Investments - Schedule of Securities Pledged As Collateral For Repurchase Agreements (Details) - USD ($) $ in Millions	Jun. 30, 2026	Dec. 31, 2025
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 241,650	$ 228,168
Fair Value	229,841	218,644
Asset Pledged as Collateral \| Securities Sold under Agreements to Repurchase
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	3,797	6,528
Fair Value	3,417	6,225
U.S. government and agencies \| Asset Pledged as Collateral \| Securities Sold under Agreements to Repurchase
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	0	2,780
Fair Value	0	2,787
Foreign governments \| Asset Pledged as Collateral \| Securities Sold under Agreements to Repurchase
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	259	241
Fair Value	190	185
Corporate \| Asset Pledged as Collateral \| Securities Sold under Agreements to Repurchase
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	2,102	2,022
Fair Value	1,813	1,785
CLO \| Asset Pledged as Collateral \| Securities Sold under Agreements to Repurchase
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	594	611
Fair Value	590	608
ABS \| Asset Pledged as Collateral \| Securities Sold under Agreements to Repurchase
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	524	584
Fair Value	505	568
CMBS \| Asset Pledged as Collateral \| Securities Sold under Agreements to Repurchase
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	231	197
Fair Value	231	198
RMBS \| Asset Pledged as Collateral \| Securities Sold under Agreements to Repurchase
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	87	93
Fair Value	$ 88	$ 94