v3.26.1
Investments - Schedule of Debt Securities in Continuous Unrealized Loss Position (Details)
$ in Millions
Jun. 30, 2026
USD ($)
security
Dec. 31, 2025
USD ($)
security
Summary of Investment Holdings [Line Items]    
Less than 12 months, gross unrealized losses $ 194 $ 74
Less than 12 months, fair value $ 14,811 $ 3,714
Less than 12 months, # of securities | security 1,494 427
12 months or longer, gross unrealized losses $ 3,720 $ 3,677
12 months or longer, fair value $ 18,749 $ 20,885
12 months or longer, # of securities | security 2,257 2,474
Total, gross unrealized losses $ 3,914 $ 3,751
Total, fair value $ 33,560 $ 24,599
Total, # of securities | security 3,612 2,848
U.S. government securities    
Summary of Investment Holdings [Line Items]    
Less than 12 months, gross unrealized losses $ 5 $ 2
Less than 12 months, fair value $ 365 $ 68
Less than 12 months, # of securities | security 28 16
12 months or longer, gross unrealized losses $ 861 $ 849
12 months or longer, fair value $ 2,239 $ 2,263
12 months or longer, # of securities | security 20 20
Total, gross unrealized losses $ 866 $ 851
Total, fair value $ 2,604 $ 2,331
Total, # of securities | security 43 31
Other government securities    
Summary of Investment Holdings [Line Items]    
Less than 12 months, gross unrealized losses $ 2 $ 1
Less than 12 months, fair value $ 97 $ 48
Less than 12 months, # of securities | security 27 7
12 months or longer, gross unrealized losses $ 182 $ 192
12 months or longer, fair value $ 777 $ 887
12 months or longer, # of securities | security 97 107
Total, gross unrealized losses $ 184 $ 193
Total, fair value $ 874 $ 935
Total, # of securities | security 122 113
Public utilities    
Summary of Investment Holdings [Line Items]    
Less than 12 months, gross unrealized losses $ 20 $ 7
Less than 12 months, fair value $ 1,458 $ 419
Less than 12 months, # of securities | security 146 44
12 months or longer, gross unrealized losses $ 484 $ 451
12 months or longer, fair value $ 3,176 $ 3,383
12 months or longer, # of securities | security 390 415
Total, gross unrealized losses $ 504 $ 458
Total, fair value $ 4,634 $ 3,802
Total, # of securities | security 520 454
Corporate securities    
Summary of Investment Holdings [Line Items]    
Less than 12 months, gross unrealized losses $ 127 $ 44
Less than 12 months, fair value $ 9,619 $ 2,300
Less than 12 months, # of securities | security 966 240
12 months or longer, gross unrealized losses $ 2,014 $ 1,998
12 months or longer, fair value $ 10,601 $ 12,130
12 months or longer, # of securities | security 1,361 1,502
Total, gross unrealized losses $ 2,141 $ 2,042
Total, fair value $ 20,220 $ 14,430
Total, # of securities | security 2,224 1,706
Residential mortgage-backed    
Summary of Investment Holdings [Line Items]    
Less than 12 months, gross unrealized losses $ 8 $ 2
Less than 12 months, fair value $ 138 $ 43
Less than 12 months, # of securities | security 73 21
12 months or longer, gross unrealized losses $ 21 $ 21
12 months or longer, fair value $ 134 $ 172
12 months or longer, # of securities | security 145 166
Total, gross unrealized losses $ 29 $ 23
Total, fair value $ 272 $ 215
Total, # of securities | security 217 187
Commercial mortgage-backed    
Summary of Investment Holdings [Line Items]    
Less than 12 months, gross unrealized losses $ 6 $ 2
Less than 12 months, fair value $ 660 $ 163
Less than 12 months, # of securities | security 79 30
12 months or longer, gross unrealized losses $ 56 $ 52
12 months or longer, fair value $ 739 $ 801
12 months or longer, # of securities | security 109 117
Total, gross unrealized losses $ 62 $ 54
Total, fair value $ 1,399 $ 964
Total, # of securities | security 180 146
Other asset-backed securities    
Summary of Investment Holdings [Line Items]    
Less than 12 months, gross unrealized losses $ 26 $ 16
Less than 12 months, fair value $ 2,474 $ 673
Less than 12 months, # of securities | security 175 69
12 months or longer, gross unrealized losses $ 102 $ 114
12 months or longer, fair value $ 1,083 $ 1,249
12 months or longer, # of securities | security 135 147
Total, gross unrealized losses $ 128 $ 130
Total, fair value $ 3,557 $ 1,922
Total, # of securities | security 306 211