Reinsurance - Summary of the Composition of Pool of Assets (Details) - USD ($) $ in Millions		6 Months Ended
		Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Effects of Reinsurance [Line Items]
Bonds available for sale	[1]	$ 62,333		$ 65,242
Fixed maturity securities - fair value option	[1]	766		663
Short-term investments	[1]	12,563		12,865
Other assets	[1]	4,717		5,425
Total assets		167,890		539,306
Carrying Value
Effects of Reinsurance [Line Items]
Short-term investments		4,426		3,502
Other assets		18		32
Commercial mortgage loans
Effects of Reinsurance [Line Items]
Loans		3,728		3,836
Fortitude Holdings
Effects of Reinsurance [Line Items]
Change in net unrealized gains (losses), gross		(53)	$ 21
Change in net unrealized gains (losses), net of tax		(42)	$ 16
Derivative asset, Fair value of collateral		3		1
Derivative liability, Fair value of collateral		27		28
Fortitude Holdings | Carrying Value
Effects of Reinsurance [Line Items]
Bonds available for sale		1,997		2,180
Fixed maturity securities - fair value option		761		655
Short-term investments		18		46
Funds withheld investment assets		3,250		3,424
Derivative assets, net		1		0
Other assets		126		118
Total assets		3,377		3,542
Fortitude Holdings | Estimated Fair Value
Effects of Reinsurance [Line Items]
Bonds available for sale		1,997		2,180
Fixed maturity securities - fair value option		761		655
Short-term investments		18		46
Funds withheld investment assets		3,237		3,409
Derivative assets, net		1		0
Other assets, fair value		126		118
Total		3,364		3,527
Fortitude Holdings | Commercial mortgage loans | Carrying Value
Effects of Reinsurance [Line Items]
Loans		474		543
Fortitude Holdings | Commercial mortgage loans | Estimated Fair Value
Effects of Reinsurance [Line Items]
Loans, fair value		$ 461		$ 528

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