v3.25.0.1
Investments - Unrealized Loss Position (Details)
$ in Millions
Dec. 31, 2024
USD ($)
security
Dec. 31, 2023
USD ($)
security
Number of Securities    
Number of Securities, Less than 12 months | security 4,502 1,182
Number of Securities, Greater than 12 months | security 4,174 7,018
Number of Securities | security 8,676 8,200
Fair Value    
Fair Value, Less than 12 months $ 7,506 $ 1,932
Fair Value, Greater than 12 months 5,734 10,616
Fair Value 13,240 12,548
Unrealized Losses    
Unrealized Losses, Less than 12 months 127 28
Unrealized Losses, Greater than 12 months 580 808
Unrealized Losses $ 707 $ 836
U.S. government securities    
Number of Securities    
Number of Securities, Less than 12 months | security 266 74
Number of Securities, Greater than 12 months | security 155 280
Number of Securities | security 421 354
Fair Value    
Fair Value, Less than 12 months $ 1,053 $ 194
Fair Value, Greater than 12 months 394 891
Fair Value 1,447 1,085
Unrealized Losses    
Unrealized Losses, Less than 12 months 18 2
Unrealized Losses, Greater than 12 months 20 52
Unrealized Losses $ 38 $ 54
States, municipalities and political subdivisions    
Number of Securities    
Number of Securities, Less than 12 months | security 100 95
Number of Securities, Greater than 12 months | security 137 455
Number of Securities | security 237 550
Fair Value    
Fair Value, Less than 12 months $ 181 $ 181
Fair Value, Greater than 12 months 201 733
Fair Value 382 914
Unrealized Losses    
Unrealized Losses, Less than 12 months 3 1
Unrealized Losses, Greater than 12 months 15 34
Unrealized Losses $ 18 $ 35
U.S. corporate securities    
Number of Securities    
Number of Securities, Less than 12 months | security 3,119 576
Number of Securities, Greater than 12 months | security 2,602 4,120
Number of Securities | security 5,721 4,696
Fair Value    
Fair Value, Less than 12 months $ 4,144 $ 672
Fair Value, Greater than 12 months 3,395 5,602
Fair Value 7,539 6,274
Unrealized Losses    
Unrealized Losses, Less than 12 months 64 14
Unrealized Losses, Greater than 12 months 348 432
Unrealized Losses $ 412 $ 446
Foreign securities    
Number of Securities    
Number of Securities, Less than 12 months | security 599 160
Number of Securities, Greater than 12 months | security 616 964
Number of Securities | security 1,215 1,124
Fair Value    
Fair Value, Less than 12 months $ 810 $ 243
Fair Value, Greater than 12 months 874 1,407
Fair Value 1,684 1,650
Unrealized Losses    
Unrealized Losses, Less than 12 months 21 4
Unrealized Losses, Greater than 12 months 90 118
Unrealized Losses $ 111 $ 122
Residential mortgage-backed securities    
Number of Securities    
Number of Securities, Less than 12 months | security 89 33
Number of Securities, Greater than 12 months | security 361 461
Number of Securities | security 450 494
Fair Value    
Fair Value, Less than 12 months $ 267 $ 97
Fair Value, Greater than 12 months 342 517
Fair Value 609 614
Unrealized Losses    
Unrealized Losses, Less than 12 months 5 1
Unrealized Losses, Greater than 12 months 49 59
Unrealized Losses $ 54 $ 60
Commercial mortgage-backed securities    
Number of Securities    
Number of Securities, Less than 12 months | security 186 44
Number of Securities, Greater than 12 months | security 237 287
Number of Securities | security 423 331
Fair Value    
Fair Value, Less than 12 months $ 628 $ 94
Fair Value, Greater than 12 months 464 581
Fair Value 1,092 675
Unrealized Losses    
Unrealized Losses, Less than 12 months 11 2
Unrealized Losses, Greater than 12 months 56 98
Unrealized Losses $ 67 $ 100
Other asset-backed securities    
Number of Securities    
Number of Securities, Less than 12 months | security 139 196
Number of Securities, Greater than 12 months | security 62 443
Number of Securities | security 201 639
Fair Value    
Fair Value, Less than 12 months $ 414 $ 449
Fair Value, Greater than 12 months 58 867
Fair Value 472 1,316
Unrealized Losses    
Unrealized Losses, Less than 12 months 5 4
Unrealized Losses, Greater than 12 months 2 14
Unrealized Losses $ 7 $ 18
Redeemable preferred securities    
Number of Securities    
Number of Securities, Less than 12 months | security 4 4
Number of Securities, Greater than 12 months | security 4 8
Number of Securities | security 8 12
Fair Value    
Fair Value, Less than 12 months $ 9 $ 2
Fair Value, Greater than 12 months 6 18
Fair Value 15 20
Unrealized Losses    
Unrealized Losses, Less than 12 months 0 0
Unrealized Losses, Greater than 12 months 0 1
Unrealized Losses $ 0 $ 1