v3.26.1
Investments (Securities Lending Remaining Tenor) (Details) - USD ($)
$ in Millions
Mar. 31, 2026
Dec. 31, 2025
Securities Financing Transaction [Line Items]    
Cash collateral received from counterparties $ 3,215 $ 3,225
Remaining Tenor of Securities Lending Agreements: Open    
Securities Financing Transaction [Line Items]    
Cash collateral received from counterparties 322 480
Remaining Tenor of Securities Lending Agreements: 1 Month or Less    
Securities Financing Transaction [Line Items]    
Cash collateral received from counterparties 967 968
Remaining Tenor of Securities Lending Agreements: 1 to 6 Months    
Securities Financing Transaction [Line Items]    
Cash collateral received from counterparties 1,926 1,777
U.S. government and agency    
Securities Financing Transaction [Line Items]    
Cash collateral received from counterparties 2,851 2,857
U.S. government and agency | Remaining Tenor of Securities Lending Agreements: Open    
Securities Financing Transaction [Line Items]    
Cash collateral received from counterparties 321 417
U.S. government and agency | Remaining Tenor of Securities Lending Agreements: 1 Month or Less    
Securities Financing Transaction [Line Items]    
Cash collateral received from counterparties 927 663
U.S. government and agency | Remaining Tenor of Securities Lending Agreements: 1 to 6 Months    
Securities Financing Transaction [Line Items]    
Cash collateral received from counterparties 1,603 1,777
U.S. corporate    
Securities Financing Transaction [Line Items]    
Cash collateral received from counterparties 310 304
U.S. corporate | Remaining Tenor of Securities Lending Agreements: Open    
Securities Financing Transaction [Line Items]    
Cash collateral received from counterparties 0 48
U.S. corporate | Remaining Tenor of Securities Lending Agreements: 1 Month or Less    
Securities Financing Transaction [Line Items]    
Cash collateral received from counterparties 36 256
U.S. corporate | Remaining Tenor of Securities Lending Agreements: 1 to 6 Months    
Securities Financing Transaction [Line Items]    
Cash collateral received from counterparties 274 0
Foreign corporate    
Securities Financing Transaction [Line Items]    
Cash collateral received from counterparties 46 62
Foreign corporate | Remaining Tenor of Securities Lending Agreements: Open    
Securities Financing Transaction [Line Items]    
Cash collateral received from counterparties 0 15
Foreign corporate | Remaining Tenor of Securities Lending Agreements: 1 Month or Less    
Securities Financing Transaction [Line Items]    
Cash collateral received from counterparties 2 47
Foreign corporate | Remaining Tenor of Securities Lending Agreements: 1 to 6 Months    
Securities Financing Transaction [Line Items]    
Cash collateral received from counterparties 44 0
Foreign government    
Securities Financing Transaction [Line Items]    
Cash collateral received from counterparties 8 2
Foreign government | Remaining Tenor of Securities Lending Agreements: Open    
Securities Financing Transaction [Line Items]    
Cash collateral received from counterparties 1 0
Foreign government | Remaining Tenor of Securities Lending Agreements: 1 Month or Less    
Securities Financing Transaction [Line Items]    
Cash collateral received from counterparties 2 2
Foreign government | Remaining Tenor of Securities Lending Agreements: 1 to 6 Months    
Securities Financing Transaction [Line Items]    
Cash collateral received from counterparties $ 5 $ 0