v3.26.3
Derivative Instruments (Exposure from Credit Derivatives by Rating of the Underlying Credits) (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Mar. 31, 2026
Sep. 30, 2026
Dec. 31, 2025
Credit Derivatives [Line Items]      
Credit Derivative Current Fair Value [1]   $ (28) $ (7)
Maximum Potential Future Exposure on Credit Risk Derivatives [1],[2]   $ 7,999 6,573
Derivative Average Remaining Maturity [1],[3] 6 years 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]   $ (25) (7)
Maximum Potential Future Exposure on Credit Risk Derivatives [1],[2]   $ 430 490
Derivative Average Remaining Maturity [1],[3] 14 years 2 months 12 days 15 years 3 months 18 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]   $ 165 170
Derivative Average Remaining Maturity [1],[3] 2 years 1 month 6 days 1 year 4 months 24 days  
Standard Poors BBB Rating [Member] | Credit Default Swaps Referencing Indices [Member]      
Credit Derivatives [Line Items]      
Credit Derivative Current Fair Value [1]   $ (5) (2)
Maximum Potential Future Exposure on Credit Risk Derivatives [1],[2]   $ 7,404 5,903
Derivative Average Remaining Maturity [1],[3] 5 years 6 months 5 years 7 months 6 days  
Standard Poors BBB Rating [Member] | Credit Default Subtotal [Member]      
Credit Derivatives [Line Items]      
Credit Derivative Current Fair Value [1]   $ (3) 0
Maximum Potential Future Exposure on Credit Risk Derivatives [1],[2]   $ 7,569 6,073
Derivative Average Remaining Maturity [1],[3] 5 years 4 months 24 days 5 years 6 months  
Standard & Poor's, BB Rating [Member]      
Credit Derivatives [Line Items]      
Derivative Average Remaining Maturity [1],[2] 6 months 0 years  
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]   $ 0 5
Standard & Poor's, B Rating      
Credit Derivatives [Line Items]      
Derivative Average Remaining Maturity [3] 6 months 0 years  
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 [2]   $ 0 $ 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.