v3.25.2
Investments (Securities in a gross unrealized loss position) (Details) - USD ($)
$ in Millions
Jun. 30, 2025
Dec. 31, 2024
Debt Securities, Available-for-sale [Line Items]    
Estimated Fair Value, Less than 12 months $ 6,927 $ 9,019
Gross Unrealized Losses, Less than 12 Months 243 267
Estimated Fair Value, 12 Months or Longer 17,110 18,319
Gross Unrealized Losses, 12 Months or Longer 2,496 2,773
Estimated Fair Value, Total 24,037 27,338
Gross Unrealized Losses, Total 2,739 3,040
Corporate and other bonds    
Debt Securities, Available-for-sale [Line Items]    
Estimated Fair Value, Less than 12 months 4,252 5,846
Gross Unrealized Losses, Less than 12 Months 135 165
Estimated Fair Value, 12 Months or Longer 9,515 10,388
Gross Unrealized Losses, 12 Months or Longer 934 1,140
Estimated Fair Value, Total 13,767 16,234
Gross Unrealized Losses, Total 1,069 1,305
States, municipalities and political subdivisions    
Debt Securities, Available-for-sale [Line Items]    
Estimated Fair Value, Less than 12 months 1,424 1,247
Gross Unrealized Losses, Less than 12 Months 74 52
Estimated Fair Value, 12 Months or Longer 2,938 2,967
Gross Unrealized Losses, 12 Months or Longer 818 783
Estimated Fair Value, Total 4,362 4,214
Gross Unrealized Losses, Total 892 835
Residential mortgage-backed    
Debt Securities, Available-for-sale [Line Items]    
Estimated Fair Value, Less than 12 months 372 849
Gross Unrealized Losses, Less than 12 Months 9 22
Estimated Fair Value, 12 Months or Longer 1,966 2,010
Gross Unrealized Losses, 12 Months or Longer 418 466
Estimated Fair Value, Total 2,338 2,859
Gross Unrealized Losses, Total 427 488
Commercial mortgage-backed    
Debt Securities, Available-for-sale [Line Items]    
Estimated Fair Value, Less than 12 months 99 230
Gross Unrealized Losses, Less than 12 Months 1 3
Estimated Fair Value, 12 Months or Longer 959 988
Gross Unrealized Losses, 12 Months or Longer 106 139
Estimated Fair Value, Total 1,058 1,218
Gross Unrealized Losses, Total 107 142
Other asset-backed    
Debt Securities, Available-for-sale [Line Items]    
Estimated Fair Value, Less than 12 months 580 680
Gross Unrealized Losses, Less than 12 Months 18 21
Estimated Fair Value, 12 Months or Longer 1,419 1,557
Gross Unrealized Losses, 12 Months or Longer 195 218
Estimated Fair Value, Total 1,999 2,237
Gross Unrealized Losses, Total 213 239
Asset-backed    
Debt Securities, Available-for-sale [Line Items]    
Estimated Fair Value, Less than 12 months 1,051 1,759
Gross Unrealized Losses, Less than 12 Months 28 46
Estimated Fair Value, 12 Months or Longer 4,344 4,555
Gross Unrealized Losses, 12 Months or Longer 719 823
Estimated Fair Value, Total 5,395 6,314
Gross Unrealized Losses, Total 747 869
U.S. Treasury and obligations of government-sponsored enterprises    
Debt Securities, Available-for-sale [Line Items]    
Estimated Fair Value, Less than 12 months 55 49
Gross Unrealized Losses, Less than 12 Months 3 1
Estimated Fair Value, 12 Months or Longer 19 41
Gross Unrealized Losses, 12 Months or Longer 2 0
Estimated Fair Value, Total 74 90
Gross Unrealized Losses, Total 5 1
Foreign government    
Debt Securities, Available-for-sale [Line Items]    
Estimated Fair Value, Less than 12 months 145 118
Gross Unrealized Losses, Less than 12 Months 3 3
Estimated Fair Value, 12 Months or Longer 294 368
Gross Unrealized Losses, 12 Months or Longer 23 27
Estimated Fair Value, Total 439 486
Gross Unrealized Losses, Total $ 26 $ 30