v3.26.1
Fair Value (Table of reconciliation for assets and liabilities measured at fair value on a recurring basis using significant unobservable inputs) (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Balance, Beginning, Assets $ 2,539 $ 2,216
Reported in Net investment gains (losses) $ (6) $ 2
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] Net investment losses Net investment losses
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Asset, Gain (Loss), Statement of Other Comprehensive Income or Comprehensive Income [Extensible Enumeration] Other comprehensive (loss) income Other comprehensive (loss) income
Reported in Other comprehensive income (loss) $ (41) $ 24
Total realized and unrealized investment gains (losses) (43) 29
Purchases 103 82
Sales 0 0
Settlements (25) (41)
Transfers into Level 3 0 15
Transfers out of Level 3 (49) 0
Balance, Ending, Assets 2,525 2,301
Unrealized gains (losses) on Level 3 assets and liabilities recognized in Net income (loss) in the period (1) (1)
Unrealized gains (losses) on Level 3 assets and liabilities recognized in Other comprehensive income (loss) in the period (41) 24
Corporate and other bonds    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Balance, Beginning, Assets 1,483 1,278
Reported in Net investment gains (losses) (3) 0
Reported in Other comprehensive income (loss) (24) 21
Total realized and unrealized investment gains (losses) (27) 21
Purchases 63 55
Sales 0 0
Settlements (5) (18)
Transfers into Level 3 0 15
Transfers out of Level 3 0 0
Balance, Ending, Assets 1,514 1,351
Unrealized gains (losses) on Level 3 assets and liabilities recognized in Net income (loss) in the period 0 0
Unrealized gains (losses) on Level 3 assets and liabilities recognized in Other comprehensive income (loss) in the period (24) 21
States, municipalities and political subdivisions    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Balance, Beginning, Assets 45 42
Reported in Net investment gains (losses) 0 0
Reported in Other comprehensive income (loss) (1) 2
Total realized and unrealized investment gains (losses) (1) 2
Purchases 0 0
Sales 0 0
Settlements 0 0
Transfers into Level 3 0 0
Transfers out of Level 3 0 0
Balance, Ending, Assets 44 44
Unrealized gains (losses) on Level 3 assets and liabilities recognized in Net income (loss) in the period 0 0
Unrealized gains (losses) on Level 3 assets and liabilities recognized in Other comprehensive income (loss) in the period (1) 2
Asset-backed    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Balance, Beginning, Assets 998 876
Reported in Net investment gains (losses) (3) 0
Reported in Other comprehensive income (loss) (16) 1
Total realized and unrealized investment gains (losses) (14) 5
Purchases 40 27
Sales 0 0
Settlements (20) (19)
Transfers into Level 3 0 0
Transfers out of Level 3 (49) 0
Balance, Ending, Assets 955 889
Unrealized gains (losses) on Level 3 assets and liabilities recognized in Net income (loss) in the period 0 0
Unrealized gains (losses) on Level 3 assets and liabilities recognized in Other comprehensive income (loss) in the period (16) 1
Equity securities    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Balance, Beginning, Assets 13 20
Reported in Net investment gains (losses) 0 2
Reported in Other comprehensive income (loss) 0 0
Total realized and unrealized investment gains (losses) (1) 1
Purchases 0 0
Sales 0 0
Settlements 0 (4)
Transfers into Level 3 0 0
Transfers out of Level 3 0 0
Balance, Ending, Assets 12 17
Unrealized gains (losses) on Level 3 assets and liabilities recognized in Net income (loss) in the period (1) (1)
Unrealized gains (losses) on Level 3 assets and liabilities recognized in Other comprehensive income (loss) in the period 0 0
Reported in Net investment income    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Reported in Net investment income 4 3
Reported in Net investment income | Corporate and other bonds    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Reported in Net investment income 0 0
Reported in Net investment income | States, municipalities and political subdivisions    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Reported in Net investment income 0 0
Reported in Net investment income | Asset-backed    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Reported in Net investment income 5 4
Reported in Net investment income | Equity securities    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Reported in Net investment income $ (1) $ (1)