive income (loss).
Interest Expense Debt	us-gaap/2024	0	monetary	D	D	Interest Expense, Debt	Amount of the cost of borrowed funds accounted for as interest expense for debt.
Proceeds From Sale Of Short Term Investments	us-gaap/2024	0	monetary	D	D	Proceeds from Sale of Short-Term Investments	The cash inflow from sales of all investments, including securities and other assets, having ready marketability and intended by management to be liquidated, if necessary, within the current operating cycle. Includes cash flows from securities classified as trading securities that were acquired for reasons other than sale in the short-term.
Preferred Stock Dividend Rate Percentage	us-gaap/2024	0	percent	D		Preferred Stock, Dividend Rate, Percentage	The percentage rate used to calculate dividend payments on preferred stock.
Preferred Stock Value	us-gaap/2024	0	monetary	I	C	Preferred Stock, Value, Issued	Aggregate par or stated value of issued nonredeemable preferred stock (or preferred stock redeemable solely at the option of the issuer). This item includes treasury stock repurchased by the entity. Note: elements for number of nonredeemable preferred shares, par value and other disclosure concepts are in another section within stockholders' equity.
Premiums Earned Net	us-gaap/2024	0	monetary	D	C	Premiums Earned, Net	Amount, after premiums ceded to other entities and premiums assumed by the entity, of premiums earned.
Profit Loss	us-gaap/2024	0	monetary	D	C	Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest.
Fixed Income Debt Securities Trading Amortized Cost	0001628280-25-020465	1	monetary	I	D	Fixed Income Debt Securities, Trading, Amortized Cost	Fixed Income Debt Securities, Trading, Amortized Cost
Privatelyheld Investments	0001628280-25-020465	1	monetary	I	D	Privately-held Investments	Privately-held Investments
Proceeds From Term Loan Facility	0001628280-25-020465	1	monetary	D	D	Proceeds from term loan facility	Proceeds from term loan facility
Short Term Investments Trading At Fair Value	0001628280-25-020465	1	monetary	I	D	Short-term investments, trading at fair value	Short-term investments, trading at fair value
Fixed Income Debt Securities Trading Amortized Cost	0001628280-25-020463	1	monetary	I	D	Fixed Income Debt Securities, Trading, Amortized Cost	Fixed Income Debt Securities, Trading, Amortized Cost
Increase Decrease In Unpaid Losses Recoverable From Reinsurers	0001628280-25-020463	1	monetary	D	D	Increase (Decrease) in Unpaid Losses Recoverable from Reinsurers	Increase (Decrease) in Unpaid Losses Recoverable from Reinsurers
Investments Excluding Derivative Assets	0001628280-25-020463	1	monetary	I	D	Investments, Excluding Derivative Assets	Investments, Excluding Derivative Assets
Paymentsfor Availableforsale Securities Shortterm	0001628280-25-020463	1	monetary	D	C	Payments for Available-for-sale Securities, Short-term	Payments for Available-for-sale Securities, Short-term
Purchases Of Proceeds From Catastrophe Bonds	0001628280-25-020463	1	monetary	D	C	Purchases Of (Proceeds From) Catastrophe Bonds	Purchases Of (Proceeds From) Catastrophe Bonds
Net Cash Provided By Used In Operating Activities	us-gaap/2024	0	monetary	D		Net Cash Provided by (Used in) Operating Activities	Amount of cash inflow (outflow) from operating activities, including discontinued operations. Operating activity cash flows include transactions, adjustments, and changes in value not defined as investing or financing activities.
Accrued Income Taxes Current	us-gaap/2024	0	monetary	I	C	Accrued Income Taxes, Current	Carrying amount as of the balance sheet date of the unpaid sum of the known and estimated amounts payable to satisfy all currently due domestic and foreign income tax obligations.
Deferred Policy Acquisition Cost Amortization Expense	us-gaap/2024	0	monetary	D	D	Deferred Policy Acquisition Costs, Amortization Expense	Amount of amortization expense (reversal of expense) for deferred policy acquisition costs.
Increase Decrease In Deferred Income Taxes	us-gaap/2024	0	monetary	D	C	Increase (Decrease) in Deferred Income Taxes	The increase (decrease) during the reporting period in the account that represents the temporary difference that results from Income or Loss that is recognized for accounting purposes but not for tax purposes and vice versa.
Liability For Claims And Claims Adjustment Expense	us-gaap/2024	0	monetary	I	C	Liability for Claims and Claims Adjustment Expense	The amount needed to reflect the estimated ultimate cost of settling claims relating to insured events that have occurred on or before the balance sheet date, whether or not reported to the insurer at that date.
Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax	us-gaap/2024	0	monetary	D	C	OCI, Debt Securities, Available-for-Sale, Gain (Loss), after Adjustment and Tax	Amount, after tax and adjustment, of unrealized gain (loss) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale) and unrealized gain (loss) on investment in debt security measured at amortized cost (held-to-maturity) from transfer to available-for-sale.
Common Stock Value	us-gaap/2024	0	monetary	I	C	Common Stock, Value, Issued	Aggregate par or stated value of issued nonredeemable common stock (or common stock redeemable solely at the option of the issuer). This item includes treasury stock repurchased by the entity. Note: elements for number of nonredeemable common shares, par value and other disclosure concepts are in another section within stockholders' equity.
Short Term Borrowings	us-gaap/2024	0	monetary	I	C	Short-Term Debt	Reflects the total carrying amount as of the balance sheet date of debt having initial terms less than one year or the normal operating cycle, if longer.
Fixed Income Debt Securities Available For Sale Allowance For Credit Loss	0001628280-25-020465	1	monetary	I	C	Fixed income Debt Securities, Available-for-Sale, Allowance for Credit Loss	Fixed income Debt Securities, Available-for-Sale, Allowance for Credit Loss
Preferred Stock Issuance Cost	0001628280-25-020465	1	monetary	D	D	Preferred Stock Issuance Cost	Preferred stock issuance cost
Fixed Income Debt Securities Available For Sale Amortized Cost	0001628280-25-020463	1	monetary	I	D	Fixed Income Debt Securities, Available-for-Sale, Amortized Cost	Fixed Income Debt Securities, Available-for-Sale, Amortized Cost
Insurance Reserves	0001628280-25-020463	1	monetary	I	C	Insurance Reserves	Insurance reserves.
Net Changein Receivablefor Securities Soldor Payablefor Securities Purchased	0001628280-25-020463	1	monetary	D	D	Net Change in Receivable for Securities Sold or Payable for Securities Purchased	Net Change in Receivable for Securities Sold or Payable for Securities Purchased
Revenues	us-gaap/2024	0	monetary	D	C	Revenues	Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).
General And Administrative Expense	us-gaap/2024	0	monetary	D	D	General and Administrative Expense	The aggregate total of expenses of managing and administering the affairs of an entity, including affiliates of the reporting entity, which are not directly or indirectly associated with the manufacture, sale or creation of a product or product line.
Net Cash Provided By Used In Financing Activities	us-gaap/2024	0	monetary	D	D	Net Cash Provided by (Used in) Financing Activities	Amount of cash inflow (outflow) from financing activities, including discontinued operations. Financing activity cash flows include obtaining resources from owners and providing them with a return on, and a return of, their investment; borrowing money and repaying amounts borrowed, or settling the obligation; and obtaining and paying for other resources obtained from creditors on long-term credit.
Redeemable Preferred Stock Dividends	us-gaap/2024	0	monetary	D	D	Redeemable Preferred Stock Dividends	Dividends paid to preferred stock holders that is redeemable solely at the option of the issuer.
Catastrophe Bond	0001628280-25-020465	1	monetary	I	D	Catastrophe Bond	Catastrophe Bond
Insurance Reserves	0001628280-25-020465	1	monetary	I	C	Insurance Reserves	Insurance reserves
Proceedsfrom Availableforsale Securities Shortterm	0001628280-25-020465	1	monetary	D	D	Proceeds from Available-for-sale Securities, Short-term	Proceeds from Available-for-sale Securities, Short-term
Preferred Stock Issuance Cost	0001628280-25-020463	1	monetary	D	D	Preferred Stock Issuance Cost	Preferred stock issuance cost.
Shortterminvestmentsavailableforsaleamortizedcost	0001628280-25-020463	1	monetary	I	D	Short term investments available for sale, amortized cost	Short term investments available for sale, amortized cost
Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect	us-gaap/2024	0	monetary	D	D	Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect	Amount of increase (decrease) in cash, cash equivalents, and cash and cash equivalents restricted to withdrawal or usage; including effect from exchange rate change. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. Cash equivalents include, but are not limited to, short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.
Commitments And Contingencies	us-gaap/2024	0	monetary	I	C	Commitments and Contingencies	Represents the caption on the face of the balance sheet to indicate that the entity has entered into (1) purchase or supply arrangements that will require expending a portion of its resources to meet the terms thereof, and (2) is exposed to potential losses or, less frequently, gains, arising from (a) possible claims against a company's resources due to future performance under contract terms, and (b) possible losses or likely gains from uncertainties that will ultimately be resolved when one or more future events that are deemed likely to occur do occur or fail to occur.
Deferred Income Tax Liabilities Net	us-gaap/2024	0	monetary	I	C	Deferred Income Tax Liabilities, Net	Amount, after deferred tax asset, of deferred tax liability attributable to taxable differences with jurisdictional netting.
Premiums Receivable Allowance For Doubtful Accounts	us-gaap/2024	0	monetary	I	C	Premium Receivable, Allowance for Credit Loss	The carrying value as of the balance sheet date of the estimated valuation allowance to reduce gross premiums receivable to net realizable value.
Prepaid Reinsurance Premiums	us-gaap/2024	0	monetary	I	D	Prepaid Reinsurance Premiums	The unexpired portion of premiums ceded on policies in force as of the balance sheet date.
Proceeds From Sale Of Available For Sale Securities Debt	us-gaap/2024	0	monetary	D	D	Proceeds from Sale of Debt Securities, Available-for-Sale	Amount of cash inflow from sale of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).
Reclassification From Accumulated Other Comprehensive Income Current Period Before Tax	us-gaap/2024	0	monetary	D	D	Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	Amount before tax of reclassification adjustments of other comprehensive income (loss).
Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities	us-gaap/2024	0	monetary	D	D	Proceeds from Maturities, Prepayments and Calls of Debt Securities, Available-for-Sale	Amount of cash inflow from maturity, prepayment and call of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).
Gain Loss On Sale Of Derivatives	us-gaap/2024	0	monetary	D	C	Gain (Loss) on Sale of Derivatives	The difference between the book value and the sale price of options, swaps, futures, forward contracts, and other derivative instruments. This element refers to the gain (loss) included in earnings.
Expense	0001628280-25-020465	1	monetary	D	D	Expense	Expense.
Paymentsfor Proceedsfrom Investing Activities Netof Cash	0001628280-25-020465	1	monetary	D	C	Payments for (Proceeds from) Investing Activities, Net of Cash	Payments for (Proceeds from) Investing Activities, Net of Cash
Short Term Investments Trading Amortized Cost	0001628280-25-020465	1	monetary	I	D	Short Term Investments Trading Amortized Cost	Short-term investments, trading, amortized cost.
Fixed Income Debt Securities Available For Sale Including Related Party Investments	0001628280-25-020463	1	monetary	I	D	Fixed Income Debt Securities, Available for Sale, Including Related Party Investments	Fixed Income Debt Securities, Available for Sale, Including Related Party Investments
Accounts Payable Current And Noncurrent	us-gaap/2024	0	monetary	I	C	Accounts Payable	Carrying value as of the balance sheet date of liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business.
Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations	us-gaap/2024	0	monetary	I	D	Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Including Disposal Group and Discontinued Operations	Amount of cash and cash equivalents, and cash and cash equivalents restricted to withdrawal or usage; including, but not limited to, disposal group and discontinued operations. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. Cash equivalents include, but are not limited to, short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.
Derivative Assets	us-gaap/2024	0	monetary	I	D	Derivative Asset	Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.
Earnings Per Share Basic	us-gaap/2024	0	perShare	D		Earnings Per Share, Basic	The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.
Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments	us-gaap/2024	0	monetary	D	C	Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest	Amount of income (loss) from continuing operations before deduction of income tax expense (benefit) and income (loss) attributable to noncontrolling interest, and addition of income (loss) from equity method investments.
Operating Lease Impairment Loss	us-gaap/2024	0	monetary	D	D	Operating Lease, Impairment Loss	Amount of loss from impairment of right-of-use asset from operating lease.
Increase Decrease In Unearned Premiums	us-gaap/2024	0	monetary	D	D	Increase (Decrease) in Unearned Premiums	Amount of increase (decrease) unearned premiums written. Excludes portion of unearned premiums amortized into income.
Other Investments	us-gaap/2024	0	monetary	I	D	Other Investments	Amount of investments classified as other.
Net Cash Provided By Used In Investing Activities	us-gaap/2024	0	monetary	D	D	Net Cash Provided by (Used in) Investing Activities	Amount of cash inflow (outflow) from investing activities, including discontinued operations. Investing activity cash flows include making and collecting loans and acquiring and disposing of debt or equity instruments and property, plant, and equipment and other productive assets.
Reinsurance Payable	us-gaap/2024	0	monetary	I	C	Reinsurance Payable	The carrying amount as of the balance sheet date of the known and estimated amounts owed to insurers under reinsurance treaties or other arrangements.
Net Investment Income	us-gaap/2024	0	monetary	D	C	Net Investment Income	Amount, after investment expense, of income earned from investments in securities and real estate. Includes, but is not limited to, real estate investment, policy loans, dividends, and interest. Excludes realized gain (loss) on investments.
Reinsurance Recoverables On Paid And Unpaid Losses	us-gaap/2024	0	monetary	I	D	Reinsurance Recoverable for Paid and Unpaid Claims and Claims Adjustments	Amount, after valuation allowance, recoverable under reinsurance contracts. Examples include, but are not limited to, settled and unsettled claims, incurred but not reported losses, loss adjustment expense, policy benefits and policy reserves. Excludes premiums paid under reinsurance contracts.
Stock Issued During Period Value New Issues	us-gaap/2024	0	monetary	D	C	Stock Issued During Period, Value, New Issues	Equity impact of the value of new stock issued during the period. Includes shares issued in an initial public offering or a secondary public offering.
Cash And Cash Equivalents Includes Restricted Cash	0001628280-25-020465	1	monetary	I	D	Cash and cash equivalents includes restricted cash	Cash and cash equivalents includes restricted cash
Fixed Income Debt Securities Available For Sale Amortized Cost	0001628280-25-020465	1	monetary	I	D	Fixed Income Debt Securities, Available-for-Sale, Amortized Cost	Fixed Income Debt Securities, Available-for-Sale, Amortized Cost
Fixed Income Debt Securities Trading	0001628280-25-020465	1	monetary	I	D	Fixed Income Debt Securities, Trading	Fixed Income Debt Securities, Trading
Gains Losses On Investment And Foreign Exchange	0001628280-25-020465	1	monetary	D	C	Gains (Losses) On Investment And Foreign Exchange	Gains (losses) on investment and foreign exchange.
Increase Decrease In Derivative Instruments	0001628280-25-020465	1	monetary	D	D	Increase (Decrease) in Derivative Instruments	Fair value of derivatives and settlement of liabilities under derivatives.
Increase Decrease In Unpaid Losses Recoverable From Reinsurers	0001628280-25-020465	1	monetary	D	D	Increase (Decrease) in Unpaid Losses Recoverable from Reinsurers	Increase (Decrease) in Unpaid Losses Recoverable from Reinsurers
Privatelyheld Investments	0001628280-25-020463	1	monetary	I	D	Privately-held Investments	Privately-held Investments
Privately Held Investments Amortized Cost Trading At Fair Value	0001628280-25-020463	1	monetary	I	D	Privately-held investments, amortized cost, trading at fair value	Privately-held investments, amortized cost, trading at fair value
Short Term Investments Available For Sale	0001628280-25-020463	1	monetary	I	D	Short-term investments, available for sale	Short-term investments, available for sale
Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax	us-gaap/2024	0	monetary	D	D	OCI, Debt Securities, Available-for-Sale, Unrealized Holding Gain (Loss), before Adjustment, Tax	Amount, before adjustment, of tax expense (benefit) for unrealized holding gain (loss) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). Excludes tax expense (benefit) for unrealized gain (loss) on investment in debt security measured at amortized cost (held-to-maturity) from transfer to available-for-sale.
Derivative Gain Loss On Derivative Net	us-gaap/2024	0	monetary	D	C	Derivative, Gain (Loss) on Derivative, Net	Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.
Increase Decrease In Accrued Liabilities	us-gaap/2024	0	monetary	D	D	Increase (Decrease) in Accrued Liabilities	The increase (decrease) during the reporting period in the aggregate amount of expenses incurred but not yet paid.
Increase Decrease In Deferred Policy Acquisition Costs	us-gaap/2024	0	monetary	D	C	Increase (Decrease) in Deferred Policy Acquisition Costs	The increase (decrease) during the reporting period in the balance sheet value of capitalized sales costs that are associated with acquiring a new insurance customers.
Other Assets	us-gaap/2024	0	monetary	I	D	Other Assets	Amount of assets classified as other.
Other Comprehensive Income Loss Before Tax	us-gaap/2024	0	monetary	D	C	Other Comprehensive Income (Loss), before Tax	Amount before tax, after reclassification adjustments of other comprehensive income (loss).
Payments Of Dividends Common Stock	us-gaap/2024	0	monetary	D	C	Payments of Ordinary Dividends, Common Stock	Amount of cash outflow in the form of ordinary dividends to common shareholders of the parent entity.
Payments Of Dividends Preferred Stock And Preference Stock	us-gaap/2024	0	monetary	D	C	Payments of Ordinary Dividends, Preferred Stock and Preference Stock	Amount of cash outflow in the form of ordinary dividends to preferred shareholders of the parent entity.
Reclassification From Aoci Current Period Tax	us-gaap/2024	0	monetary	D	C	Reclassification from AOCI, Current Period, Tax	Amount of tax expense (benefit) of reclassification adjustment from accumulated other comprehensive income (loss).
Payments To Acquire Short Term Investments	us-gaap/2024	0	monetary	D	C	Payments to Acquire Short-Term Investments	The cash outflow for securities or other assets acquired, which qualify for treatment as an investing activity and are to be liquidated, if necessary, within the current operating cycle. Includes cash flows from securities classified as trading securities that were acquired for reasons other than sale in the short-term.
Net Changein Receivablefor Securities Soldor Payablefor Securities Purchased	0001628280-25-020465	1	monetary	D	D	Net Change in Receivable for Securities Sold or Payable for Securities Purchased	Net Change in Receivable for Securities Sold or Payable for Securities Purchased
Purchases Of Privately Held Investments Available For Sale	0001628280-25-020465	1	monetary	D	C	(Purchases of) privately-held investments, available for sale	(Purchases of) privately-held investments, available for sale
Short Term Investments Available For Sale	0001628280-25-020465	1	monetary	I	D	Short-term investments, available for sale	Short-term investments, available for sale
Increase Decrease In Derivative Instruments	0001628280-25-020463	1	monetary	D	D	Increase (Decrease) in Derivative Instruments	Fair value of derivatives and settlement of liabilities under derivatives.
Interest On Operating Lease Liabilities	0001628280-25-020463	1	monetary	D	D	Interest on operating lease liabilities	Interest on operating lease liabilities

Description

Field Name	Field Description
tag	The unique identifier (name) for a tag in a specific taxonomy release.
version	For a standard tag, an identifier for the taxonomy; otherwise the accession number where the tag was defined.
custom	1 if tag is custom (version=adsh), 0 if it is standard. Note: This flag is technically redundant with the version and adsh columns.
abstract	1 if the tag is not used to represent a numeric fact.
datatype	If abstract=1, then NULL, otherwise the data type (e.g., monetary) for the tag.
iord	If abstract=1, then NULL; otherwise, “I” if the value is a point-in time, or “D” if the value is a duration.
crdr	If datatype = monetary, then the tag’s natural accounting balance (debit or credit); if not defined, then NULL.
tlabel	If a standard tag, then the label text provided by the taxonomy, otherwise the text provided by the filer. A tag which had neither would have a NULL value here.
doc	The detailed definition for the tag. If a standard tag, then the text provided by the taxonomy, otherwise the text assigned by the filer. Some tags have neither, and this field is NULL.

Presentation of Statements

adsh	report	line	stmt	inpth	rfile	tag	version	plabel	negating
0001628280-25-020465	3	21	BS	1	H	Privately Held Investments Amortized Cost Available For Sale	0001628280-25-020465	Privately-held investments, available for sale, amortized cost	0
0001628280-25-020463	2	3	BS	0	H	Fixed Income Debt Securities Available For Sale	0001628280-25-020463	Fixed income securities, available-for-sale	0
0001628280-25-020463	2	4	BS	0	H	Fixed Income Debt Securities Trading	0001628280-25-020463	Fixed income securities, trading	0
0001628280-25-020463	2	5	BS	0	H	Short Term Investments Available For Sale	0001628280-25-020463	Short-term investments, available for sale	0
0001628280-25-020463	2	6	BS	0	H	Short Term Investments Trading At Fair Value	0001628280-25-020463	Short-term investments, trading at fair value	0
0001628280-25-020463	2	7	BS	0	H	Catastrophe Bond	0001628280-25-020463	Catastrophe bonds, trading at fair value (amortized cost 2024: $1.0 and 2023: $1.6)	0
0001628280-25-020463	2	8	BS	0	H	Privately Held Investments Available For Sale At Fair Value	0001628280-25-020463	Privately-held Investments, available for sale, at fair value	0
0001628280-25-020463	2	9	BS	0	H	Privatelyheld Investments	0001628280-25-020463	Privately-held Investments	0
0001628280-25-020463	2	10	BS	0	H	Equity Method Investments	us-gaap/2024	Investments, equity method	0
0001628280-25-020463	2	11	BS	0	H	Other Investments	us-gaap/2024	Other Investments	0
0001628280-25-020463	2	12	BS	0	H	Investments Excluding Derivative Assets	0001628280-25-020463	Investments, Excluding Derivative Assets	0
0001628280-25-020463	8	60	CF	0	H	Income Taxes Paid Net	us-gaap/2024	Income taxes paid	0
0001628280-25-020463	2	14	BS	0	H	Cash And Cash Equivalents At Carrying Value	us-gaap/2024	Cash and Cash Equivalents, at Carrying Value	0
0001628280-25-020463	2	15	BS	0	H	Reinsurance Recoverables On Paid And Unpaid Losses	us-gaap/2024	Unpaid losses recoverable from reinsurers (net of allowance for expected credit losses of 2024: $27.5 and 2023: $3.7)	0
0001628280-25-020463	2	16	BS	0	H	Prepaid Reinsurance Premiums	us-gaap/2024	Ceded unearned premiums	0
0001628280-25-020463	2	18	BS	0	H	Premiums Receivable At Carrying Value	us-gaap/2024	Underwriting premiums receivables (net of allowance for expected credit losses of 2024: $24.6 and 2023: $21.0)	0
0001628280-25-020463	2	19	BS	0	H	Deferred Policy Acquisition Costs	us-gaap/2024	Deferred acquisition costs	0
0001628280-25-020463	2	20	BS	0	H	Derivative Assets	us-gaap/2024	Derivative assets	0
0001628280-25-020463	2	21	BS	0	H	Operating Lease Right Of Use Asset	us-gaap/2024	Right-of-use operating lease assets	0
0001628280-25-020463	2	22	BS	0	H	Income Tax Receivable	us-gaap/2024	Income taxes refundable	0
0001628280-25-020463	2	23	BS	0	H	Deferred Income Tax Assets Net	us-gaap/2024	Deferred tax assets	0
0001628280-25-020463	2	24	BS	0	H	Other Assets	us-gaap/2024	Other assets	0
0001628280-25-020463	2	25	BS	0	H	Intangible Assets Net Including Goodwill	us-gaap/2024	Intangible assets and goodwill	0
0001628280-25-020463	2	26	BS	0	H	Assets	us-gaap/2024	Total assets	0
0001628280-25-020463	2	29	BS	0	H	Liability For Claims And Claims Adjustment Expense	us-gaap/2024	Reserve for losses and loss adjustment expenses	0
0001628280-25-020463	2	30	BS	0	H	Unearned Premiums	us-gaap/2024	Unearned premiums	0
0001628280-25-020463	2	31	BS	0	H	Insurance Reserves	0001628280-25-020463	Total insurance reserves	0
0001628280-25-020463	2	32	BS	0	H	Reinsurance Payable	us-gaap/2024	Reinsurance premiums	0
0001628280-25-020463	2	34	BS	0	H	Accrued Income Taxes Current	us-gaap/2024	Income taxes payable	0
0001628280-25-020463	2	35	BS	0	H	Deferred Income Tax Liabilities Net	us-gaap/2024	Deferred tax liabilities	0
0001628280-25-020463	2	36	BS	0	H	Accrued Liabilities Current And Noncurrent	us-gaap/2024	Accrued expenses and other payables	0
0001628280-25-020463	2	37	BS	0	H	Accounts Payable Current And Noncurrent	us-gaap/2024	Payables for securities purchased	0
0001628280-25-020463	2	38	BS	0	H	Operating Lease Liability	us-gaap/2024	Operating lease liabilities	0
0001628280-25-020463	2	39	BS	0	H	Derivative Liabilities	us-gaap/2024	Derivative liabilities	0
0001628280-25-020463	2	40	BS	0	H	Short Term Borrowings	us-gaap/2024	Short-Term Debt	0
0001628280-25-020463	2	41	BS	0	H	Liabilities	us-gaap/2024	Total liabilities	0
0001628280-25-020463	2	42	BS	0	H	Commitments And Contingencies	us-gaap/2024	Commitments and contingent liabilities	0
0001628280-25-020463	2	45	BS	0	H	Common Stock Value	us-gaap/2024	Ordinary shares, value	0
0001628280-25-020463	2	46	BS	0	H	Preferred Stock Value	us-gaap/2024	Preference shares, value	0
0001628280-25-020463	2	47	BS	0	H	Additional Paid In Capital	us-gaap/2024	Additional paid-in capital	0
0001628280-25-020463	2	48	BS	0	H	Retained Earnings Accumulated Deficit	us-gaap/2024	Retained earnings	0
0001628280-25-020463	2	49	BS	0	H	Accumulated Other Comprehensive Income Loss Net Of Tax	us-gaap/2024	Accumulated other comprehensive (loss)	0
0001628280-25-020463	2	50	BS	0	H	Stockholders Equity Including Portion Attributable To Noncontrolling Interest	us-gaap/2024	Total shareholders' equity	0
0001628280-25-020463	2	51	BS	0	H	Liabilities And Stockholders Equity	us-gaap/2024	Total liabilities and shareholders equity	0
0001628280-25-020463	3	15	BS	1	H	Fixed Income Debt Securities Available For Sale Allowance For Credit Loss	0001628280-25-020463	Net allowance, available for sale maturities, for expected credit losses	0
0001628280-25-020463	3	16	BS	1	H	Fixed Income Debt Securities Available For Sale Amortized Cost	0001628280-25-020463	Fixed income securities, available for sale amortized cost	0
0001628280-25-020463	3	17	BS	1	H	Fixed Income Debt Securities Trading Amortized Cost	0001628280-25-020463	Fixed income securities, trading, amortized cost	0
0001628280-25-020463	3	18	BS	1	H	Shortterminvestmentsavailableforsaleamortizedcost	0001628280-25-020463	Short term investments available for sale, amortized cost	0
0001628280-25-020463	3	19	BS	1	H	Short Term Investments Trading Amortized Cost	0001628280-25-020463	Short-term investments, trading, amortized cost	0
0001628280-25-020463	3	20	BS	1	H	Catastrophe Bonds Fair Value Disclosure	0001628280-25-020463	Catastrophe Bonds, Fair Value Disclosure	0
0001628280-25-020463	3	21	BS	1	H	Privately Held Investments Amortized Cost Available For Sale	0001628280-25-020463	Privately-held investments, available for sale, amortized cost	0
0001628280-25-020463	3	22	BS	1	H	Privately Held Investments Amortized Cost Trading At Fair Value	0001628280-25-020463	Privately-held investments, cost, trading at fair value	0
0001628280-25-020463	3	23	BS	1	H	Reinsurance Recoverables Allowance	us-gaap/2024	Unpaid losses recoverable from reinsurers (net of allowance for expected credit losses of 2024: $27.5 and 2023: $3.7)	0
0001628280-25-020463	3	24	BS	1	H	Premiums Receivable Allowance For Doubtful Accounts	us-gaap/2024	Underwriting premiums receivables, allowance for expected credit losses	0
0001628280-25-020463	3	25	BS	1	H	Fixed Income Debt Securities Available For Sale Including Related Party Investments	0001628280-25-020463	Fixed income securities, AFS , RP	0
0001628280-25-020463	3	26	BS	1	H	Fixed Income Debt Securities Trading	0001628280-25-020463	Fixed income securities, trading	0
0001628280-25-020463	3	27	BS	1	H	Privatelyheld Investments	0001628280-25-020463	Privately-held Investments	0
0001628280-25-020463	3	28	BS	1	H	Privately Held Investments Available For Sale At Fair Value	0001628280-25-020463	Privately-held Investments, available for sale, at fair value	0
0001628280-25-020463	3	29	BS	1	H	Other Investments	us-gaap/2024	Other Investments	0
0001628280-25-020463	3	30	BS	1	H	Cash And Cash Equivalents Includes Restricted Cash	0001628280-25-020463	Restricted cash	0
0001628280-25-020463	3	31	BS	1	H	Accrued Liabilities Current And Noncurrent	us-gaap/2024	Accrued expenses and other payables	0
0001628280-25-020463	4	2	IS	0	H	Premiums Earned Net	us-gaap/2024	Net earned premiums	0
0001628280-25-020463	4	3	IS	0	H	Net Investment Income	us-gaap/2024	Net investment income (1)	0
0001628280-25-020463	4	4	IS	0	H	Gain Loss On Investments	us-gaap/2024	Gain (loss) on investments	0
0001628280-25-020463	4	5	IS	0	H	Other Income	us-gaap/2024	Other income	0
0001628280-25-020463	4	6	IS	0	H	Revenues	us-gaap/2024	Total revenues	0
0001628280-25-020463	4	8	IS	0	H	Policyholder Benefits And Claims Incurred Net	us-gaap/2024	Losses and loss adjustment expenses	0
0001628280-25-020463	4	9	IS	0	H	Deferred Policy Acquisition Cost Amortization Expense	us-gaap/2024	Acquisition costs	0
0001628280-25-020463	4	10	IS	0	H	Selling General And Administrative Expense	us-gaap/2024	General, administrative and corporate expenses (3)	0
0001628280-25-020463	4	11	IS	0	H	Interest Expense Debt	us-gaap/2024	Interest expense	0
0001628280-25-020463	4	12	IS	0	H	Derivative Gain Loss On Derivative Net	us-gaap/2024	Change in fair value of derivatives	1
0001628280-25-020463	4	13	IS	0	H	Debt Securities Gain Loss	us-gaap/2024	Realized and unrealized investment losses	1
0001628280-25-020463	4	14	IS	0	H	Foreign Currency Transaction Gain Loss Before Tax	us-gaap/2024	Net realized and unrealized foreign exchange (gains)/losses	0
0001628280-25-020463	4	15	IS	0	H	Other Expenses	us-gaap/2024	Other expenses	0
0001628280-25-020463	4	16	IS	0	H	Expense	0001628280-25-020463	Total expenses	0
0001628280-25-020463	4	17	IS	0	H	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments	us-gaap/2024	Income (loss) from operations before income taxes	0
0001628280-25-020463	4	18	IS	0	H	Income Tax Expense Benefit	us-gaap/2024	Income tax benefit	1
0001628280-25-020463	4	19	IS	0	H	Net Income Loss	us-gaap/2024	Net Income (Loss) Attributable to Parent, Total	0
0001628280-25-020463	4	22	IS	0	H	Reclassification From Accumulated Other Comprehensive Income Current Period Before Tax	us-gaap/2024	Reclassification adjustment for net realized losses on investments included in net income	1
0001628280-25-020463	4	23	IS	0	H	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax	us-gaap/2024	Change in net unrealized (losses)/gains on available for sale securities held	0
0001628280-25-020463	4	24	IS	0	H	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Before Tax	us-gaap/2024	Net change from current period hedged transactions	0
0001628280-25-020463	4	25	IS	0	H	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Before Tax	us-gaap/2024	Change in foreign currency translation adjustment	0
0001628280-25-020463	4	26	IS	0	H	Other Comprehensive Income Loss Before Tax	us-gaap/2024	Other comprehensive (loss)/income, before income taxes	0
0001628280-25-020463	4	28	IS	0	H	Reclassification From Aoci Current Period Tax	us-gaap/2024	Reclassification adjustment for net realized losses on investments included in net income	0
0001628280-25-020463	4	29	IS	0	H	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax	us-gaap/2024	Change in net unrealized losses/(gains) on available for sale securities held	1
0001628280-25-020463	4	30	IS	0	H	Other Comprehensive Income Loss Tax Portion Attributable To Parent1	us-gaap/2024	Total income tax (expense)/benefit allocated to other comprehensive income/(loss)	1
0001628280-25-020463	4	31	IS	0	H	Other Comprehensive Income Loss Net Of Tax	us-gaap/2024	Other comprehensive income/(loss), net of tax	0
0001628280-25-020463	4	32	IS	0	H	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Tax	us-gaap/2024	Net change from current period hedged transactions	1
0001628280-25-020463	4	33	IS	0	H	Comprehensive Income Net Of Tax	us-gaap/2024	Total comprehensive (loss)/income attributable to Aspen Insurance Holdings Limited's ordinary shareholders	0
0001628280-25-020463	4	35	IS	0	H	Net Income Loss	us-gaap/2024	Net income	0
0001628280-25-020463	4	36	IS	0	H	Redeemable Preferred Stock Dividends	us-gaap/2024	Preference share dividends	0
0001628280-25-020463	4	37	IS	0	H	Net Income Loss From Continuing Operations Available To Common Shareholders Basic	us-gaap/2024	Net income available to Aspen Insurance Holdings Limiteds ordinary shareholders	0
0001628280-25-020463	4	38	IS	0	H	Earnings Per Share Basic	us-gaap/2024	Basic earning per ordinary share (in usd per share)	0
0001628280-25-020463	4	39	IS	0	H	Earnings Per Share Diluted	us-gaap/2024	Diluted earnings per ordinary share (in usd per share)	0
0001628280-25-020463	5	11	IS	1	H	Net Investment Income	us-gaap/2024	Net investment income (1)	0
0001628280-25-020463	5	12	IS	1	H	Debt Securities Gain Loss	us-gaap/2024	Realized and unrealized investment losses	0
0001628280-25-020463	5	13	IS	1	H	General And Administrative Expense	us-gaap/2024	General and administrative expenses	0
0001628280-25-020463	6	17	EQ	0	H	Stockholders Equity Including Portion Attributable To Noncontrolling Interest	us-gaap/2024	Beginning balance	0
0001628280-25-020463	6	18	EQ	0	H	Profit Loss	us-gaap/2024	Net income/(loss) for the year	0
0001628280-25-020463	6	19	EQ	0	H	Dividends	us-gaap/2024	Dividends	1
0001628280-25-020463	6	20	EQ	0	H	Redeemable Preferred Stock Dividends	us-gaap/2024	Preference share dividends	0
0001628280-25-020463	6	21	EQ	0	H	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax	us-gaap/2024	Change for the year, net of income taxes	0
0001628280-25-020463	6	22	EQ	0	H	Stock Issued During Period Value New Issues	us-gaap/2024	Shares issued	0
0001628280-25-020463	6	23	EQ	0	H	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax Parent	us-gaap/2024	Net change from current period hedged transactions	0
0001628280-25-020463	6	24	EQ	0	H	Accumulated Other Comprehensive Income Loss Net Of Tax	us-gaap/2024	Total accumulated other comprehensive (loss)/income	0
0001628280-25-020463	6	25	EQ	0	H	Stockholders Equity Including Portion Attributable To Noncontrolling Interest	us-gaap/2024	Ending balance	0
0001628280-25-020463	7	5	EQ	1	H	Aggregate Liquidation Preference Shares	0001628280-25-020463	Aggregate Liquidation Preference Shares	0
0001628280-25-020463	7	6	EQ	1	H	Preferred Stock Issuance Cost	0001628280-25-020463	Preferred Stock Issuance Cost	0
0001628280-25-020463	8	2	CF	0	H	Profit Loss	us-gaap/2024	Net income/(loss)	0
0001628280-25-020463	8	4	CF	0	H	Depreciation Amortization And Accretion Net	us-gaap/2024	Depreciation and amortization	0
0001628280-25-020463	8	5	CF	0	H	Operating Lease Impairment Loss	us-gaap/2024	Impairment of lease assets	0
0001628280-25-020463	8	6	CF	0	H	Finance Lease Right Of Use Asset Amortization	us-gaap/2024	Amortization of right-of-use operating lease assets	0
0001628280-25-020463	8	7	CF	0	H	Interest On Operating Lease Liabilities	0001628280-25-020463	Interest on operating lease liabilities	0
0001628280-25-020463	8	8	CF	0	H	Gain Loss On Investments	us-gaap/2024	Realized and unrealized investment gains	1
0001628280-25-020463	8	9	CF	0	H	Debt Securities Gain Loss	us-gaap/2024	Realized and unrealized investment losses	1
0001628280-25-020463	8	10	CF	0	H	Increase Decrease In Deferred Income Taxes	us-gaap/2024	Deferred tax expense/(benefit)	1
0001628280-25-020463	8	11	CF	0	H	Gains Losses On Investment And Foreign Exchange	0001628280-25-020463	Net realized and unrealized investment foreign exchange losses/(gains)	1
0001628280-25-020463	8	12	CF	0	H	Gain Loss On Sale Of Derivatives	us-gaap/2024	Net change from current period hedged transactions	1
0001628280-25-020463	8	13	CF	0	H	Unrealized Gainloss On Real Estate Fund In Net Investment Income	0001628280-25-020463	Unrealized (gain)/loss on real estate fund in net investment income	1
0001628280-25-020463	8	15	CF	0	H	Increase Decrease In Liability For Claims And Claims Adjustment Expense Reserve	us-gaap/2024	Reserve for losses and loss adjustment expenses	0
0001628280-25-020463	8	16	CF	0	H	Increase Decrease In Unearned Premiums	us-gaap/2024	Unearned premiums	0
0001628280-25-020463	8	17	CF	0	H	Increase Decrease In Unpaid Losses Recoverable From Reinsurers	0001628280-25-020463	Unpaid losses recoverable from reinsurers	0
0001628280-25-020463	8	18	CF	0	H	Increase Decrease In Prepaid Reinsurance Premiums	us-gaap/2024	Ceded unearned premiums	1
0001628280-25-020463	8	19	CF	0	H	Increase Decrease In Deferred Policy Acquisition Costs	us-gaap/2024	Deferred acquisition costs	1
0001628280-25-020463	8	20	CF	0	H	Increase Decrease In Reinsurance Payables	us-gaap/2024	Reinsurance premiums payable	0
0001628280-25-020463	8	21	CF	0	H	Increase Decrease In Premiums Receivable	us-gaap/2024	Underwriting premiums receivable	1
0001628280-25-020463	8	22	CF	0	H	Increase Decrease In Accrued Income Taxes Payable	us-gaap/2024	Income tax payable and refundable	0
0001628280-25-020463	8	23	CF	0	H	Increase Decrease In Accrued Liabilities	us-gaap/2024	Accrued expenses and other payables	0
0001628280-25-020463	8	24	CF	0	H	Increase Decrease In Derivative Instruments	0001628280-25-020463	Derivative assets and derivative liabilities	0
0001628280-25-020463	8	25	CF	0	H	Operating Lease Payments	us-gaap/2024	Operating lease liabilities	1
0001628280-25-020463	8	26	CF	0	H	Increase Decrease In Other Operating Assets	us-gaap/2024	Other	1
0001628280-25-020463	8	27	CF	0	H	Net Cash Provided By Used In Operating Activities	us-gaap/2024	Net cash provided by/(used in) operating activities	0
0001628280-25-020463	8	29	CF	0	H	Payments To Acquire Available For Sale Securities Debt	us-gaap/2024	(Purchases) of fixed income securities Available for sale	1
0001628280-25-020463	8	30	CF	0	H	Payments To Acquire Trading Securities Heldforinvestment	us-gaap/2024	(Purchases) of fixed income securities Trading	1
0001628280-25-020463	8	31	CF	0	H	Proceeds From Sale Of Available For Sale Securities Debt	us-gaap/2024	Proceeds from sales and maturities of fixed income securities Available for sale	0
0001628280-25-020463	8	32	CF	0	H	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities	us-gaap/2024	Proceeds from sales and maturities of fixed income securities Trading	0
0001628280-25-020463	8	33	CF	0	H	Purchases Of Proceeds From Catastrophe Bonds	0001628280-25-020463	Net proceeds from catastrophe bonds Trading	1
0001628280-25-020463	8	34	CF	0	H	Paymentsfor Availableforsale Securities Shortterm	0001628280-25-020463	(Purchases) of short-term investments Available for sale	1
0001628280-25-020463	8	35	CF	0	H	Proceedsfrom Availableforsale Securities Shortterm	0001628280-25-020463	Proceeds from sale of short-term investments Available for sale	0
0001628280-25-020463	8	36	CF	0	H	Payments To Acquire Short Term Investments	us-gaap/2024	(Purchases) of short-term investments Trading	1
0001628280-25-020463	8	37	CF	0	H	Proceeds From Sale Of Short Term Investments	us-gaap/2024	Proceeds from sale of short-term investments Trading	0
0001628280-25-020463	8	38	CF	0	H	Purchases Of Privately Held Investments Available For Sale	0001628280-25-020463	(Purchases) of privately-held investments - Available for sale	1
0001628280-25-020463	8	39	CF	0	H	Payments To Acquire Privately Held Investments Trading	0001628280-25-020463	(Purchases) of privately-held investments Trading	1
0001628280-25-020463	8	40	CF	0	H	Proceedsfrom Saleof Privatelyheld Investments	0001628280-25-020463	Proceeds from sale of privately-held investments Trading	0
0001628280-25-020463	8	41	CF	0	H	Net Changein Receivablefor Securities Soldor Payablefor Securities Purchased	0001628280-25-020463	Net change in receivable/(payable) for securities sold/(purchased)	0
0001628280-25-020463	8	42	CF	0	H	Payments For Proceeds From Other Investing Activities	us-gaap/2024	(Purchases) of other investments	1
0001628280-25-020463	8	43	CF	0	H	Paymentsfor Proceedsfrom Investing Activities Netof Cash	0001628280-25-020463	Net proceeds from sales of other investments	1
0001628280-25-020463	8	44	CF	0	H	Payments For Proceeds From Productive Assets	us-gaap/2024	Net (purchases)/sales of fixed assets	0
0001628280-25-020463	8	45	CF	0	H	Payments To Acquire Equity Method Investments	us-gaap/2024	Net (purchases) of investments, equity method	1
0001628280-25-020463	8	46	CF	0	H	Net Cash Provided By Used In Investing Activities	us-gaap/2024	Net cash (used in) investing activities	0
0001628280-25-020463	8	48	CF	0	H	Repayments Of Short Term Debt	us-gaap/2024	Repayments of Short-Term Debt	1
0001628280-25-020463	8	49	CF	0	H	Proceeds From Term Loan Facility	0001628280-25-020463	Proceeds from term loan facility	0
0001628280-25-020463	8	50	CF	0	H	Payments For Repurchase Of Preferred Stock And Preference Stock	us-gaap/2024	Redemption of preference shares (2)	1
0001628280-25-020463	8	51	CF	0	H	Proceeds From Issuance Of Preferred Stock And Preference Stock	us-gaap/2024	Preference share issuance	0
0001628280-25-020463	8	52	CF	0	H	Payments Of Dividends Common Stock	us-gaap/2024	Payments of Ordinary Dividends, Common Stock	0
0001628280-25-020463	8	53	CF	0	H	Payments Of Dividends Preferred Stock And Preference Stock	us-gaap/2024	Dividends paid on preference shares	1
0001628280-25-020463	8	54	CF	0	H	Net Cash Provided By Used In Financing Activities	us-gaap/2024	Net cash (used in) financing activities	0
0001628280-25-020463	8	55	CF	0	H	Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents	us-gaap/2024	Effect of exchange rate movements on cash and cash equivalents	0
0001628280-25-020463	8	56	CF	0	H	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect	us-gaap/2024	(Decrease)/Increase in cash and cash equivalents	0
0001628280-25-020463	8	57	CF	0	H	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations	us-gaap/2024	Cash and cash equivalents at beginning of period	0
0001628280-25-020463	8	58	CF	0	H	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations	us-gaap/2024	Cash and cash equivalents at end of period	0
0001628280-25-020463	8	61	CF	0	H	Interest Paid	us-gaap/2024	Interest paid	0
0001628280-25-020463	9	9	CF	1	H	Preferred Stock Shares Issued	us-gaap/2024	Preferred Stock, Shares Issued	0
0001628280-25-020463	9	10	CF	1	H	Preferred Stock Dividend Rate Percentage	us-gaap/2024	Preferred Stock, Dividend Rate, Percentage	0
0001628280-25-020463	9	11	CF	1	H	Preferred Stock Liquidation Preference Value	us-gaap/2024	Preference shares liquidation preference, value	0
0001628280-25-020463	9	12	CF	1	H	Cash And Cash Equivalents Includes Restricted Cash	0001628280-25-020463	Restricted cash	0
0001628280-25-020465	2	3	BS	0	H	Fixed Income Debt Securities Available For Sale	0001628280-25-020465	Fixed income securities, available-for-sale	0
0001628280-25-020465	2	4	BS	0	H	Fixed Income Debt Securities Trading	0001628280-25-020465	Fixed income securities, trading	0
0001628280-25-020465	2	5	BS	0	H	Short Term Investments Available For Sale	0001628280-25-020465	Short-term investments, available for sale	0
0001628280-25-020465	2	6	BS	0	H	Short Term Investments Trading At Fair Value	0001628280-25-020465	Short-term investments, trading at fair value	0
0001628280-25-020465	2	7	BS	0	H	Catastrophe Bond	0001628280-25-020465	Catastrophe bonds, trading at fair value (amortized cost 2024: $1.0 and 2023: $1.6)	0
0001628280-25-020465	2	8	BS	0	H	Privately Held Investments Available For Sale At Fair Value	0001628280-25-020465	Privately-held Investments, available for sale, at fair value	0
0001628280-25-020465	2	9	BS	0	H	Privatelyheld Investments	0001628280-25-020465	Privately-held Investments	0
0001628280-25-020465	2	10	BS	0	H	Equity Method Investments	us-gaap/2024	Investments, equity method	0
0001628280-25-020465	2	11	BS	0	H	Other Investments	us-gaap/2024	Other Investments	0
0001628280-25-020465	2	12	BS	0	H	Investments Excluding Derivative Assets	0001628280-25-020465	Investments, Excluding Derivative Assets	0
0001628280-25-020465	2	14	BS	0	H	Cash And Cash Equivalents At Carrying Value	us-gaap/2024	Cash and Cash Equivalents, at Carrying Value	0
0001628280-25-020465	2	15	BS	0	H	Reinsurance Recoverables On Paid And Unpaid Losses	us-gaap/2024	Unpaid losses recoverable from reinsurers (net of allowance for expected credit losses of 2024: $27.5 and 2023: $3.7)	0
0001628280-25-020465	2	16	BS	0	H	Prepaid Reinsurance Premiums	us-gaap/2024	Ceded unearned premiums	0
0001628280-25-020465	2	18	BS	0	H	Premiums Receivable At Carrying Value	us-gaap/2024	Underwriting premiums receivables (net of allowance for expected credit losses of 2024: $24.6 and 2023: $21.0)	0
0001628280-25-020465	2	19	BS	0	H	Deferred Policy Acquisition Costs	us-gaap/2024	Deferred acquisition costs	0
0001628280-25-020465	2	20	BS	0	H	Derivative Assets	us-gaap/2024	Derivative assets	0
0001628280-25-020465	2	21	BS	0	H	Operating Lease Right Of Use Asset	us-gaap/2024	Right-of-use operating lease assets	0
0001628280-25-020465	2	22	BS	0	H	Income Tax Receivable	us-gaap/2024	Income taxes refundable	0
0001628280-25-020465	2	23	BS	0	H	Deferred Income Tax Assets Net	us-gaap/2024	Deferred tax assets	0
0001628280-25-020465	2	24	BS	0	H	Other Assets	us-gaap/2024	Other assets	0
0001628280-25-020465	2	25	BS	0	H	Intangible Assets Net Including Goodwill	us-gaap/2024	Intangible assets and goodwill	0
0001628280-25-020465	2	26	BS	0	H	Assets	us-gaap/2024	Total assets	0
0001628280-25-020465	2	29	BS	0	H	Liability For Claims And Claims Adjustment Expense	us-gaap/2024	Reserve for losses and loss adjustment expenses	0
0001628280-25-020465	2	30	BS	0	H	Unearned Premiums	us-gaap/2024	Unearned premiums	0
0001628280-25-020465	2	31	BS	0	H	Insurance Reserves	0001628280-25-020465	Total insurance reserves	0
0001628280-25-020465	2	32	BS	0	H	Reinsurance Payable	us-gaap/2024	Reinsurance premiums	0
0001628280-25-020465	2	34	BS	0	H	Accrued Income Taxes Current	us-gaap/2024	Income taxes payable	0
0001628280-25-020465	2	35	BS	0	H	Deferred Income Tax Liabilities Net	us-gaap/2024	Deferred tax liabilities	0
0001628280-25-020465	2	36	BS	0	H	Accrued Liabilities Current And Noncurrent	us-gaap/2024	Accrued expenses and other payables	0
0001628280-25-020465	2	37	BS	0	H	Accounts Payable Current And Noncurrent	us-gaap/2024	Payables for securities purchased	0
0001628280-25-020465	2	38	BS	0	H	Operating Lease Liability	us-gaap/2024	Operating lease liabilities	0
0001628280-25-020465	2	39	BS	0	H	Derivative Liabilities	us-gaap/2024	Derivative liabilities	0
0001628280-25-020465	2	40	BS	0	H	Short Term Borrowings	us-gaap/2024	Short-Term Debt	0
0001628280-25-020465	2	41	BS	0	H	Liabilities	us-gaap/2024	Total liabilities	0
0001628280-25-020465	2	42	BS	0	H	Commitments And Contingencies	us-gaap/2024	Commitments and contingent liabilities	0
0001628280-25-020465	2	45	BS	0	H	Common Stock Value	us-gaap/2024	Ordinary shares, value	0
0001628280-25-020465	2	46	BS	0	H	Preferred Stock Value	us-gaap/2024	Preference shares, value	0
0001628280-25-020465	2	47	BS	0	H	Additional Paid In Capital	us-gaap/2024	Additional paid-in capital	0
0001628280-25-020465	2	48	BS	0	H	Retained Earnings Accumulated Deficit	us-gaap/2024	Retained earnings	0
0001628280-25-020465	2	49	BS	0	H	Accumulated Other Comprehensive Income Loss Net Of Tax	us-gaap/2024	Accumulated other comprehensive (loss)	0
0001628280-25-020465	2	50	BS	0	H	Stockholders Equity Including Portion Attributable To Noncontrolling Interest	us-gaap/2024	Total shareholders' equity	0
0001628280-25-020465	2	51	BS	0	H	Liabilities And Stockholders Equity	us-gaap/2024	Total liabilities and shareholders equity	0
0001628280-25-020465	3	15	BS	1	H	Fixed Income Debt Securities Available For Sale Allowance For Credit Loss	0001628280-25-020465	Net allowance, available for sale maturities, for expected credit losses	0
0001628280-25-020465	3	16	BS	1	H	Fixed Income Debt Securities Available For Sale Amortized Cost	0001628280-25-020465	Fixed income securities, available for sale amortized cost	0
0001628280-25-020465	3	17	BS	1	H	Fixed Income Debt Securities Trading Amortized Cost	0001628280-25-020465	Fixed income securities, trading, amortized cost	0
0001628280-25-020465	3	18	BS	1	H	Shortterminvestmentsavailableforsaleamortizedcost	0001628280-25-020465	Short term investments available for sale, amortized cost	0
0001628280-25-020465	3	19	BS	1	H	Short Term Investments Trading Amortized Cost	0001628280-25-020465	Short-term investments, trading, amortized cost	0
0001628280-25-020465	3	20	BS	1	H	Catastrophe Bonds Fair Value Disclosure	0001628280-25-020465	Catastrophe Bonds, Fair Value Disclosure	0
0001628280-25-020465	6	21	EQ	0	H	Redeemable Preferred Stock Dividends	us-gaap/2024	Dividends on preference shares	0
0001628280-25-020465	3	22	BS	1	H	Privately Held Investments Amortized Cost Trading At Fair Value	0001628280-25-020465	Privately-held investments, cost, trading at fair value	0
0001628280-25-020465	3	23	BS	1	H	Reinsurance Recoverables Allowance	us-gaap/2024	Unpaid losses recoverable from reinsurers (net of allowance for expected credit losses of 2024: $27.5 and 2023: $3.7)	0
0001628280-25-020465	3	24	BS	1	H	Premiums Receivable Allowance For Doubtful Accounts	us-gaap/2024	Premium Receivable, Allowance for Credit Loss	0
0001628280-25-020465	3	25	BS	1	H	Fixed Income Debt Securities Available For Sale Including Related Party Investments	0001628280-25-020465	Fixed income securities, AFS , RP	0
0001628280-25-020465	3	26	BS	1	H	Fixed Income Debt Securities Trading	0001628280-25-020465	Fixed income securities, trading	0
0001628280-25-020465	3	27	BS	1	H	Privatelyheld Investments	0001628280-25-020465	Privately-held Investments	0
0001628280-25-020465	3	28	BS	1	H	Privately Held Investments Available For Sale At Fair Value	0001628280-25-020465	Privately-held Investments, available for sale, at fair value	0
0001628280-25-020465	3	29	BS	1	H	Other Investments	us-gaap/2024	Other Investments	0
0001628280-25-020465	3	30	BS	1	H	Cash And Cash Equivalents Includes Restricted Cash	0001628280-25-020465	Restricted cash	0
0001628280-25-020465	3	31	BS	1	H	Accrued Liabilities Current And Noncurrent	us-gaap/2024	Accrued expenses and other payables	0
0001628280-25-020465	4	2	IS	0	H	Premiums Earned Net	us-gaap/2024	Net earned premiums	0
0001628280-25-020465	4	3	IS	0	H	Net Investment Income	us-gaap/2024	Net investment income (1)	0
0001628280-25-020465	4	4	IS	0	H	Gain Loss On Investments	us-gaap/2024	Gain (loss) on investments	0
0001628280-25-020465	4	5	IS	0	H	Other Income	us-gaap/2024	Other income	0
0001628280-25-020465	4	6	IS	0	H	Revenues	us-gaap/2024	Total revenues	0
0001628280-25-020465	4	8	IS	0	H	Policyholder Benefits And Claims Incurred Net	us-gaap/2024	Losses and loss adjustment expenses	0
0001628280-25-020465	4	9	IS	0	H	Deferred Policy Acquisition Cost Amortization Expense	us-gaap/2024	Acquisition costs	0
0001628280-25-020465	4	10	IS	0	H	Selling General And Administrative Expense	us-gaap/2024	General, administrative and corporate expenses (3)	0
0001628280-25-020465	4	11	IS	0	H	Interest Expense Debt	us-gaap/2024	Interest expense	0
0001628280-25-020465	4	12	IS	0	H	Derivative Gain Loss On Derivative Net	us-gaap/2024	Change in fair value of derivatives	1
0001628280-25-020465	4	13	IS	0	H	Debt Securities Gain Loss	us-gaap/2024	Realized and unrealized investment losses	1
0001628280-25-020465	4	14	IS	0	H	Foreign Currency Transaction Gain Loss Before Tax	us-gaap/2024	Net realized and unrealized foreign exchange (gains)/losses	0
0001628280-25-020465	4	15	IS	0	H	Other Expenses	us-gaap/2024	Other expenses	0
0001628280-25-020465	4	16	IS	0	H	Expense	0001628280-25-020465	Total expenses	0
0001628280-25-020465	4	17	IS	0	H	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments	us-gaap/2024	Income (loss) from operations before income taxes	0
0001628280-25-020465	4	18	IS	0	H	Income Tax Expense Benefit	us-gaap/2024	Income tax benefit	1
0001628280-25-020465	4	19	IS	0	H	Net Income Loss	us-gaap/2024	Net Income (Loss) Attributable to Parent, Total	0
0001628280-25-020465	4	22	IS	0	H	Reclassification From Accumulated Other Comprehensive Income Current Period Before Tax	us-gaap/2024	Reclassification adjustment for net realized losses on investments included in net income	1
0001628280-25-020465	4	23	IS	0	H	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax	us-gaap/2024	Change in net unrealized (losses)/gains on available for sale securities held	0
0001628280-25-020465	4	24	IS	0	H	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Before Tax	us-gaap/2024	Net change from current period hedged transactions	0
0001628280-25-020465	4	25	IS	0	H	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Before Tax	us-gaap/2024	Change in foreign currency translation adjustment	0
0001628280-25-020465	4	26	IS	0	H	Other Comprehensive Income Loss Before Tax	us-gaap/2024	Other comprehensive (loss)/income, before income taxes	0
0001628280-25-020465	4	28	IS	0	H	Reclassification From Aoci Current Period Tax	us-gaap/2024	Reclassification adjustment for net realized losses on investments included in net income	0
0001628280-25-020465	4	29	IS	0	H	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax	us-gaap/2024	Change in net unrealized losses/(gains) on available for sale securities held	1
0001628280-25-020465	4	30	IS	0	H	Other Comprehensive Income Loss Tax Portion Attributable To Parent1	us-gaap/2024	Total income tax (expense)/benefit allocated to other comprehensive income/(loss)	1
0001628280-25-020465	4	31	IS	0	H	Other Comprehensive Income Loss Net Of Tax	us-gaap/2024	Other comprehensive income/(loss), net of tax	0
0001628280-25-020465	4	32	IS	0	H	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Tax	us-gaap/2024	Net change from current period hedged transactions	1
0001628280-25-020465	4	33	IS	0	H	Comprehensive Income Net Of Tax	us-gaap/2024	Total comprehensive (loss)/income attributable to Aspen Insurance Holdings Limited's ordinary shareholders	0
0001628280-25-020465	4	35	IS	0	H	Net Income Loss	us-gaap/2024	Net income	0
0001628280-25-020465	4	36	IS	0	H	Redeemable Preferred Stock Dividends	us-gaap/2024	Dividends on preference shares	0
0001628280-25-020465	4	37	IS	0	H	Net Income Loss From Continuing Operations Available To Common Shareholders Basic	us-gaap/2024	Net income (loss) available to ordinary shareholders, basic	0
0001628280-25-020465	5	11	IS	1	H	Net Investment Income	us-gaap/2024	Net investment income (1)	0
0001628280-25-020465	5	12	IS	1	H	Debt Securities Gain Loss	us-gaap/2024	Realized and unrealized investment losses	0
0001628280-25-020465	5	13	IS	1	H	General And Administrative Expense	us-gaap/2024	General and administrative expenses	0
0001628280-25-020465	6	17	EQ	0	H	Stockholders Equity Including Portion Attributable To Noncontrolling Interest	us-gaap/2024	Equity, Including Portion Attributable to Noncontrolling Interest	0
0001628280-25-020465	6	18	EQ	0	H	Stock Issued During Period Value New Issues	us-gaap/2024	Shares issued	0
0001628280-25-020465	6	19	EQ	0	H	Profit Loss	us-gaap/2024	Net income/(loss) for the year	0
0001628280-25-020465	6	20	EQ	0	H	Dividends	us-gaap/2024	Dividends	1
0001628280-25-020465	6	22	EQ	0	H	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax	us-gaap/2024	Change for the year, net of income taxes	0
0001628280-25-020465	6	23	EQ	0	H	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax Parent	us-gaap/2024	Net change from current period hedged transactions	0
0001628280-25-020465	6	24	EQ	0	H	Accumulated Other Comprehensive Income Loss Net Of Tax	us-gaap/2024	Total accumulated other comprehensive (loss)/income	0
0001628280-25-020465	7	5	EQ	1	H	Aggregate Liquidation Preference Shares	0001628280-25-020465	Aggregate Liquidation Preference Shares	0
0001628280-25-020465	7	6	EQ	1	H	Preferred Stock Issuance Cost	0001628280-25-020465	Preferred Stock Issuance Cost	0
0001628280-25-020465	8	2	CF	0	H	Profit Loss	us-gaap/2024	Net income/(loss)	0
0001628280-25-020465	8	4	CF	0	H	Depreciation Amortization And Accretion Net	us-gaap/2024	Depreciation and amortization	0
0001628280-25-020465	8	5	CF	0	H	Operating Lease Impairment Loss	us-gaap/2024	Impairment of lease assets	0
0001628280-25-020465	8	6	CF	0	H	Finance Lease Right Of Use Asset Amortization	us-gaap/2024	Amortization of right-of-use operating lease assets	0
0001628280-25-020465	8	7	CF	0	H	Interest On Operating Lease Liabilities	0001628280-25-020465	Interest on operating lease liabilities	0
0001628280-25-020465	8	8	CF	0	H	Gain Loss On Investments	us-gaap/2024	Realized and unrealized investment gains	1
0001628280-25-020465	8	9	CF	0	H	Debt Securities Gain Loss	us-gaap/2024	Realized and unrealized investment losses	1
0001628280-25-020465	8	10	CF	0	H	Increase Decrease In Deferred Income Taxes	us-gaap/2024	Deferred tax expense/(benefit)	1
0001628280-25-020465	8	11	CF	0	H	Gains Losses On Investment And Foreign Exchange	0001628280-25-020465	Net realized and unrealized investment foreign exchange losses/(gains)	1
0001628280-25-020465	8	12	CF	0	H	Gain Loss On Sale Of Derivatives	us-gaap/2024	Net change from current period hedged transactions	1
0001628280-25-020465	8	13	CF	0	H	Unrealized Gainloss On Real Estate Fund In Net Investment Income	0001628280-25-020465	Unrealized (gain)/loss on real estate fund in net investment income	1
0001628280-25-020465	8	15	CF	0	H	Increase Decrease In Liability For Claims And Claims Adjustment Expense Reserve	us-gaap/2024	Reserve for losses and loss adjustment expenses	0
0001628280-25-020465	8	16	CF	0	H	Increase Decrease In Unearned Premiums	us-gaap/2024	Unearned premiums	0
0001628280-25-020465	8	17	CF	0	H	Increase Decrease In Unpaid Losses Recoverable From Reinsurers	0001628280-25-020465	Unpaid losses recoverable from reinsurers	0
0001628280-25-020465	8	18	CF	0	H	Increase Decrease In Prepaid Reinsurance Premiums	us-gaap/2024	Ceded unearned premiums	1
0001628280-25-020465	8	19	CF	0	H	Increase Decrease In Deferred Policy Acquisition Costs	us-gaap/2024	Deferred acquisition costs	1
0001628280-25-020465	8	20	CF	0	H	Increase Decrease In Reinsurance Payables	us-gaap/2024	Reinsurance premiums payable	0
0001628280-25-020465	8	21	CF	0	H	Increase Decrease In Premiums Receivable	us-gaap/2024	Underwriting premiums receivable	1
0001628280-25-020465	8	22	CF	0	H	Increase Decrease In Accrued Income Taxes Payable	us-gaap/2024	Income tax payable and refundable	0
0001628280-25-020465	8	23	CF	0	H	Increase Decrease In Accrued Liabilities	us-gaap/2024	Accrued expenses and other payables	0
0001628280-25-020465	8	24	CF	0	H	Increase Decrease In Derivative Instruments	0001628280-25-020465	Derivative assets and derivative liabilities	0
0001628280-25-020465	8	25	CF	0	H	Operating Lease Payments	us-gaap/2024	Operating lease liabilities	1
0001628280-25-020465	8	26	CF	0	H	Increase Decrease In Other Operating Assets	us-gaap/2024	Other (1)	1
0001628280-25-020465	8	27	CF	0	H	Net Cash Provided By Used In Operating Activities	us-gaap/2024	Net cash provided by/(used in) operating activities	0
0001628280-25-020465	8	29	CF	0	H	Payments To Acquire Available For Sale Securities Debt	us-gaap/2024	(Purchases) of fixed income securities Available for sale	1
0001628280-25-020465	8	30	CF	0	H	Payments To Acquire Trading Securities Heldforinvestment	us-gaap/2024	(Purchases) of fixed income securities Trading	1
0001628280-25-020465	8	31	CF	0	H	Proceeds From Sale Of Available For Sale Securities Debt	us-gaap/2024	Proceeds from sales and maturities of fixed income securities Available for sale	0
0001628280-25-020465	8	32	CF	0	H	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities	us-gaap/2024	Proceeds from sales and maturities of fixed income securities Trading	0
0001628280-25-020465	8	33	CF	0	H	Purchases Of Proceeds From Catastrophe Bonds	0001628280-25-020465	Net proceeds from catastrophe bonds Trading	1
0001628280-25-020465	8	34	CF	0	H	Paymentsfor Availableforsale Securities Shortterm	0001628280-25-020465	(Purchases) of short-term investments Available for sale	1
0001628280-25-020465	8	35	CF	0	H	Proceedsfrom Availableforsale Securities Shortterm	0001628280-25-020465	Proceeds from sale of short-term investments Available for sale	0
0001628280-25-020465	8	36	CF	0	H	Payments To Acquire Short Term Investments	us-gaap/2024	(Purchases) of short-term investments Trading	1
0001628280-25-020465	8	37	CF	0	H	Proceeds From Sale Of Short Term Investments	us-gaap/2024	Proceeds from sale of short-term investments Trading	0
0001628280-25-020465	8	38	CF	0	H	Purchases Of Privately Held Investments Available For Sale	0001628280-25-020465	(Purchases) of privately-held investments - Available for sale	1
0001628280-25-020465	8	39	CF	0	H	Payments To Acquire Privately Held Investments Trading	0001628280-25-020465	(Purchases) of privately-held investments Trading	1
0001628280-25-020465	8	40	CF	0	H	Proceedsfrom Saleof Privatelyheld Investments	0001628280-25-020465	Proceeds from sale of privately-held investments Trading	0
0001628280-25-020465	8	41	CF	0	H	Net Changein Receivablefor Securities Soldor Payablefor Securities Purchased	0001628280-25-020465	Net change in receivable/(payable) for securities sold/(purchased)	0
0001628280-25-020465	8	42	CF	0	H	Payments For Proceeds From Other Investing Activities	us-gaap/2024	(Purchases) of other investments	1
0001628280-25-020465	8	43	CF	0	H	Paymentsfor Proceedsfrom Investing Activities Netof Cash	0001628280-25-020465	Net proceeds from sales of other investments	1
0001628280-25-020465	8	44	CF	0	H	Payments For Proceeds From Productive Assets	us-gaap/2024	Net (purchases)/sales of fixed assets	0
0001628280-25-020465	8	45	CF	0	H	Payments To Acquire Equity Method Investments	us-gaap/2024	Net (purchases) of investments, equity method	1
0001628280-25-020465	8	46	CF	0	H	Net Cash Provided By Used In Investing Activities	us-gaap/2024	Net cash (used in) investing activities	0
0001628280-25-020465	8	48	CF	0	H	Repayments Of Short Term Debt	us-gaap/2024	Repayments of Short-Term Debt	1
0001628280-25-020465	8	49	CF	0	H	Proceeds From Term Loan Facility	0001628280-25-020465	Proceeds from term loan facility	0
0001628280-25-020465	8	50	CF	0	H	Payments For Repurchase Of Preferred Stock And Preference Stock	us-gaap/2024	Redemption of preference shares (1)	1
0001628280-25-020465	8	51	CF	0	H	Proceeds From Issuance Of Preferred Stock And Preference Stock	us-gaap/2024	Preference share issuance	0
0001628280-25-020465	8	52	CF	0	H	Payments Of Dividends Common Stock	us-gaap/2024	Payments of Ordinary Dividends, Common Stock	0
0001628280-25-020465	8	53	CF	0	H	Payments Of Dividends Preferred Stock And Preference Stock	us-gaap/2024	Dividends paid on preference shares	1
0001628280-25-020465	8	54	CF	0	H	Net Cash Provided By Used In Financing Activities	us-gaap/2024	Net cash (used in) financing activities	0
0001628280-25-020465	8	55	CF	0	H	Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents	us-gaap/2024	Effect of exchange rate movements on cash and cash equivalents	0
0001628280-25-020465	8	56	CF	0	H	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect	us-gaap/2024	(Decrease)/Increase in cash and cash equivalents	0
0001628280-25-020465	8	57	CF	0	H	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations	us-gaap/2024	Cash and cash equivalents at beginning of period	0
0001628280-25-020465	8	58	CF	0	H	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations	us-gaap/2024	Cash and cash equivalents at end of period (2)	0
0001628280-25-020465	8	60	CF	0	H	Income Taxes Paid Net	us-gaap/2024	Income taxes paid	0
0001628280-25-020465	8	61	CF	0	H	Interest Paid	us-gaap/2024	Interest paid on long-term debt	0
0001628280-25-020465	9	9	CF	1	H	Cash And Cash Equivalents Includes Restricted Cash	0001628280-25-020465	Restricted cash	0
0001628280-25-020465	9	10	CF	1	H	Preferred Stock Shares Issued	us-gaap/2024	Preferred Stock, Shares Issued	0
0001628280-25-020465	9	11	CF	1	H	Preferred Stock Dividend Rate Percentage	us-gaap/2024	Preferred Stock, Dividend Rate, Percentage	0
0001628280-25-020465	9	12	CF	1	H	Preferred Stock Liquidation Preference Value	us-gaap/2024	Preference shares liquidation preference, value	0

Description

Field Name	Field Description
adsh	Accession Number. The 20-character string formed from the 18-digit number assigned by the SEC to each EDGAR submission.
report	Represents the report grouping. This field corresponds to the statement (stmt) field, which indicates the type of statement. The numeric value refers to the “R file” as posted on the EDGAR Web site.
line	Represents the tag’s presentation line order for a given report. Together with the statement and report field, presentation location, order and grouping can be derived.
stmt	The financial statement location to which the value of the “report” field pertains.
inpth	Value was presented “parenthetically” instead of in columns within the financial statements. For example: Receivables (net of allowance for bad debts of $200 in 2012) $700.
rfile	The type of interactive data file rendered on the EDGAR web site, H = .htm file, X = .xml file.
tag	The tag chosen by the filer for this line item.
version	The taxonomy identifier if the tag is a standard tag, otherwise adsh.
plabel	The text presented on the line item, also known as a “preferred” label.
negating	Flag to indicate whether the plabel is negating.