Investments - Components of Net Realized Gains and Losses (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2025	Mar. 31, 2024
Components of net realized capital gains (losses)
Sales of fixed maturity securities	$ (262)	$ (101)
Net realized gains (losses)	(103)	(87)
Excluding Fortitude Re Funds Withheld Assets
Components of net realized capital gains (losses)
Net realized gains (losses)	(60)	(59)
Fortitude Re Funds Withheld Assets
Components of net realized capital gains (losses)
Net realized gains (losses)	(43)	(28)
Excluding modified coinsurance and funds withheld embedded derivative
Components of net realized capital gains (losses)
Sales of fixed maturity securities	(262)	(101)
Change in allowance for credit losses on fixed maturity securities	8	(1)
Foreign exchange transactions	226	56
All other derivatives and hedge accounting	(34)	(46)
Sales of alternative investments	0	9
Other	(9)	15
Net realized gains (losses)	(62)	(78)
Excluding modified coinsurance and funds withheld embedded derivative \| Loans Receivable
Components of net realized capital gains (losses)
Change in allowance for credit losses on loans	9	(10)
Excluding modified coinsurance and funds withheld embedded derivative \| Excluding Fortitude Re Funds Withheld Assets
Components of net realized capital gains (losses)
Sales of fixed maturity securities	(255)	(86)
Change in allowance for credit losses on fixed maturity securities	8	(1)
Foreign exchange transactions	220	59
All other derivatives and hedge accounting	(28)	(48)
Sales of alternative investments	0	10
Other	(10)	15
Net realized gains (losses)	(60)	(59)
Excluding modified coinsurance and funds withheld embedded derivative \| Excluding Fortitude Re Funds Withheld Assets \| Loans Receivable
Components of net realized capital gains (losses)
Change in allowance for credit losses on loans	5	(8)
Excluding modified coinsurance and funds withheld embedded derivative \| Fortitude Re Funds Withheld Assets
Components of net realized capital gains (losses)
Sales of fixed maturity securities	(7)	(15)
Change in allowance for credit losses on fixed maturity securities	0	0
Foreign exchange transactions	6	(3)
All other derivatives and hedge accounting	(6)	2
Sales of alternative investments	0	(1)
Other	1	0
Net realized gains (losses)	(2)	(19)
Excluding modified coinsurance and funds withheld embedded derivative \| Fortitude Re Funds Withheld Assets \| Loans Receivable
Components of net realized capital gains (losses)
Change in allowance for credit losses on loans	4	(2)
Fortitude Re funds withheld embedded derivative
Components of net realized capital gains (losses)
Net realized gains (losses)	(41)	(9)
Fortitude Re funds withheld embedded derivative \| Excluding Fortitude Re Funds Withheld Assets
Components of net realized capital gains (losses)
Net realized gains (losses)	0	0
Fortitude Re funds withheld embedded derivative \| Fortitude Re Funds Withheld Assets
Components of net realized capital gains (losses)
Net realized gains (losses)	$ (41)	$ (9)

Gain Loss On Sale Of Alternative Investments

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- Definition

Represents other investment charges not specified in the taxonomy.

+ References

No definition available.

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- Definition

Amount, excluding accrued interest, of increase (decrease) in allowance for credit loss of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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-Name Accounting Standards Codification
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-Paragraph 9
-Publisher FASB
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- Definition

Amount of realized gain (loss) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount, excluding accrued interest, of credit loss expense (reversal of expense) on financing receivable. Excludes net investment in lease.

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- Definition

Amount, before tax, of realized and unrealized gain (loss) from foreign currency transaction.

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Amount of realized and unrealized gain (loss) on investment.

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- Definition

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.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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