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Unpaid losses and loss expenses Unpaid Losses and loss expenses, claims development (Cumulative Net incurred Loss and Allocated Loss Adjustment Expense) (Details) $ in Millions | Dec. 31, 2023 USD ($) | Dec. 31, 2022 USD ($) | Dec. 31, 2021 USD ($) | Dec. 31, 2020 USD ($) | Dec. 31, 2019 USD ($) | Dec. 31, 2018 USD ($) | Dec. 31, 2017 USD ($) | Dec. 31, 2016 USD ($) | Dec. 31, 2015 USD ($) | Dec. 31, 2014 USD ($)
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Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net | $ 60,209 |  |  |  |  |  |  |  |  |
North America Commercial P&C Insurance - Workers' Compensation [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | 12,508 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 5,289 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net | 10,159 |  |  |  |  |  |  |  |  |
North America Commercial P&C Insurance - Liability [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | 39,558 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 20,402 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net | 21,092 |  |  |  |  |  |  |  |  |
North America Commercial P&C Insurance - Other Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | 6,453 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 4,085 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net | 2,596 |  |  |  |  |  |  |  |  |
North America Commercial P&C Insurance - Non-Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | 22,885 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 19,669 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net | 3,203 |  |  |  |  |  |  |  |  |
North America Personal P&C Insurance [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | 28,150 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 24,647 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net | 3,550 |  |  |  |  |  |  |  |  |
Overseas General Insurance - Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | 14,455 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 6,838 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net | 8,157 |  |  |  |  |  |  |  |  |
Overseas General Insurance - Non-Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | 21,925 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 18,549 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net | 3,515 |  |  |  |  |  |  |  |  |
Global Reinsurance - Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | 2,685 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 1,724 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net | 1,240 |  |  |  |  |  |  |  |  |
Global Reinsurance - Non-Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | 2,481 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 2,081 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net | 411 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Accident Year 2014 [Member] | North America Commercial P&C Insurance - Workers' Compensation [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | 983 | $ 1,007 | $ 1,037 | $ 1,073 | $ 1,100 | $ 1,163 | $ 1,215 | $ 1,217 | $ 1,201 | $ 1,207
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 236 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 649 | 634 | 617 | 599 | 566 | 532 | 484 | 410 | 295 | 113
Cumulative Number of Reported Claims | 45,000 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Accident Year 2014 [Member] | North America Commercial P&C Insurance - Liability [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 3,134 | 3,142 | 3,192 | 3,340 | 3,463 | 3,649 | 3,710 | 3,667 | 3,578 | 3,528
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 237 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 2,802 | 2,753 | 2,669 | 2,580 | 2,439 | 2,199 | 1,801 | 1,248 | 679 | 164
Cumulative Number of Reported Claims | 24,000 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Accident Year 2014 [Member] | North America Commercial P&C Insurance - Other Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 530 | 526 | 530 | 538 | 538 | 554 | 595 | 580 | 582 | 594
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 9 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 517 | 513 | 508 | 500 | 473 | 454 | 391 | 317 | 220 | 80
Cumulative Number of Reported Claims | 17,000 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Accident Year 2014 [Member] | North America Commercial P&C Insurance - Non-Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 1,554 | 1,544 | 1,545 | 1,552 | 1,544 | 1,543 | 1,552 | 1,573 | 1,655 | 1,635
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 0 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 1,551 | 1,552 | 1,552 | 1,547 | 1,540 | 1,525 | 1,499 | 1,478 | 1,368 | 816
Cumulative Number of Reported Claims | 483,000 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Accident Year 2014 [Member] | North America Personal P&C Insurance [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 2,130 | 2,133 | 2,134 | 2,135 | 2,140 | 2,153 | 2,139 | 2,186 | 2,199 | 2,198
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 6 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 2,121 | 2,119 | 2,116 | 2,109 | 2,100 | 2,073 | 2,028 | 1,919 | 1,759 | 1,306
Cumulative Number of Reported Claims | 144,000 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Accident Year 2014 [Member] | Overseas General Insurance - Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 1,089 | 1,106 | 1,103 | 1,093 | 1,129 | 1,210 | 1,290 | 1,271 | 1,264 | 1,196
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 46 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 934 | 894 | 865 | 823 | 761 | 681 | 571 | 444 | 275 | 105
Cumulative Number of Reported Claims | 38,000 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Accident Year 2014 [Member] | Overseas General Insurance - Non-Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 1,693 | 1,698 | 1,706 | 1,712 | 1,719 | 1,729 | 1,763 | 1,775 | 1,828 | 1,764
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 3 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 1,680 | 1,678 | 1,684 | 1,677 | 1,662 | 1,649 | 1,619 | 1,560 | 1,359 | 721
Cumulative Number of Reported Claims | 533,000 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Accident Year 2014 [Member] | Global Reinsurance - Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 326 | 326 | 327 | 327 | 344 | 340 | 339 | 336 | 331 | 330
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 6 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 304 | 298 | 293 | 284 | 274 | 263 | 247 | 216 | 183 | 91
Short-duration Insurance Contracts, Accident Year 2014 [Member] | Global Reinsurance - Non-Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | 169 | 169 | 170 | 172 | 173 | 174 | 176 | 173 | 174 | 158
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 1 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 166 | 166 | 165 | 165 | 163 | 161 | 156 | 146 | 124 | $ 63
Short-duration Insurance Contracts, Accident Year 2015 [Member] | North America Commercial P&C Insurance - Workers' Compensation [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | 1,057 | 1,092 | 1,128 | 1,154 | 1,217 | 1,279 | 1,276 | 1,259 | 1,282 |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 286 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 665 | 645 | 628 | 606 | 564 | 501 | 418 | 301 | 116 |
Cumulative Number of Reported Claims | 50,000 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Accident Year 2015 [Member] | North America Commercial P&C Insurance - Liability [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 3,613 | 3,569 | 3,701 | 3,727 | 3,934 | 3,967 | 3,810 | 3,701 | 3,552 |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 358 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 3,079 | 2,921 | 2,743 | 2,527 | 2,287 | 1,852 | 1,203 | 604 | 138 |
Cumulative Number of Reported Claims | 27,000 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Accident Year 2015 [Member] | North America Commercial P&C Insurance - Other Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 456 | 457 | 462 | 454 | 457 | 514 | 500 | 469 | 486 |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 18 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 431 | 423 | 411 | 394 | 370 | 304 | 214 | 137 | 47 |
Cumulative Number of Reported Claims | 15,000 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Accident Year 2015 [Member] | North America Commercial P&C Insurance - Non-Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 1,589 | 1,592 | 1,587 | 1,585 | 1,600 | 1,633 | 1,645 | 1,740 | 1,731 |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 2 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 1,583 | 1,582 | 1,583 | 1,570 | 1,567 | 1,552 | 1,484 | 1,339 | 724 |
Cumulative Number of Reported Claims | 545,000 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Accident Year 2015 [Member] | North America Personal P&C Insurance [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 2,558 | 2,561 | 2,559 | 2,562 | 2,556 | 2,536 | 2,553 | 2,543 | 2,488 |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 5 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 2,542 | 2,535 | 2,526 | 2,501 | 2,472 | 2,385 | 2,264 | 2,078 | 1,495 |
Cumulative Number of Reported Claims | 148,000 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Accident Year 2015 [Member] | Overseas General Insurance - Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 1,186 | 1,187 | 1,171 | 1,186 | 1,244 | 1,262 | 1,239 | 1,209 | 1,118 |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 97 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 969 | 938 | 906 | 830 | 753 | 637 | 465 | 267 | 80 |
Cumulative Number of Reported Claims | 40,000 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Accident Year 2015 [Member] | Overseas General Insurance - Non-Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 1,870 | 1,875 | 1,874 | 1,892 | 1,900 | 1,916 | 1,947 | 1,973 | 1,855 |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 8 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 1,839 | 1,839 | 1,836 | 1,819 | 1,790 | 1,769 | 1,691 | 1,469 | 812 |
Cumulative Number of Reported Claims | 556,000 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Accident Year 2015 [Member] | Global Reinsurance - Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 307 | 308 | 305 | 301 | 305 | 297 | 296 | 286 | 281 |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 9 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 281 | 273 | 264 | 247 | 230 | 215 | 190 | 158 | 89 |
Short-duration Insurance Contracts, Accident Year 2015 [Member] | Global Reinsurance - Non-Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | 154 | 154 | 154 | 156 | 151 | 158 | 158 | 152 | 144 |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 1 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 151 | 150 | 150 | 148 | 144 | 140 | 130 | 102 | $ 56 |
Short-duration Insurance Contracts, Accident Year 2016 [Member] | North America Commercial P&C Insurance - Workers' Compensation [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | 1,162 | 1,177 | 1,206 | 1,269 | 1,378 | 1,383 | 1,361 | 1,366 |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 354 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 683 | 653 | 621 | 584 | 529 | 452 | 326 | 122 |  |
Cumulative Number of Reported Claims | 51,000 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Accident Year 2016 [Member] | North America Commercial P&C Insurance - Liability [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 3,660 | 3,756 | 3,765 | 3,793 | 3,797 | 3,685 | 3,588 | 3,527 |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 375 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 2,982 | 2,820 | 2,593 | 2,332 | 1,973 | 1,334 | 662 | 171 |  |
Cumulative Number of Reported Claims | 27,000 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Accident Year 2016 [Member] | North America Commercial P&C Insurance - Other Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 473 | 469 | 479 | 480 | 523 | 527 | 501 | 503 |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 20 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 437 | 424 | 398 | 374 | 323 | 246 | 145 | 52 |  |
Cumulative Number of Reported Claims | 16,000 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Accident Year 2016 [Member] | North America Commercial P&C Insurance - Non-Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 1,822 | 1,820 | 1,824 | 1,811 | 1,775 | 1,794 | 1,884 | 1,904 |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 23 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 1,790 | 1,789 | 1,778 | 1,754 | 1,726 | 1,650 | 1,499 | 844 |  |
Cumulative Number of Reported Claims | 650,000 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Accident Year 2016 [Member] | North America Personal P&C Insurance [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 2,467 | 2,466 | 2,458 | 2,464 | 2,476 | 2,538 | 2,529 | 2,433 |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 10 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 2,440 | 2,422 | 2,391 | 2,364 | 2,308 | 2,205 | 2,046 | 1,449 |  |
Cumulative Number of Reported Claims | 154,000 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Accident Year 2016 [Member] | Overseas General Insurance - Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 1,283 | 1,271 | 1,337 | 1,328 | 1,338 | 1,311 | 1,246 | 1,150 |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 93 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 1,003 | 979 | 857 | 766 | 648 | 505 | 306 | 120 |  |
Cumulative Number of Reported Claims | 42,000 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Accident Year 2016 [Member] | Overseas General Insurance - Non-Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 1,943 | 1,955 | 1,957 | 1,926 | 1,921 | 1,942 | 1,955 | 1,959 |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 29 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 1,890 | 1,887 | 1,881 | 1,872 | 1,847 | 1,779 | 1,592 | 966 |  |
Cumulative Number of Reported Claims | 568,000 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Accident Year 2016 [Member] | Global Reinsurance - Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 250 | 244 | 239 | 239 | 230 | 231 | 223 | 219 |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 11 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 217 | 206 | 190 | 173 | 157 | 141 | 112 | 57 |  |
Short-duration Insurance Contracts, Accident Year 2016 [Member] | Global Reinsurance - Non-Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | 181 | 181 | 181 | 184 | 187 | 185 | 182 | 177 |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 1 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 177 | 176 | 175 | 172 | 166 | 156 | 129 | $ 56 |  |
Short-duration Insurance Contracts, Accident Year 2017 [Member] | North America Commercial P&C Insurance - Workers' Compensation [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | 1,121 | 1,176 | 1,376 | 1,393 | 1,399 | 1,380 | 1,412 |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 402 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 626 | 601 | 564 | 516 | 437 | 313 | 120 |  |  |
Cumulative Number of Reported Claims | 50,000 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Accident Year 2017 [Member] | North America Commercial P&C Insurance - Liability [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 3,492 | 3,434 | 3,545 | 3,623 | 3,573 | 3,491 | 3,316 |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 603 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 2,627 | 2,322 | 2,000 | 1,698 | 1,160 | 616 | 161 |  |  |
Cumulative Number of Reported Claims | 26,000 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Accident Year 2017 [Member] | North America Commercial P&C Insurance - Other Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 602 | 590 | 604 | 616 | 577 | 565 | 531 |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 16 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 539 | 496 | 446 | 381 | 312 | 175 | 66 |  |  |
Cumulative Number of Reported Claims | 17,000 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Accident Year 2017 [Member] | North America Commercial P&C Insurance - Non-Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 2,508 | 2,522 | 2,512 | 2,520 | 2,503 | 2,603 | 2,699 |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 43 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 2,449 | 2,430 | 2,406 | 2,392 | 2,301 | 2,083 | 977 |  |  |
Cumulative Number of Reported Claims | 764,000 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Accident Year 2017 [Member] | North America Personal P&C Insurance [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 3,011 | 3,001 | 2,992 | 2,991 | 2,995 | 3,062 | 3,028 |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 20 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 2,971 | 2,930 | 2,864 | 2,793 | 2,662 | 2,514 | 1,694 |  |  |
Cumulative Number of Reported Claims | 163,000 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Accident Year 2017 [Member] | Overseas General Insurance - Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 1,296 | 1,331 | 1,296 | 1,331 | 1,284 | 1,237 | 1,140 |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 151 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 995 | 940 | 812 | 653 | 499 | 299 | 91 |  |  |
Cumulative Number of Reported Claims | 43,000 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Accident Year 2017 [Member] | Overseas General Insurance - Non-Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 2,115 | 2,149 | 2,151 | 2,126 | 2,145 | 2,157 | 2,114 |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | (6) |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 2,091 | 2,114 | 2,055 | 2,013 | 1,940 | 1,772 | 1,010 |  |  |
Cumulative Number of Reported Claims | 577,000 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Accident Year 2017 [Member] | Global Reinsurance - Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 221 | 214 | 214 | 213 | 216 | 211 | 209 |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 6 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 185 | 173 | 153 | 138 | 120 | 99 | 46 |  |  |
Short-duration Insurance Contracts, Accident Year 2017 [Member] | Global Reinsurance - Non-Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | 454 | 455 | 453 | 449 | 451 | 421 | 395 |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 7 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 439 | 433 | 426 | 413 | 400 | 321 | $ 191 |  |  |
Short-duration Insurance Contracts, Accident Year 2018 [Member] | North America Commercial P&C Insurance - Workers' Compensation [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | 1,221 | 1,384 | 1,385 | 1,380 | 1,361 | 1,359 |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 435 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 641 | 597 | 528 | 451 | 329 | 130 |  |  |  |
Cumulative Number of Reported Claims | 51,000 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Accident Year 2018 [Member] | North America Commercial P&C Insurance - Liability [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 3,915 | 3,900 | 3,820 | 3,688 | 3,485 | 3,368 |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 672 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 2,782 | 2,335 | 1,773 | 1,301 | 753 | 189 |  |  |  |
Cumulative Number of Reported Claims | 28,000 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Accident Year 2018 [Member] | North America Commercial P&C Insurance - Other Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 606 | 575 | 579 | 574 | 563 | 535 |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 9 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 532 | 472 | 365 | 270 | 169 | 74 |  |  |  |
Cumulative Number of Reported Claims | 17,000 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Accident Year 2018 [Member] | North America Commercial P&C Insurance - Non-Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 2,160 | 2,170 | 2,161 | 2,169 | 2,234 | 2,047 |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 11 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 2,137 | 2,113 | 2,068 | 2,012 | 1,821 | 1,025 |  |  |  |
Cumulative Number of Reported Claims | 904,000 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Accident Year 2018 [Member] | North America Personal P&C Insurance [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 3,120 | 3,131 | 3,110 | 3,095 | 3,030 | 3,002 |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 45 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 3,037 | 2,971 | 2,857 | 2,699 | 2,542 | 1,922 |  |  |  |
Cumulative Number of Reported Claims | 170,000 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Accident Year 2018 [Member] | Overseas General Insurance - Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 1,323 | 1,345 | 1,389 | 1,346 | 1,286 | 1,236 |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 202 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 881 | 727 | 608 | 470 | 312 | 105 |  |  |  |
Cumulative Number of Reported Claims | 44,000 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Accident Year 2018 [Member] | Overseas General Insurance - Non-Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 2,051 | 2,062 | 2,093 | 2,119 | 2,156 | 2,068 |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 42 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 1,950 | 1,940 | 1,924 | 1,858 | 1,664 | 960 |  |  |  |
Cumulative Number of Reported Claims | 613,000 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Accident Year 2018 [Member] | Global Reinsurance - Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 255 | 248 | 245 | 249 | 242 | 239 |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 9 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 194 | 168 | 146 | 123 | 94 | 40 |  |  |  |
Short-duration Insurance Contracts, Accident Year 2018 [Member] | Global Reinsurance - Non-Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | 282 | 289 | 284 | 288 | 286 | 278 |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 2 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 274 | 272 | 267 | 264 | 248 | $ 94 |  |  |  |
Short-Duration Insurance Contract, Accident Year 2019 [Member] | North America Commercial P&C Insurance - Workers' Compensation [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | 1,406 | 1,409 | 1,400 | 1,384 | 1,391 |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 611 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 640 | 575 | 467 | 341 | 143 |  |  |  |  |
Cumulative Number of Reported Claims | 48,000 |  |  |  |  |  |  |  |  |
Short-Duration Insurance Contract, Accident Year 2019 [Member] | North America Commercial P&C Insurance - Liability [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 4,057 | 4,050 | 3,858 | 3,620 | 3,446 |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 1,135 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 2,387 | 1,888 | 1,245 | 669 | 175 |  |  |  |  |
Cumulative Number of Reported Claims | 29,000 |  |  |  |  |  |  |  |  |
Short-Duration Insurance Contract, Accident Year 2019 [Member] | North America Commercial P&C Insurance - Other Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 756 | 744 | 686 | 636 | 606 |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 40 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 619 | 465 | 318 | 189 | 70 |  |  |  |  |
Cumulative Number of Reported Claims | 17,000 |  |  |  |  |  |  |  |  |
Short-Duration Insurance Contract, Accident Year 2019 [Member] | North America Commercial P&C Insurance - Non-Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 1,921 | 1,944 | 1,954 | 2,031 | 2,046 |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 13 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 1,883 | 1,856 | 1,800 | 1,672 | 1,028 |  |  |  |  |
Cumulative Number of Reported Claims | 1,044,000 |  |  |  |  |  |  |  |  |
Short-Duration Insurance Contract, Accident Year 2019 [Member] | North America Personal P&C Insurance [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 2,957 | 2,978 | 2,986 | 2,985 | 2,949 |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 48 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 2,823 | 2,718 | 2,611 | 2,431 | 1,664 |  |  |  |  |
Cumulative Number of Reported Claims | 157,000 |  |  |  |  |  |  |  |  |
Short-Duration Insurance Contract, Accident Year 2019 [Member] | Overseas General Insurance - Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 1,336 | 1,382 | 1,395 | 1,373 | 1,307 |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 311 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 729 | 648 | 444 | 316 | 118 |  |  |  |  |
Cumulative Number of Reported Claims | 42,000 |  |  |  |  |  |  |  |  |
Short-Duration Insurance Contract, Accident Year 2019 [Member] | Overseas General Insurance - Non-Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 2,043 | 2,047 | 2,059 | 2,119 | 2,100 |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | (12) |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 1,959 | 1,926 | 1,861 | 1,674 | 1,019 |  |  |  |  |
Cumulative Number of Reported Claims | 632,000 |  |  |  |  |  |  |  |  |
Short-Duration Insurance Contract, Accident Year 2019 [Member] | Global Reinsurance - Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 233 | 236 | 237 | 242 | 233 |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 20 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 161 | 138 | 115 | 89 | 39 |  |  |  |  |
Short-Duration Insurance Contract, Accident Year 2019 [Member] | Global Reinsurance - Non-Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | 116 | 120 | 125 | 129 | 130 |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 3 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 104 | 102 | 94 | 80 | $ 35 |  |  |  |  |
Short-Duration Insurance Contract, Accident Year 2020 | North America Commercial P&C Insurance - Workers' Compensation [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | 1,408 | 1,409 | 1,388 | 1,367 |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 756 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 466 | 390 | 282 | 111 |  |  |  |  |  |
Cumulative Number of Reported Claims | 31,000 |  |  |  |  |  |  |  |  |
Short-Duration Insurance Contract, Accident Year 2020 | North America Commercial P&C Insurance - Liability [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 3,976 | 3,919 | 3,826 | 4,102 |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 1,630 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 1,697 | 1,148 | 589 | 152 |  |  |  |  |  |
Cumulative Number of Reported Claims | 24,000 |  |  |  |  |  |  |  |  |
Short-Duration Insurance Contract, Accident Year 2020 | North America Commercial P&C Insurance - Other Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 638 | 657 | 633 | 640 |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 156 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 401 | 273 | 156 | 54 |  |  |  |  |  |
Cumulative Number of Reported Claims | 11,000 |  |  |  |  |  |  |  |  |
Short-Duration Insurance Contract, Accident Year 2020 | North America Commercial P&C Insurance - Non-Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 2,685 | 2,726 | 2,942 | 3,140 |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 62 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 2,545 | 2,466 | 2,260 | 1,390 |  |  |  |  |  |
Cumulative Number of Reported Claims | 1,126,000 |  |  |  |  |  |  |  |  |
Short-Duration Insurance Contract, Accident Year 2020 | North America Personal P&C Insurance [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 2,582 | 2,626 | 2,627 | 2,922 |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 96 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 2,363 | 2,223 | 1,990 | 1,331 |  |  |  |  |  |
Cumulative Number of Reported Claims | 123,000 |  |  |  |  |  |  |  |  |
Short-Duration Insurance Contract, Accident Year 2020 | Overseas General Insurance - Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 1,535 | 1,523 | 1,606 | 1,684 |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 765 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 530 | 429 | 273 | 102 |  |  |  |  |  |
Cumulative Number of Reported Claims | 35,000 |  |  |  |  |  |  |  |  |
Short-Duration Insurance Contract, Accident Year 2020 | Overseas General Insurance - Non-Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 2,116 | 2,171 | 2,301 | 2,437 |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 87 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 1,908 | 1,792 | 1,646 | 1,036 |  |  |  |  |  |
Cumulative Number of Reported Claims | 534,000 |  |  |  |  |  |  |  |  |
Short-Duration Insurance Contract, Accident Year 2020 | Global Reinsurance - Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 237 | 237 | 246 | 242 |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 42 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 147 | 123 | 98 | 41 |  |  |  |  |  |
Short-Duration Insurance Contract, Accident Year 2020 | Global Reinsurance - Non-Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | 279 | 277 | 253 | 209 |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 22 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 232 | 215 | 177 | $ 62 |  |  |  |  |  |
Short-Duration Insurance Contract, Accident Year 2021 | North America Commercial P&C Insurance - Workers' Compensation [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | 1,372 | 1,330 | 1,348 |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 708 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 458 | 331 | 120 |  |  |  |  |  |  |
Cumulative Number of Reported Claims | 35,000 |  |  |  |  |  |  |  |  |
Short-Duration Insurance Contract, Accident Year 2021 | North America Commercial P&C Insurance - Liability [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 4,441 | 4,349 | 4,315 |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 2,589 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 1,200 | 609 | 174 |  |  |  |  |  |  |
Cumulative Number of Reported Claims | 25,000 |  |  |  |  |  |  |  |  |
Short-Duration Insurance Contract, Accident Year 2021 | North America Commercial P&C Insurance - Other Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 747 | 710 | 675 |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 254 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 293 | 176 | 60 |  |  |  |  |  |  |
Cumulative Number of Reported Claims | 13,000 |  |  |  |  |  |  |  |  |
Short-Duration Insurance Contract, Accident Year 2021 | North America Commercial P&C Insurance - Non-Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 2,628 | 2,824 | 2,941 |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 158 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 2,322 | 2,100 | 1,085 |  |  |  |  |  |  |
Cumulative Number of Reported Claims | 863,000 |  |  |  |  |  |  |  |  |
Short-Duration Insurance Contract, Accident Year 2021 | North America Personal P&C Insurance [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 2,964 | 2,877 | 3,027 |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 209 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 2,582 | 2,368 | 1,583 |  |  |  |  |  |  |
Cumulative Number of Reported Claims | 131,000 |  |  |  |  |  |  |  |  |
Short-Duration Insurance Contract, Accident Year 2021 | Overseas General Insurance - Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 1,691 | 1,668 | 1,619 |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 987 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 434 | 271 | 111 |  |  |  |  |  |  |
Cumulative Number of Reported Claims | 36,000 |  |  |  |  |  |  |  |  |
Short-Duration Insurance Contract, Accident Year 2021 | Overseas General Insurance - Non-Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 2,322 | 2,437 | 2,524 |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 60 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 2,025 | 1,750 | 982 |  |  |  |  |  |  |
Cumulative Number of Reported Claims | 542,000 |  |  |  |  |  |  |  |  |
Short-Duration Insurance Contract, Accident Year 2021 | Global Reinsurance - Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 286 | 282 | 278 |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 105 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 119 | 86 | 35 |  |  |  |  |  |  |
Short-Duration Insurance Contract, Accident Year 2021 | Global Reinsurance - Non-Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | 354 | 351 | 340 |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 23 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 307 | 277 | $ 158 |  |  |  |  |  |  |
Short-Duration Insurance Contract, Accident Year 2022 | North America Commercial P&C Insurance - Workers' Compensation [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | 1,407 | 1,344 |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 835 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 332 | 131 |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | 38,000 |  |  |  |  |  |  |  |  |
Short-Duration Insurance Contract, Accident Year 2022 | North America Commercial P&C Insurance - Liability [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 4,567 | 4,561 |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 3,371 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 649 | 144 |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | 25,000 |  |  |  |  |  |  |  |  |
Short-Duration Insurance Contract, Accident Year 2022 | North America Commercial P&C Insurance - Other Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 801 | 782 |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 367 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 235 | 82 |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | 14,000 |  |  |  |  |  |  |  |  |
Short-Duration Insurance Contract, Accident Year 2022 | North America Commercial P&C Insurance - Non-Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 2,946 | 3,048 |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 371 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 2,190 | 1,050 |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | 897,000 |  |  |  |  |  |  |  |  |
Short-Duration Insurance Contract, Accident Year 2022 | North America Personal P&C Insurance [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 2,955 | 3,102 |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 414 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 2,278 | 1,411 |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | 119,000 |  |  |  |  |  |  |  |  |
Short-Duration Insurance Contract, Accident Year 2022 | Overseas General Insurance - Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 1,808 | 1,760 |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 1,217 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 284 | 83 |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | 36,000 |  |  |  |  |  |  |  |  |
Short-Duration Insurance Contract, Accident Year 2022 | Overseas General Insurance - Non-Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 2,777 | 2,800 |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 168 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 2,088 | 1,168 |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | 614,000 |  |  |  |  |  |  |  |  |
Short-Duration Insurance Contract, Accident Year 2022 | Global Reinsurance - Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 296 | 294 |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 155 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 86 | 39 |  |  |  |  |  |  |  |
Short-Duration Insurance Contract, Accident Year 2022 | Global Reinsurance - Non-Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | 311 | 346 |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 69 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 195 | $ 74 |  |  |  |  |  |  |  |
Short-Duration Insurance Contract, Accident Year 2023 | North America Commercial P&C Insurance - Workers' Compensation [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | 1,371 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 992 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 129 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | 33,000 |  |  |  |  |  |  |  |  |
Short-Duration Insurance Contract, Accident Year 2023 | North America Commercial P&C Insurance - Liability [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 4,703 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 4,181 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 197 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | 26,000 |  |  |  |  |  |  |  |  |
Short-Duration Insurance Contract, Accident Year 2023 | North America Commercial P&C Insurance - Other Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 844 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 631 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 81 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | 11,000 |  |  |  |  |  |  |  |  |
Short-Duration Insurance Contract, Accident Year 2023 | North America Commercial P&C Insurance - Non-Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 3,072 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 1,351 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 1,219 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | 756,000 |  |  |  |  |  |  |  |  |
Short-Duration Insurance Contract, Accident Year 2023 | North America Personal P&C Insurance [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 3,406 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 1,480 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 1,490 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | 93,000 |  |  |  |  |  |  |  |  |
Short-Duration Insurance Contract, Accident Year 2023 | Overseas General Insurance - Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 1,908 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 1,606 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 79 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | 32,000 |  |  |  |  |  |  |  |  |
Short-Duration Insurance Contract, Accident Year 2023 | Overseas General Insurance - Non-Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 2,995 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 901 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 1,119 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | 594,000 |  |  |  |  |  |  |  |  |
Short-Duration Insurance Contract, Accident Year 2023 | Global Reinsurance - Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | $ 274 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 211 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 30 |  |  |  |  |  |  |  |  |
Short-Duration Insurance Contract, Accident Year 2023 | Global Reinsurance - Non-Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net | 181 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | 109 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 36 |  |  |  |  |  |  |  |  |
Accident years prior to 2014 | North America Commercial P&C Insurance - Workers' Compensation [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented | 2,940 |  |  |  |  |  |  |  |  |
Accident years prior to 2014 | North America Commercial P&C Insurance - Liability [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented | 1,936 |  |  |  |  |  |  |  |  |
Accident years prior to 2014 | North America Commercial P&C Insurance - Other Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented | 228 |  |  |  |  |  |  |  |  |
Accident years prior to 2014 | North America Commercial P&C Insurance - Non-Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented | (13) |  |  |  |  |  |  |  |  |
Accident years prior to 2014 | North America Personal P&C Insurance [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented | 47 |  |  |  |  |  |  |  |  |
Accident years prior to 2014 | Overseas General Insurance - Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented | 540 |  |  |  |  |  |  |  |  |
Accident years prior to 2014 | Overseas General Insurance - Non-Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented | 139 |  |  |  |  |  |  |  |  |
Accident years prior to 2014 | Global Reinsurance - Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented | 279 |  |  |  |  |  |  |  |  |
Accident years prior to 2014 | Global Reinsurance - Non-Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented | 11 |  |  |  |  |  |  |  |  |
Accident years 2014 - 2023 | North America Commercial P&C Insurance - Workers' Compensation [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented | 7,219 |  |  |  |  |  |  |  |  |
Accident years 2014 - 2023 | North America Commercial P&C Insurance - Liability [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented | 19,156 |  |  |  |  |  |  |  |  |
Accident years 2014 - 2023 | North America Commercial P&C Insurance - Other Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented | 2,368 |  |  |  |  |  |  |  |  |
Accident years 2014 - 2023 | North America Commercial P&C Insurance - Non-Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented | 3,216 |  |  |  |  |  |  |  |  |
Accident years 2014 - 2023 | North America Personal P&C Insurance [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented | 3,503 |  |  |  |  |  |  |  |  |
Accident years 2014 - 2023 | Overseas General Insurance - Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented | 7,617 |  |  |  |  |  |  |  |  |
Accident years 2014 - 2023 | Overseas General Insurance - Non-Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented | 3,376 |  |  |  |  |  |  |  |  |
Accident years 2014 - 2023 | Global Reinsurance - Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented | 961 |  |  |  |  |  |  |  |  |
Accident years 2014 - 2023 | Global Reinsurance - Non-Casualty [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented | $ 400 |  |  |  |  |  |  |  |  |

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