Investments - Unrealized Capital Losses (Details) $ in Millions | Mar. 31, 2022USD ($)securities | Dec. 31, 2021USD ($)securities |
Available-for-sale Securities Including Securities Pledged [Line Items] | | |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Number of Positions | securities | 2,036 | 989 |
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss | $ 674 | $ 111 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months | $ 538 | $ 72 |
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions | securities | 2,481 | 1,326 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Number of Positions | securities | 445 | 337 |
Debt Securities, Available-for-sale, Unrealized Loss Position | $ 1,144 | $ 708 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value | 9,317 | 3,838 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer | 136 | 39 |
Debt Securities, Available-for-sale, Unrealized Loss Position, Fair Value | $ 10,461 | $ 4,546 |
U.S. Treasuries | | |
Available-for-sale Securities Including Securities Pledged [Line Items] | | |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Number of Positions | securities | 13 | 4 |
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss | $ 7 | $ 0 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months | $ 7 | $ 0 |
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions | securities | 16 | 6 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Number of Positions | securities | 3 | 2 |
Debt Securities, Available-for-sale, Unrealized Loss Position | $ 8 | $ 7 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value | 100 | 7 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer | 0 | 0 |
Debt Securities, Available-for-sale, Unrealized Loss Position, Fair Value | $ 108 | $ 14 |
State, municipalities and political subdivisions | | |
Available-for-sale Securities Including Securities Pledged [Line Items] | | |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Number of Positions | securities | 86 | 21 |
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss | $ 14 | $ 1 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months | $ 14 | $ 1 |
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions | securities | 86 | 21 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Number of Positions | securities | 0 | 0 |
Debt Securities, Available-for-sale, Unrealized Loss Position | $ 0 | $ 0 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value | 167 | 33 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer | 0 | 0 |
Debt Securities, Available-for-sale, Unrealized Loss Position, Fair Value | $ 167 | $ 33 |
U.S. corporate public securities | | |
Available-for-sale Securities Including Securities Pledged [Line Items] | | |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Number of Positions | securities | 542 | 290 |
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss | $ 298 | $ 39 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months | $ 230 | $ 32 |
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions | securities | 729 | 428 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Number of Positions | securities | 187 | 138 |
Debt Securities, Available-for-sale, Unrealized Loss Position | $ 362 | $ 110 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value | 2,358 | 1,237 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer | 68 | 7 |
Debt Securities, Available-for-sale, Unrealized Loss Position, Fair Value | $ 2,720 | $ 1,347 |
U.S. corporate private securities | | |
Available-for-sale Securities Including Securities Pledged [Line Items] | | |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Number of Positions | securities | 153 | 35 |
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss | $ 77 | $ 15 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months | $ 62 | $ 2 |
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions | securities | 162 | 43 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Number of Positions | securities | 9 | 8 |
Debt Securities, Available-for-sale, Unrealized Loss Position | $ 94 | $ 94 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value | 1,352 | 325 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer | 15 | 13 |
Debt Securities, Available-for-sale, Unrealized Loss Position, Fair Value | $ 1,446 | $ 419 |
Foreign corporate public securities and foreign governments | | |
Available-for-sale Securities Including Securities Pledged [Line Items] | | |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Number of Positions | securities | 193 | 90 |
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss | $ 93 | $ 14 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months | $ 68 | $ 13 |
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions | securities | 235 | 107 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Number of Positions | securities | 42 | 17 |
Debt Securities, Available-for-sale, Unrealized Loss Position | $ 152 | $ 21 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value | 843 | 425 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer | 25 | 1 |
Debt Securities, Available-for-sale, Unrealized Loss Position, Fair Value | $ 995 | $ 446 |
Foreign corporate private securities | | |
Available-for-sale Securities Including Securities Pledged [Line Items] | | |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Number of Positions | securities | 77 | 7 |
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss | $ 28 | $ 1 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months | $ 28 | $ 1 |
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions | securities | 78 | 8 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Number of Positions | securities | 1 | 1 |
Debt Securities, Available-for-sale, Unrealized Loss Position | $ 10 | $ 10 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value | 871 | 54 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer | 0 | 0 |
Debt Securities, Available-for-sale, Unrealized Loss Position, Fair Value | $ 881 | $ 64 |
Residential mortgage-backed | | |
Available-for-sale Securities Including Securities Pledged [Line Items] | | |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Number of Positions | securities | 300 | 181 |
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss | $ 52 | $ 20 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months | $ 39 | $ 11 |
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions | securities | 415 | 277 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Number of Positions | securities | 115 | 96 |
Debt Securities, Available-for-sale, Unrealized Loss Position | $ 254 | $ 241 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value | 921 | 400 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer | 13 | 9 |
Debt Securities, Available-for-sale, Unrealized Loss Position, Fair Value | $ 1,175 | $ 641 |
Commercial mortgage-backed | | |
Available-for-sale Securities Including Securities Pledged [Line Items] | | |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Number of Positions | securities | 376 | 178 |
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss | $ 79 | $ 15 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months | $ 68 | $ 8 |
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions | securities | 407 | 205 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Number of Positions | securities | 31 | 27 |
Debt Securities, Available-for-sale, Unrealized Loss Position | $ 171 | $ 155 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value | 1,681 | 780 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer | 11 | 7 |
Debt Securities, Available-for-sale, Unrealized Loss Position, Fair Value | $ 1,852 | $ 935 |
Other asset-backed securities | | |
Available-for-sale Securities Including Securities Pledged [Line Items] | | |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Number of Positions | securities | 294 | 183 |
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss | $ 25 | $ 6 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months | $ 21 | $ 4 |
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions | securities | 351 | 231 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Number of Positions | securities | 57 | 48 |
Debt Securities, Available-for-sale, Unrealized Loss Position | $ 93 | $ 70 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value | 1,005 | 577 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer | 4 | 2 |
Debt Securities, Available-for-sale, Unrealized Loss Position, Fair Value | $ 1,098 | $ 647 |
US Government Corporations and Agencies Securities | | |
Available-for-sale Securities Including Securities Pledged [Line Items] | | |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Number of Positions | securities | 2 | |
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss | $ 1 | |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months | $ 1 | |
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions | securities | 2 | |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Number of Positions | securities | 0 | |
Debt Securities, Available-for-sale, Unrealized Loss Position | $ 0 | |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value | 19 | |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer | 0 | |
Debt Securities, Available-for-sale, Unrealized Loss Position, Fair Value | $ 19 | |