v3.26.1
Derivatives (Credit Derivatives) (Details) - USD ($)
$ in Millions
 6 Months Ended 12 Months Ended
Jun. 30, 2026
Dec. 31, 2025
Credit Derivatives [Line Items]    
Estimated Fair Value of Credit Default Swaps $ 16 $ 11
Maximum Amount of Future Payments under Credit Default Swaps $ 797 $ 468
Weighted Average Years to Maturity (2) 4 years 2 months 12 days 4 years 1 month 6 days
Credit default swaps | Aaa/Aa/A    
Credit Derivatives [Line Items]    
Estimated Fair Value of Credit Default Swaps $ 1 $ 2
Maximum Amount of Future Payments under Credit Default Swaps $ 94 $ 94
Weighted Average Years to Maturity (2) 1 year 3 months 18 days 1 year 9 months 18 days
Credit default swaps | Baa    
Credit Derivatives [Line Items]    
Estimated Fair Value of Credit Default Swaps $ 15 $ 8
Maximum Amount of Future Payments under Credit Default Swaps $ 680 $ 350
Weighted Average Years to Maturity (2) 4 years 8 months 12 days 5 years
Credit default swaps | Ba    
Credit Derivatives [Line Items]    
Estimated Fair Value of Credit Default Swaps $ 0 $ 1
Maximum Amount of Future Payments under Credit Default Swaps $ 23 $ 24
Weighted Average Years to Maturity (2) 6 months 1 year