v3.26.3
Investments - Schedule of Debt Securities in Continuous Unrealized Loss Position (Details)
$ in Millions
Sep. 30, 2026
USD ($)
security
Dec. 31, 2025
USD ($)
security
Summary of Investment Holdings [Line Items]    
Less than 12 months, gross unrealized losses $ 1,223 $ 74
Less than 12 months, fair value $ 30,897 $ 3,714
Less than 12 months, # of securities | security 2,801 427
12 months or longer, gross unrealized losses $ 4,633 $ 3,677
12 months or longer, fair value $ 17,349 $ 20,885
12 months or longer, # of securities | security 2,197 2,474
Total, gross unrealized losses $ 5,856 $ 3,751
Total, fair value $ 48,246 $ 24,599
Total, # of securities | security 4,775 2,848
U.S. government securities    
Summary of Investment Holdings [Line Items]    
Less than 12 months, gross unrealized losses $ 19 $ 2
Less than 12 months, fair value $ 2,037 $ 68
Less than 12 months, # of securities | security 33 16
12 months or longer, gross unrealized losses $ 993 $ 849
12 months or longer, fair value $ 2,092 $ 2,263
12 months or longer, # of securities | security 18 20
Total, gross unrealized losses $ 1,012 $ 851
Total, fair value $ 4,129 $ 2,331
Total, # of securities | security 46 31
Other government securities    
Summary of Investment Holdings [Line Items]    
Less than 12 months, gross unrealized losses $ 14 $ 1
Less than 12 months, fair value $ 282 $ 48
Less than 12 months, # of securities | security 104 7
12 months or longer, gross unrealized losses $ 241 $ 192
12 months or longer, fair value $ 724 $ 887
12 months or longer, # of securities | security 97 107
Total, gross unrealized losses $ 255 $ 193
Total, fair value $ 1,006 $ 935
Total, # of securities | security 198 113
Public utilities    
Summary of Investment Holdings [Line Items]    
Less than 12 months, gross unrealized losses $ 176 $ 7
Less than 12 months, fair value $ 3,326 $ 419
Less than 12 months, # of securities | security 306 44
12 months or longer, gross unrealized losses $ 674 $ 451
12 months or longer, fair value $ 2,980 $ 3,383
12 months or longer, # of securities | security 387 415
Total, gross unrealized losses $ 850 $ 458
Total, fair value $ 6,306 $ 3,802
Total, # of securities | security 659 454
Corporate securities    
Summary of Investment Holdings [Line Items]    
Less than 12 months, gross unrealized losses $ 866 $ 44
Less than 12 months, fair value $ 19,753 $ 2,300
Less than 12 months, # of securities | security 1,885 240
12 months or longer, gross unrealized losses $ 2,504 $ 1,998
12 months or longer, fair value $ 9,710 $ 12,130
12 months or longer, # of securities | security 1,311 1,502
Total, gross unrealized losses $ 3,370 $ 2,042
Total, fair value $ 29,463 $ 14,430
Total, # of securities | security 3,031 1,706
Residential mortgage-backed    
Summary of Investment Holdings [Line Items]    
Less than 12 months, gross unrealized losses $ 15 $ 2
Less than 12 months, fair value $ 234 $ 43
Less than 12 months, # of securities | security 112 21
12 months or longer, gross unrealized losses $ 32 $ 21
12 months or longer, fair value $ 125 $ 172
12 months or longer, # of securities | security 146 166
Total, gross unrealized losses $ 47 $ 23
Total, fair value $ 359 $ 215
Total, # of securities | security 257 187
Commercial mortgage-backed    
Summary of Investment Holdings [Line Items]    
Less than 12 months, gross unrealized losses $ 22 $ 2
Less than 12 months, fair value $ 960 $ 163
Less than 12 months, # of securities | security 109 30
12 months or longer, gross unrealized losses $ 66 $ 52
12 months or longer, fair value $ 708 $ 801
12 months or longer, # of securities | security 110 117
Total, gross unrealized losses $ 88 $ 54
Total, fair value $ 1,668 $ 964
Total, # of securities | security 208 146
Other asset-backed securities    
Summary of Investment Holdings [Line Items]    
Less than 12 months, gross unrealized losses $ 111 $ 16
Less than 12 months, fair value $ 4,305 $ 673
Less than 12 months, # of securities | security 252 69
12 months or longer, gross unrealized losses $ 123 $ 114
12 months or longer, fair value $ 1,010 $ 1,249
12 months or longer, # of securities | security 128 147
Total, gross unrealized losses $ 234 $ 130
Total, fair value $ 5,315 $ 1,922
Total, # of securities | security 376 211