Derivatives and Hedge Accounting - Derivatives not Designated as Hedging Instruments (Details) - Derivatives not designated as hedging instruments - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total	$ 16	$ (75)
Net realized gains (losses) - Excluding Fortitude Re Funds Withheld Assets
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total	$ 2	$ (28)
Derivative, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Realized Investment Gains (Losses)	Realized Investment Gains (Losses)
Net Realized Gains (Losses) On Fortitude Re funds Withheld Assets
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total	$ 14	$ (47)
Derivative, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Realized Investment Gains (Losses)	Realized Investment Gains (Losses)
Interest rate contracts
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total	$ 1	$ (1)
Foreign exchange contracts
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total	5	(33)
Embedded derivatives
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total	$ 10	$ (41)