Investments - Unrealized Capital Losses (Details) $ in Millions | Jun. 30, 2023 USD ($) securities | Dec. 31, 2022 USD ($) 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 | 946 | |
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss | $ 2,397 | $ 2,628 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months | $ 228 | |
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions | securities | 4,046 | 4,222 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Number of Positions | securities | 3,100 | 1,069 |
Debt Securities, Available-for-sale, Unrealized Loss Position | $ 12,400 | $ 3,143 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value | 4,685 | |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer | 2,169 | 861 |
Debt Securities, Available-for-sale, Unrealized Loss Position, Fair Value | $ 17,085 | 18,531 |
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Fair Value | | 15,388 |
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Accumulated Loss | | $ 1,767 |
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Number of Securities | securities | | 3,153 |
Fair value decline below amortized cost greater than 20% | | |
Available-for-sale Securities Including Securities Pledged [Line Items] | | |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Number of Positions | securities | 543 | |
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss | $ 618 | |
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 | 23 | |
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss | $ 23 | $ 31 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months | $ 3 | |
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions | securities | 33 | 21 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Number of Positions | securities | 10 | 3 |
Debt Securities, Available-for-sale, Unrealized Loss Position | $ 81 | $ 2 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value | 120 | |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer | 20 | 1 |
Debt Securities, Available-for-sale, Unrealized Loss Position, Fair Value | $ 201 | 225 |
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Fair Value | | 223 |
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Accumulated Loss | | $ 30 |
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Number of Securities | securities | | 18 |
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 | 76 | |
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss | $ 76 | $ 92 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months | $ 8 | |
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions | securities | 288 | 292 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Number of Positions | securities | 212 | 16 |
Debt Securities, Available-for-sale, Unrealized Loss Position | $ 411 | $ 15 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value | 155 | |
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 | $ 566 | 560 |
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Fair Value | | 545 |
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Accumulated Loss | | $ 85 |
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Number of Securities | securities | | 276 |
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 | 278 | |
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss | $ 902 | $ 1,032 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months | $ 72 | |
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions | securities | 1,191 | 1,261 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Number of Positions | securities | 913 | 360 |
Debt Securities, Available-for-sale, Unrealized Loss Position | $ 3,470 | $ 998 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value | 1,345 | |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer | 830 | 419 |
Debt Securities, Available-for-sale, Unrealized Loss Position, Fair Value | $ 4,815 | 5,288 |
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Fair Value | | 4,290 |
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Accumulated Loss | | $ 613 |
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Number of Securities | securities | | 901 |
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 | 95 | |
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss | $ 325 | $ 328 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months | $ 44 | |
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions | securities | 333 | 344 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Number of Positions | securities | 238 | 32 |
Debt Securities, Available-for-sale, Unrealized Loss Position | $ 2,049 | $ 331 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value | 949 | |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer | 281 | 64 |
Debt Securities, Available-for-sale, Unrealized Loss Position, Fair Value | $ 2,998 | 3,150 |
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Fair Value | | 2,819 |
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Accumulated Loss | | $ 264 |
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Number of Securities | securities | | 312 |
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 | 94 | |
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss | $ 266 | $ 317 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months | $ 16 | |
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions | securities | 411 | 441 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Number of Positions | securities | 317 | 93 |
Debt Securities, Available-for-sale, Unrealized Loss Position | $ 1,188 | $ 298 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value | 459 | |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer | 250 | 116 |
Debt Securities, Available-for-sale, Unrealized Loss Position, Fair Value | $ 1,647 | 1,807 |
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Fair Value | | 1,509 |
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Accumulated Loss | | $ 201 |
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Number of Securities | securities | | 348 |
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 | 66 | |
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss | $ 158 | $ 184 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months | $ 27 | |
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions | securities | 193 | 206 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Number of Positions | securities | 127 | 6 |
Debt Securities, Available-for-sale, Unrealized Loss Position | $ 1,265 | $ 52 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value | 814 | |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer | 131 | 11 |
Debt Securities, Available-for-sale, Unrealized Loss Position, Fair Value | $ 2,079 | 2,255 |
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Fair Value | | 2,203 |
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Accumulated Loss | | $ 173 |
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Number of Securities | securities | | 200 |
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 | 205 | |
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss | $ 141 | $ 153 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months | $ 17 | |
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions | securities | 621 | 656 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Number of Positions | securities | 416 | 215 |
Debt Securities, Available-for-sale, Unrealized Loss Position | $ 712 | $ 328 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value | 355 | |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer | 124 | 75 |
Debt Securities, Available-for-sale, Unrealized Loss Position, Fair Value | $ 1,067 | 1,393 |
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Fair Value | | 1,065 |
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Accumulated Loss | | $ 78 |
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Number of Securities | securities | | 441 |
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 | 72 | |
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss | $ 418 | $ 379 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months | $ 36 | |
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions | securities | 547 | 562 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Number of Positions | securities | 475 | 189 |
Debt Securities, Available-for-sale, Unrealized Loss Position | $ 2,062 | $ 759 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value | 355 | |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer | 382 | 127 |
Debt Securities, Available-for-sale, Unrealized Loss Position, Fair Value | $ 2,417 | 2,551 |
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Fair Value | | 1,792 |
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Accumulated Loss | | $ 252 |
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Number of Securities | securities | | 373 |
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 | 36 | |
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss | $ 85 | $ 109 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months | $ 5 | |
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions | securities | 426 | 436 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Number of Positions | securities | 390 | 155 |
Debt Securities, Available-for-sale, Unrealized Loss Position | $ 1,145 | $ 360 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value | 120 | |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer | 80 | 41 |
Debt Securities, Available-for-sale, Unrealized Loss Position, Fair Value | $ 1,265 | 1,272 |
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Fair Value | | 912 |
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Accumulated Loss | | $ 68 |
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Number of Securities | securities | | 281 |
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 | 1 | |
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss | $ 3 | |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months | $ 0 | |
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions | securities | 3 | |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Number of Positions | securities | 2 | |
Debt Securities, Available-for-sale, Unrealized Loss Position | $ 17 | |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value | 13 | |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer | 3 | |
Debt Securities, Available-for-sale, Unrealized Loss Position, Fair Value | $ 30 | |
US Treasury and Government | | |
Available-for-sale Securities Including Securities Pledged [Line Items] | | |
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss | | $ 3 |
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions | securities | | 3 |
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, 12 Months or Longer | | 0 |
Debt Securities, Available-for-sale, Unrealized Loss Position, Fair Value | | 30 |
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Fair Value | | 30 |
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Accumulated Loss | | $ 3 |
Debt Securities, Available-for-sale, Including Securities Pledged, Continuous Unrealized Loss Position Twelve Months or Less, Number of Securities | securities | | 3 |