Investments - Repurchase Agreements (Details) - USD ($) $ in Millions	Jun. 30, 2026	Dec. 31, 2025
Schedule of Repurchase Agreements [Line Items]
Payables for repurchase agreements	$ 3,244	$ 6,043
Amortized Cost	3,797	6,528
Fair Value	3,417	6,225
Repurchase Agreements Net of Reverse Repurchase Agreements		907
Less than 30 days
Schedule of Repurchase Agreements [Line Items]
Payables for repurchase agreements	0	2,796
91 days to 1 year
Schedule of Repurchase Agreements [Line Items]
Payables for repurchase agreements	1,269	0
Greater than 1 year
Schedule of Repurchase Agreements [Line Items]
Payables for repurchase agreements	1,975	3,247
U.S. government and agencies
Schedule of Repurchase Agreements [Line Items]
Amortized Cost	0	2,780
Fair Value	0	2,787
Foreign governments
Schedule of Repurchase Agreements [Line Items]
Amortized Cost	259	241
Fair Value	190	185
Corporate
Schedule of Repurchase Agreements [Line Items]
Amortized Cost	2,102	2,022
Fair Value	1,813	1,785
Collateralized Loan Obligations
Schedule of Repurchase Agreements [Line Items]
Amortized Cost	594	611
Fair Value	590	608
ABS
Schedule of Repurchase Agreements [Line Items]
Amortized Cost	524	584
Fair Value	505	568
CMBS
Schedule of Repurchase Agreements [Line Items]
Amortized Cost	231	197
Fair Value	231	198
RMBS
Schedule of Repurchase Agreements [Line Items]
Amortized Cost	87	93
Fair Value	$ 88	$ 94