Reinsurance - Summary of the Composition of Pool of Assets (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2024	Dec. 31, 2023
Effects of Reinsurance [Line Items]
Bonds available for sale	[1]	$ 64,006	$ 65,242
Fixed maturity securities - fair value option		745	663
Short-term investments	[1]	14,462	12,865
Other assets	[1]	4,735	5,425
Total assets		161,322	539,306
Carrying Value
Effects of Reinsurance [Line Items]
Short-term investments		4,673	3,502
Other assets		15	32
Commercial mortgage loans
Effects of Reinsurance [Line Items]
Loans		3,305	3,836
Fortitude Holdings
Effects of Reinsurance [Line Items]
Change in net unrealized gains (losses), gross		(35)	116
Change in net unrealized gains (losses), net of tax		(28)	92
Derivative asset, Fair value of collateral		9	1
Derivative liability, Fair value of collateral		2	28
Fortitude Holdings | Carrying Value
Effects of Reinsurance [Line Items]
Bonds available for sale		1,918	2,180
Fixed maturity securities - fair value option		721	655
Short-term investments		15	46
Funds withheld investment assets		3,104	3,424
Derivative assets, net		1	0
Other assets		115	118
Total assets		3,220	3,542
Fortitude Holdings | Estimated Fair Value
Effects of Reinsurance [Line Items]
Bonds available for sale		1,918	2,180
Fixed maturity securities - fair value option		721	655
Short-term investments		15	46
Funds withheld investment assets		3,091	3,409
Derivative assets, net		1	0
Other assets, fair value		115	118
Total		3,207	3,527
Fortitude Holdings | Commercial mortgage loans | Carrying Value
Effects of Reinsurance [Line Items]
Loans		450	543
Fortitude Holdings | Commercial mortgage loans | Estimated Fair Value
Effects of Reinsurance [Line Items]
Loans, fair value		$ 437	$ 528

[1] See Note 10 for details of balances associated with variable interest entities.