v3.25.2
Investments (Fair Value and Losses by Investment Category and Length of Time in a Loss Position) (Details) - USD ($)
$ in Millions
Jun. 30, 2025
Dec. 31, 2024
Debt Securities [Line Items]    
Less than Twelve Months, Fair Value $ 49,264 $ 66,934
Less than Twelve Months, Unrealized Losses 1,950 2,430
Twelve Months or More, Fair Value 140,903 142,997
Twelve Months or More, Unrealized Losses 32,180 32,158
Fair Value 190,167 209,931
Gross Unrealized Losses 34,130 34,588
U.S. Treasury securities and obligations of U.S. government authorities and agencies    
Debt Securities [Line Items]    
Less than Twelve Months, Fair Value 5,174 6,667
Less than Twelve Months, Unrealized Losses 213 334
Twelve Months or More, Fair Value 9,803 10,161
Twelve Months or More, Unrealized Losses 4,708 4,771
Fair Value 14,977 16,828
Gross Unrealized Losses 4,921 5,105
Obligations of U.S. states and their political subdivisions    
Debt Securities [Line Items]    
Less than Twelve Months, Fair Value 1,157 1,592
Less than Twelve Months, Unrealized Losses 69 53
Twelve Months or More, Fair Value 3,190 3,288
Twelve Months or More, Unrealized Losses 606 565
Fair Value 4,347 4,880
Gross Unrealized Losses 675 618
Foreign government securities    
Debt Securities [Line Items]    
Less than Twelve Months, Fair Value 8,501 8,280
Less than Twelve Months, Unrealized Losses 521 349
Twelve Months or More, Fair Value 22,882 20,780
Twelve Months or More, Unrealized Losses 10,565 7,532
Fair Value 31,383 29,060
Gross Unrealized Losses 11,086 7,881
U.S. public corporate securities    
Debt Securities [Line Items]    
Less than Twelve Months, Fair Value 20,645 25,420
Less than Twelve Months, Unrealized Losses 856 1,036
Twelve Months or More, Fair Value 47,399 48,152
Twelve Months or More, Unrealized Losses 9,658 10,485
Fair Value 68,044 73,572
Gross Unrealized Losses 10,514 11,521
U.S. private corporate securities    
Debt Securities [Line Items]    
Less than Twelve Months, Fair Value 4,879 7,581
Less than Twelve Months, Unrealized Losses 99 183
Twelve Months or More, Fair Value 24,281 24,846
Twelve Months or More, Unrealized Losses 2,204 2,743
Fair Value 29,160 32,427
Gross Unrealized Losses 2,303 2,926
Foreign public corporate securities    
Debt Securities [Line Items]    
Less than Twelve Months, Fair Value 4,519 5,751
Less than Twelve Months, Unrealized Losses 129 170
Twelve Months or More, Fair Value 7,894 8,084
Twelve Months or More, Unrealized Losses 1,173 1,246
Fair Value 12,413 13,835
Gross Unrealized Losses 1,302 1,416
Foreign private corporate securities    
Debt Securities [Line Items]    
Less than Twelve Months, Fair Value 1,368 8,702
Less than Twelve Months, Unrealized Losses 24 282
Twelve Months or More, Fair Value 17,248 18,862
Twelve Months or More, Unrealized Losses 2,648 4,010
Fair Value 18,616 27,564
Gross Unrealized Losses 2,672 4,292
Asset-backed securities    
Debt Securities [Line Items]    
Less than Twelve Months, Fair Value 2,538 1,488
Less than Twelve Months, Unrealized Losses 36 11
Twelve Months or More, Fair Value 732 1,015
Twelve Months or More, Unrealized Losses 32 48
Fair Value 3,270 2,503
Gross Unrealized Losses 68 59
Commercial mortgage-backed securities    
Debt Securities [Line Items]    
Less than Twelve Months, Fair Value 282 1,092
Less than Twelve Months, Unrealized Losses 1 8
Twelve Months or More, Fair Value 6,123 6,432
Twelve Months or More, Unrealized Losses 403 539
Fair Value 6,405 7,524
Gross Unrealized Losses 404 547
Residential mortgage-backed securities    
Debt Securities [Line Items]    
Less than Twelve Months, Fair Value 201 361
Less than Twelve Months, Unrealized Losses 2 4
Twelve Months or More, Fair Value 1,351 1,377
Twelve Months or More, Unrealized Losses 183 219
Fair Value 1,552 1,738
Gross Unrealized Losses $ 185 $ 223