Reinsurance - Summary of the Composition of Pool of Assets (Details) - USD ($) $ in Millions		9 Months Ended
		Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Effects of Reinsurance [Line Items]
Bonds available for sale	[1]	$ 65,980		$ 65,242
Fixed maturity securities - fair value option		763		663
Short-term investments	[1]	11,848		12,865
Other assets	[1]	4,553		5,425
Total assets		169,449		539,306
Carrying Value
Effects of Reinsurance [Line Items]
Short-term investments		3,026		3,502
Other assets		15		32
Commercial mortgage loans
Effects of Reinsurance [Line Items]
Loans		3,696		3,836
Fortitude Holdings
Effects of Reinsurance [Line Items]
Change in net unrealized gains (losses), gross		31	$ (60)
Change in net unrealized gains (losses), net of tax		25	$ (47)
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		2,148		2,180
Fixed maturity securities - fair value option		749		655
Short-term investments		21		46
Funds withheld investment assets		3,393		3,424
Derivative assets, net		0		0
Other assets		103		118
Total assets		3,496		3,542
Fortitude Holdings | Estimated Fair Value
Effects of Reinsurance [Line Items]
Bonds available for sale		2,148		2,180
Fixed maturity securities - fair value option		749		655
Short-term investments		21		46
Funds withheld investment assets		3,374		3,409
Derivative assets, net		0		0
Other assets, fair value		103		118
Total		3,477		3,527
Fortitude Holdings | Commercial mortgage loans | Carrying Value
Effects of Reinsurance [Line Items]
Loans		475		543
Fortitude Holdings | Commercial mortgage loans | Estimated Fair Value
Effects of Reinsurance [Line Items]
Loans, fair value		$ 456		$ 528

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