v3.26.1
Investments - Schedule of Gross Unrealized Losses and Fair Value of Investment Securities (Details)
$ in Millions
Mar. 31, 2026
USD ($)
security
Dec. 31, 2025
USD ($)
security
Schedule of Investments [Line Items]    
Less than 12 months, Fair value $ 7,344 $ 2,786
Less than 12 months, Gross unrealized losses $ (155) $ (82)
Less than 12 months, Number of securities in a continuous loss position | security 1,590 610
12 months or more, Fair value $ 22,213 $ 23,303
12 months or more, Gross unrealized losses $ (3,528) $ (3,145)
12 months or more, Number of securities in a continuous loss position | security 3,023 3,069
Fair value $ 29,557 $ 26,089
Gross unrealized losses $ (3,683) $ (3,227)
Number of securities | security 4,613 3,679
Investment grade    
Schedule of Investments [Line Items]    
Less than 12 months, Fair value $ 7,127 $ 2,705
Less than 12 months, Gross unrealized losses $ (142) $ (71)
Less than 12 months, Number of securities in a continuous loss position | security 1,534 582
12 months or more, Fair value $ 21,688 $ 22,737
12 months or more, Gross unrealized losses $ (3,462) $ (3,096)
12 months or more, Number of securities in a continuous loss position | security 2,947 2,991
Fair value $ 28,815 $ 25,442
Gross unrealized losses $ (3,604) $ (3,167)
Number of securities | security 4,481 3,573
Below investment grade    
Schedule of Investments [Line Items]    
Less than 12 months, Fair value $ 217 $ 81
Less than 12 months, Gross unrealized losses $ (13) $ (11)
Less than 12 months, Number of securities in a continuous loss position | security 56 28
12 months or more, Fair value $ 525 $ 566
12 months or more, Gross unrealized losses $ (66) $ (49)
12 months or more, Number of securities in a continuous loss position | security 76 78
Fair value $ 742 $ 647
Gross unrealized losses $ (79) $ (60)
Number of securities | security 132 106
Less Than 20% Below cost    
Schedule of Investments [Line Items]    
Less than 12 months, Fair value $ 7,317 $ 2,731
Less than 12 months, Gross unrealized losses $ (142) $ (61)
Less than 12 months, Number of securities in a continuous loss position | security 1,581 593
12 months or more, Fair value $ 17,770 $ 19,932
12 months or more, Gross unrealized losses $ (1,928) $ (1,928)
12 months or more, Number of securities in a continuous loss position | security 2,395 2,587
Fair value $ 25,087 $ 22,663
Gross unrealized losses $ (2,070) $ (1,989)
Number of securities | security 3,976 3,180
20%-50% Below cost    
Schedule of Investments [Line Items]    
Less than 12 months, Fair value $ 27 $ 55
Less than 12 months, Gross unrealized losses $ (13) $ (21)
Less than 12 months, Number of securities in a continuous loss position | security 9 17
12 months or more, Fair value $ 4,443 $ 3,370
12 months or more, Gross unrealized losses $ (1,600) $ (1,216)
12 months or more, Number of securities in a continuous loss position | security 628 481
Fair value $ 4,470 $ 3,425
Gross unrealized losses $ (1,613) $ (1,237)
Number of securities | security 637 498
Greater Than 50% Below Cost    
Schedule of Investments [Line Items]    
Less than 12 months, Fair value   $ 0
Less than 12 months, Gross unrealized losses   $ 0
Less than 12 months, Number of securities in a continuous loss position | security   0
12 months or more, Fair value   $ 1
12 months or more, Gross unrealized losses   $ (1)
12 months or more, Number of securities in a continuous loss position | security   1
Fair value   $ 1
Gross unrealized losses   $ (1)
Number of securities | security   1
U.S. government, agencies and government-sponsored enterprises    
Schedule of Investments [Line Items]    
Less than 12 months, Fair value $ 495 $ 438
Less than 12 months, Gross unrealized losses $ (12) $ (9)
Less than 12 months, Number of securities in a continuous loss position | security 37 28
12 months or more, Fair value $ 1,662 $ 1,626
12 months or more, Gross unrealized losses $ (389) $ (355)
12 months or more, Number of securities in a continuous loss position | security 60 68
Fair value $ 2,157 $ 2,064
Gross unrealized losses $ (401) $ (364)
Number of securities | security 97 96
State and political subdivisions    
Schedule of Investments [Line Items]    
Less than 12 months, Fair value $ 136 $ 79
Less than 12 months, Gross unrealized losses $ (4) $ (2)
Less than 12 months, Number of securities in a continuous loss position | security 34 18
12 months or more, Fair value $ 1,458 $ 1,577
12 months or more, Gross unrealized losses $ (261) $ (253)
12 months or more, Number of securities in a continuous loss position | security 248 257
Fair value $ 1,594 $ 1,656
Gross unrealized losses $ (265) $ (255)
Number of securities | security 282 275
Non-U.S. government    
Schedule of Investments [Line Items]    
Less than 12 months, Fair value $ 348 $ 115
Less than 12 months, Gross unrealized losses $ (11) $ (1)
Less than 12 months, Number of securities in a continuous loss position | security 109 36
12 months or more, Fair value $ 365 $ 399
12 months or more, Gross unrealized losses $ (86) $ (74)
12 months or more, Number of securities in a continuous loss position | security 52 55
Fair value $ 713 $ 514
Gross unrealized losses $ (97) $ (75)
Number of securities | security 161 91
U.S. corporate    
Schedule of Investments [Line Items]    
Less than 12 months, Fair value $ 4,053 $ 1,664
Less than 12 months, Gross unrealized losses $ (98) $ (57)
Less than 12 months, Number of securities in a continuous loss position | security 905 399
12 months or more, Fair value $ 13,471 $ 14,057
12 months or more, Gross unrealized losses $ (2,085) $ (1,811)
12 months or more, Number of securities in a continuous loss position | security 1,858 1,814
Fair value $ 17,524 $ 15,721
Gross unrealized losses $ (2,183) $ (1,868)
Number of securities | security 2,763 2,213
Non-U.S. corporate    
Schedule of Investments [Line Items]    
Less than 12 months, Fair value $ 1,301 $ 244
Less than 12 months, Gross unrealized losses $ (22) $ (11)
Less than 12 months, Number of securities in a continuous loss position | security 245 57
12 months or more, Fair value $ 3,270 $ 3,495
12 months or more, Gross unrealized losses $ (408) $ (366)
12 months or more, Number of securities in a continuous loss position | security 409 438
Fair value $ 4,571 $ 3,739
Gross unrealized losses $ (430) $ (377)
Number of securities | security 654 495
Residential mortgage-backed    
Schedule of Investments [Line Items]    
Less than 12 months, Fair value $ 149 $ 0
Less than 12 months, Gross unrealized losses $ (2) $ 0
Less than 12 months, Number of securities in a continuous loss position | security 64 0
12 months or more, Fair value $ 350 $ 391
12 months or more, Gross unrealized losses $ (35) $ (34)
12 months or more, Number of securities in a continuous loss position | security 123 140
Fair value $ 499 $ 391
Gross unrealized losses $ (37) $ (34)
Number of securities | security 187 140
Commercial mortgage-backed    
Schedule of Investments [Line Items]    
Less than 12 months, Fair value $ 136 $ 59
Less than 12 months, Gross unrealized losses $ (2) $ (1)
Less than 12 months, Number of securities in a continuous loss position | security 38 15
12 months or more, Fair value $ 1,098 $ 1,118
12 months or more, Gross unrealized losses $ (235) $ (225)
12 months or more, Number of securities in a continuous loss position | security 163 169
Fair value $ 1,234 $ 1,177
Gross unrealized losses $ (237) $ (226)
Number of securities | security 201 184
Other asset-backed    
Schedule of Investments [Line Items]    
Less than 12 months, Fair value $ 726 $ 187
Less than 12 months, Gross unrealized losses $ (4) $ (1)
Less than 12 months, Number of securities in a continuous loss position | security 158 57
12 months or more, Fair value $ 539 $ 640
12 months or more, Gross unrealized losses $ (29) $ (27)
12 months or more, Number of securities in a continuous loss position | security 110 128
Fair value $ 1,265 $ 827
Gross unrealized losses $ (33) $ (28)
Number of securities | security 268 185