v3.26.3
Derivatives - Credit Risk Assumed through Credit Derivatives (Details) - USD ($)
$ in Millions
 9 Months Ended 12 Months Ended
Sep. 30, 2026
Dec. 31, 2025
Credit Derivatives [Line Items]    
Derivative, Notional Amount $ 10,437 $ 6,269
Fair Value 7 0
Credit derivatives    
Credit Derivatives [Line Items]    
Derivative, Notional Amount 485 493
Fair Value 17 27
Derivative, Nominal Value, Amount Offset Against Collateral, Net 485 493
Offsetting Fair Value (17) (27)
Standard & Poor's, AAA Rating [Member] | Basket credit default swaps | Credit derivatives | Investment grade risk exposure    
Credit Derivatives [Line Items]    
Derivative, Notional Amount 100 100
Fair Value $ 0 $ 1
Weighted Average Years to Maturity 2 years 3 years
Derivative, Nominal Value, Amount Offset Against Collateral, Net $ 100 $ 100
Offsetting Fair Value 0 (1)
Standard & Poor's, BB- Rating | Basket credit default swaps | Credit derivatives | Below investment grade risk exposure    
Credit Derivatives [Line Items]    
Derivative, Notional Amount 384  
Fair Value $ 17  
Weighted Average Years to Maturity 2 years  
Derivative, Nominal Value, Amount Offset Against Collateral, Net $ 384  
Offsetting Fair Value (17)  
Standard & Poor's, B- Rating | Basket credit default swaps | Credit derivatives | Below investment grade risk exposure    
Credit Derivatives [Line Items]    
Derivative, Notional Amount 1 1
Fair Value $ 0 $ (1)
Average Term of Credit Risk Derivatives Less than 1 Year Less than 1 year Less than 1 year
Derivative, Nominal Value, Amount Offset Against Collateral, Net $ 1 $ 1
Offsetting Fair Value $ 0 1
Standard & Poor's, B+ Rating | Basket credit default swaps | Credit derivatives | Below investment grade risk exposure    
Credit Derivatives [Line Items]    
Derivative, Notional Amount   392
Fair Value   $ 27
Weighted Average Years to Maturity   2 years
Derivative, Nominal Value, Amount Offset Against Collateral, Net   $ 392
Offsetting Fair Value   $ (27)