v3.26.1
Derivative Instruments (Exposure from Credit Derivatives by Rating of the Underlying Credits) (Details) - USD ($)
$ in Millions
 3 Months Ended 12 Months Ended
Mar. 31, 2026
Dec. 31, 2025
Credit Derivatives [Line Items]    
Credit Derivative Current Fair Value [1] $ 2 $ (7)
Maximum Potential Future Exposure on Credit Risk Derivatives [1],[2] $ 8,073 $ 6,573
Derivative Average Remaining Maturity [1],[3] 6 years 1 month 6 days 6 years
Standard Poors AAA To A Minus Ratings [Member] | Single Name Credit Default Swaps [Member]    
Credit Derivatives [Line Items]    
Credit Derivative Current Fair Value [1] $ (13) $ (7)
Maximum Potential Future Exposure on Credit Risk Derivatives [1],[2] $ 490 $ 490
Derivative Average Remaining Maturity [1],[3] 13 years 10 months 24 days 14 years 2 months 12 days
Standard Poors BBB Rating [Member] | Single Name Credit Default Swaps [Member]    
Credit Derivatives [Line Items]    
Credit Derivative Current Fair Value [1] $ 2 $ 2
Maximum Potential Future Exposure on Credit Risk Derivatives [1],[2] $ 170 $ 170
Derivative Average Remaining Maturity [1],[3] 1 year 9 months 18 days 2 years 1 month 6 days
Standard Poors BBB Rating [Member] | Credit Default Swaps Referencing Indices [Member]    
Credit Derivatives [Line Items]    
Credit Derivative Current Fair Value [1] $ 13 $ (2)
Maximum Potential Future Exposure on Credit Risk Derivatives [1],[2] $ 7,403 $ 5,903
Derivative Average Remaining Maturity [1],[3] 5 years 8 months 12 days 5 years 6 months
Standard Poors BBB Rating [Member] | Credit Default Subtotal [Member]    
Credit Derivatives [Line Items]    
Credit Derivative Current Fair Value [1] $ 15 $ 0
Maximum Potential Future Exposure on Credit Risk Derivatives [1],[2] $ 7,573 $ 6,073
Derivative Average Remaining Maturity [1],[3] 5 years 7 months 6 days 5 years 4 months 24 days
Standard & Poor's, BB Rating [Member]    
Credit Derivatives [Line Items]    
Derivative Average Remaining Maturity [1],[3] 2 months 12 days 6 months
Standard & Poor's, BB Rating [Member] | Single Name Credit Default Swaps [Member]    
Credit Derivatives [Line Items]    
Credit Derivative Current Fair Value [1] $ 0 $ 0
Maximum Potential Future Exposure on Credit Risk Derivatives [1],[2] $ 5 $ 5
Standard & Poor's, B Rating    
Credit Derivatives [Line Items]    
Derivative Average Remaining Maturity [1],[3] 2 months 12 days 6 months
Standard & Poor's, B Rating | Single Name Credit Default Swaps [Member]    
Credit Derivatives [Line Items]    
Credit Derivative Current Fair Value [1] $ 0 $ 0
Maximum Potential Future Exposure on Credit Risk Derivatives [1],[2] $ 5 $ 5
[1] ating agency designations are based on ratings from Standard and Poor’s (“S&P”) when available. Other credited rating agencies or internal ratings may be used when S&P ratings are not available.
[2] Assumes the value of the referenced credit obligations is zero.
[3] The weighted average years to maturity of the credit default swaps is calculated based on weighted average notional amounts.