Reinsurance - Summary of the Composition of Pool of Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024
Effects of Reinsurance [Line Items]
Fixed maturity securities - available for sale	$ 71,032	$ 64,006
Fixed maturity securities - fair value option	741	745
Short-term investments	11,141	14,462
Other	4,773	4,735
Total assets	161,254	161,322
Carrying Value
Effects of Reinsurance [Line Items]
Short-term investments	5,232	4,673
Other	16	15
Commercial mortgage loans
Effects of Reinsurance [Line Items]
Loans, carrying value	2,495	3,305
Fortitude Holdings
Effects of Reinsurance [Line Items]
Change in net unrealized gains (losses), gross	85	(35)
Change in net unrealized gains (losses), net of tax	67	(28)
Derivative asset, Fair value of collateral	1	9
Derivative liability, Fair value of collateral	31	2
Fortitude Holdings | Carrying Value
Effects of Reinsurance [Line Items]
Fixed maturity securities - available for sale	1,780	1,918
Fixed maturity securities - fair value option	734	721
Short-term investments	43	15
Funds withheld investment assets	2,916	3,104
Derivative assets, net	0	1
Other	137	115
Total assets	3,053	3,220
Fortitude Holdings | Estimated Fair Value
Effects of Reinsurance [Line Items]
Fixed maturity securities - available for sale	1,780	1,918
Fixed maturity securities - fair value option	734	721
Short-term investments	43	15
Funds withheld investment assets	2,901	3,091
Derivative assets, net	0	1
Other, fair value	137	115
Total	3,038	3,207
Fortitude Holdings | Commercial mortgage loans | Carrying Value
Effects of Reinsurance [Line Items]
Loans, carrying value	359	450
Fortitude Holdings | Commercial mortgage loans | Estimated Fair Value
Effects of Reinsurance [Line Items]
Loans, fair value	$ 344	$ 437