XML 81 R66.htm IDEA: XBRL DOCUMENT
v3.22.4

Short Duration Contracts - Claims development - Reinsurance (Details) - USD ($) $ in Thousands | Dec. 31, 2022 | Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | Dec. 31, 2014 | Dec. 31, 2013
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Liabilities for losses and loss adjustment expenses, net of reinsurance | $ 13,445,271 |  |  |  |  |  |  |  |  |
Reinsurance | Casualty |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 3,179,551 |  |  |  |  |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 1,155,014 |  |  |  |  |  |  |  |  |
All outstanding liabilities before 2013, net of reinsurance | 299,288 |  |  |  |  |  |  |  |  |
Liabilities for losses and loss adjustment expenses, net of reinsurance | 2,323,825 |  |  |  |  |  |  |  |  |
Reinsurance | Casualty | 2013 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 133,094 | $ 133,687 | $ 133,401 | $ 129,120 | $ 132,701 | $ 134,204 | $ 146,230 | $ 152,392 | $ 156,619 | $ 163,425
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 87,485 | 81,167 | 76,141 | 70,289 | 62,751 | 54,323 | 42,861 | 22,886 | 9,822 | 2,421
Total of IBNR liabilities plus expected development on reported claims | 26,542 |  |  |  |  |  |  |  |  |
Reinsurance | Casualty | 2014 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 231,175 | 230,944 | 234,293 | 233,922 | 224,105 | 227,485 | 214,724 | 217,991 | 212,923 |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 152,586 | 143,929 | 133,263 | 113,596 | 90,530 | 63,214 | 40,651 | 15,973 | 3,885 |
Total of IBNR liabilities plus expected development on reported claims | 33,255 |  |  |  |  |  |  |  |  |
Reinsurance | Casualty | 2015 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 247,419 | 245,756 | 242,554 | 235,637 | 231,473 | 224,385 | 216,759 | 217,343 |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 151,119 | 136,138 | 119,096 | 95,988 | 70,523 | 46,933 | 20,208 | 4,440 |  |
Total of IBNR liabilities plus expected development on reported claims | 44,753 |  |  |  |  |  |  |  |  |
Reinsurance | Casualty | 2016 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 268,079 | 264,475 | 264,573 | 257,214 | 242,089 | 221,004 | 208,192 |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 155,584 | 131,341 | 112,818 | 86,362 | 51,494 | 25,626 | 5,720 |  |  |
Total of IBNR liabilities plus expected development on reported claims | 46,122 |  |  |  |  |  |  |  |  |
Reinsurance | Casualty | 2017 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 310,858 | 304,194 | 293,381 | 267,173 | 251,827 | 262,894 |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 163,243 | 136,489 | 112,474 | 63,922 | 30,316 | 6,417 |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | 52,415 |  |  |  |  |  |  |  |  |
Reinsurance | Casualty | 2018 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 293,320 | 281,852 | 276,802 | 284,405 | 270,621 |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 154,173 | 128,728 | 106,443 | 31,240 | 7,576 |  |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | 56,325 |  |  |  |  |  |  |  |  |
Reinsurance | Casualty | 2019 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 372,669 | 361,549 | 334,755 | 325,359 |  |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 129,766 | 96,593 | 57,568 | 15,798 |  |  |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | 93,310 |  |  |  |  |  |  |  |  |
Reinsurance | Casualty | 2020 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 349,831 | 367,595 | 378,668 |  |  |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 90,156 | 50,383 | 17,646 |  |  |  |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | 169,909 |  |  |  |  |  |  |  |  |
Reinsurance | Casualty | 2021 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 431,165 | 434,187 |  |  |  |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 53,264 | 14,633 |  |  |  |  |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | 292,696 |  |  |  |  |  |  |  |  |
Reinsurance | Casualty | 2022 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 541,941 |  |  |  |  |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 17,638 |  |  |  |  |  |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | 482,552 |  |  |  |  |  |  |  |  |
Reinsurance | Property catastrophe |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 1,017,376 |  |  |  |  |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 484,830 |  |  |  |  |  |  |  |  |
All outstanding liabilities before 2013, net of reinsurance | 2,612 |  |  |  |  |  |  |  |  |
Liabilities for losses and loss adjustment expenses, net of reinsurance | 535,158 |  |  |  |  |  |  |  |  |
Reinsurance | Property catastrophe | 2013 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 26,221 | 26,344 | 26,543 | 26,415 | 27,248 | 27,974 | 30,518 | 34,959 | 45,962 | 65,372
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 27,023 | 26,998 | 27,233 | 26,549 | 26,549 | 26,329 | 24,697 | 23,001 | 18,496 | 12,035
Total of IBNR liabilities plus expected development on reported claims | (138) |  |  |  |  |  |  |  |  |
Reinsurance | Property catastrophe | 2014 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 19,045 | 19,004 | 19,229 | 19,326 | 20,026 | 21,764 | 24,500 | 29,801 | 43,800 |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 18,592 | 18,629 | 18,550 | 18,421 | 18,244 | 18,679 | 17,902 | 19,544 | 13,619 |
Total of IBNR liabilities plus expected development on reported claims | (10) |  |  |  |  |  |  |  |  |
Reinsurance | Property catastrophe | 2015 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 2,569 | 2,932 | 3,133 | 3,779 | 5,531 | 11,425 | 17,558 | 32,748 |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 1,874 | 1,817 | 1,745 | 1,659 | 2,103 | 1,843 | (2,109) | (3,141) |  |
Total of IBNR liabilities plus expected development on reported claims | 68 |  |  |  |  |  |  |  |  |
Reinsurance | Property catastrophe | 2016 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 5,181 | 5,987 | 6,886 | 9,190 | 12,749 | 16,582 | 23,224 |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 2,594 | 2,433 | 2,086 | 2,932 | 1,870 | 1,759 | (7,039) |  |  |
Total of IBNR liabilities plus expected development on reported claims | 877 |  |  |  |  |  |  |  |  |
Reinsurance | Property catastrophe | 2017 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 21,026 | 24,239 | 35,893 | 49,507 | 53,699 | 86,410 |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 16,034 | 14,215 | 27,060 | 37,084 | 31,621 | 30,625 |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | (803) |  |  |  |  |  |  |  |  |
Reinsurance | Property catastrophe | 2018 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 10,722 | 19,831 | 33,425 | 52,001 | 73,041 |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | (8,100) | (10,934) | 18,253 | 7,344 | 27,424 |  |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | 3,039 |  |  |  |  |  |  |  |  |
Reinsurance | Property catastrophe | 2019 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 4,590 | 13,093 | 14,252 | 25,526 |  |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | (11,472) | 12,895 | 8,845 | 4,374 |  |  |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | 4,576 |  |  |  |  |  |  |  |  |
Reinsurance | Property catastrophe | 2020 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 326,262 | 322,680 | 260,244 |  |  |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 200,510 | 152,075 | 52,592 |  |  |  |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | 33,413 |  |  |  |  |  |  |  |  |
Reinsurance | Property catastrophe | 2021 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 302,124 | 308,014 |  |  |  |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 167,806 | 64,408 |  |  |  |  |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | 29,963 |  |  |  |  |  |  |  |  |
Reinsurance | Property catastrophe | 2022 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 299,636 |  |  |  |  |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 69,969 |  |  |  |  |  |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | 73,474 |  |  |  |  |  |  |  |  |
Reinsurance | Property excluding property catastrophe |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 2,592,090 |  |  |  |  |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 1,587,251 |  |  |  |  |  |  |  |  |
All outstanding liabilities before 2013, net of reinsurance | 5,765 |  |  |  |  |  |  |  |  |
Liabilities for losses and loss adjustment expenses, net of reinsurance | 1,010,604 |  |  |  |  |  |  |  |  |
Reinsurance | Property excluding property catastrophe | 2013 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 63,390 | 62,288 | 62,774 | 62,070 | 63,247 | 64,013 | 65,734 | 69,981 | 76,290 | 114,775
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 63,228 | 61,665 | 61,640 | 60,777 | 55,272 | 53,400 | 52,614 | 49,433 | 42,418 | 25,943
Total of IBNR liabilities plus expected development on reported claims | 29 |  |  |  |  |  |  |  |  |
Reinsurance | Property excluding property catastrophe | 2014 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 79,307 | 80,348 | 81,812 | 83,476 | 87,768 | 90,031 | 98,263 | 116,331 | 142,092 |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 77,894 | 77,728 | 78,029 | 78,067 | 77,687 | 76,060 | 71,144 | 62,414 | 23,342 |
Total of IBNR liabilities plus expected development on reported claims | 443 |  |  |  |  |  |  |  |  |
Reinsurance | Property excluding property catastrophe | 2015 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 166,580 | 172,189 | 175,812 | 186,861 | 187,569 | 183,709 | 187,932 | 213,681 |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 159,054 | 158,537 | 158,293 | 164,637 | 159,482 | 148,887 | 118,396 | 75,458 |  |
Total of IBNR liabilities plus expected development on reported claims | 3,909 |  |  |  |  |  |  |  |  |
Reinsurance | Property excluding property catastrophe | 2016 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 128,941 | 135,116 | 138,216 | 134,362 | 136,367 | 144,323 | 174,506 |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 114,432 | 113,300 | 111,039 | 103,202 | 97,918 | 94,121 | 33,236 |  |  |
Total of IBNR liabilities plus expected development on reported claims | 6,208 |  |  |  |  |  |  |  |  |
Reinsurance | Property excluding property catastrophe | 2017 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 204,128 | 212,133 | 227,891 | 235,310 | 247,462 | 266,628 |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 181,029 | 177,737 | 162,933 | 155,139 | 124,220 | 27,456 |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | 8,794 |  |  |  |  |  |  |  |  |
Reinsurance | Property excluding property catastrophe | 2018 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 201,429 | 211,852 | 234,794 | 238,876 | 222,932 |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 174,778 | 166,598 | 151,632 | 107,172 | 29,654 |  |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | 7,370 |  |  |  |  |  |  |  |  |
Reinsurance | Property excluding property catastrophe | 2019 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 189,456 | 194,164 | 204,620 | 214,513 |  |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 161,573 | 149,377 | 123,293 | 42,919 |  |  |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | 8,407 |  |  |  |  |  |  |  |  |
Reinsurance | Property excluding property catastrophe | 2020 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 319,097 | 338,712 | 366,726 |  |  |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 242,844 | 207,061 | 100,927 |  |  |  |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | 36,912 |  |  |  |  |  |  |  |  |
Reinsurance | Property excluding property catastrophe | 2021 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 497,059 | 545,101 |  |  |  |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 269,481 | 135,815 |  |  |  |  |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | 83,934 |  |  |  |  |  |  |  |  |
Reinsurance | Property excluding property catastrophe | 2022 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 742,703 |  |  |  |  |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 142,938 |  |  |  |  |  |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | 360,528 |  |  |  |  |  |  |  |  |
Reinsurance | Marine and aviation |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 480,791 |  |  |  |  |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 208,846 |  |  |  |  |  |  |  |  |
All outstanding liabilities before 2013, net of reinsurance | 17,999 |  |  |  |  |  |  |  |  |
Liabilities for losses and loss adjustment expenses, net of reinsurance | 289,944 |  |  |  |  |  |  |  |  |
Reinsurance | Marine and aviation | 2013 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 25,695 | 26,728 | 29,434 | 33,001 | 33,453 | 34,207 | 34,293 | 35,669 | 36,765 | 38,167
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 23,648 | 22,912 | 22,941 | 23,176 | 22,803 | 21,557 | 20,580 | 17,678 | 13,054 | 4,751
Total of IBNR liabilities plus expected development on reported claims | 1,012 |  |  |  |  |  |  |  |  |
Reinsurance | Marine and aviation | 2014 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 18,511 | 21,651 | 21,698 | 22,919 | 23,302 | 25,297 | 26,995 | 28,757 | 30,566 |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 17,084 | 15,729 | 15,650 | 14,794 | 14,368 | 12,209 | 11,335 | 7,795 | 4,005 |
Total of IBNR liabilities plus expected development on reported claims | 800 |  |  |  |  |  |  |  |  |
Reinsurance | Marine and aviation | 2015 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 25,008 | 27,299 | 28,120 | 30,423 | 31,373 | 31,499 | 37,019 | 33,134 |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 22,297 | 22,114 | 21,971 | 22,318 | 20,623 | 18,852 | 13,321 | (6) |  |
Total of IBNR liabilities plus expected development on reported claims | 1,514 |  |  |  |  |  |  |  |  |
Reinsurance | Marine and aviation | 2016 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 11,952 | 14,896 | 16,834 | 19,122 | 23,448 | 22,625 | 27,258 |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 7,028 | 6,656 | 5,764 | 3,169 | 445 | (1,739) | (7,371) |  |  |
Total of IBNR liabilities plus expected development on reported claims | 4,080 |  |  |  |  |  |  |  |  |
Reinsurance | Marine and aviation | 2017 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 17,329 | 19,842 | 20,749 | 23,613 | 26,165 | 28,590 |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 11,817 | 11,488 | 10,897 | 9,249 | 6,433 | 1,650 |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | 4,178 |  |  |  |  |  |  |  |  |
Reinsurance | Marine and aviation | 2018 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 21,052 | 24,192 | 24,058 | 25,680 | 27,613 |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 13,923 | 13,332 | 11,021 | 6,817 | 1,993 |  |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | 3,738 |  |  |  |  |  |  |  |  |
Reinsurance | Marine and aviation | 2019 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 60,635 | 60,321 | 54,684 | 48,383 |  |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 34,637 | 28,680 | 21,261 | 10,537 |  |  |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | 5,574 |  |  |  |  |  |  |  |  |
Reinsurance | Marine and aviation | 2020 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 79,338 | 75,695 | 82,716 |  |  |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 42,203 | 26,129 | 9,096 |  |  |  |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | 28,621 |  |  |  |  |  |  |  |  |
Reinsurance | Marine and aviation | 2021 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 95,586 | 110,129 |  |  |  |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 24,108 | 8,407 |  |  |  |  |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | 51,391 |  |  |  |  |  |  |  |  |
Reinsurance | Marine and aviation | 2022 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 125,685 |  |  |  |  |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 12,101 |  |  |  |  |  |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | 99,917 |  |  |  |  |  |  |  |  |
Reinsurance | Other specialty |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 4,248,999 |  |  |  |  |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 2,817,079 |  |  |  |  |  |  |  |  |
All outstanding liabilities before 2013, net of reinsurance | 13,001 |  |  |  |  |  |  |  |  |
Liabilities for losses and loss adjustment expenses, net of reinsurance | 1,444,921 |  |  |  |  |  |  |  |  |
Reinsurance | Other specialty | 2013 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 254,380 | 255,453 | 257,960 | 263,713 | 264,418 | 266,970 | 267,106 | 269,105 | 280,398 | 304,905
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 243,881 | 240,669 | 237,559 | 237,023 | 229,228 | 222,292 | 209,775 | 188,651 | 155,936 | $ 81,609
Total of IBNR liabilities plus expected development on reported claims | 4,327 |  |  |  |  |  |  |  |  |
Reinsurance | Other specialty | 2014 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 287,941 | 289,460 | 295,270 | 299,789 | 298,357 | 303,589 | 310,153 | 308,074 | 328,056 |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 271,712 | 270,529 | 266,898 | 263,123 | 250,427 | 240,680 | 223,243 | 181,222 | $ 92,743 |
Total of IBNR liabilities plus expected development on reported claims | 6,034 |  |  |  |  |  |  |  |  |
Reinsurance | Other specialty | 2015 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 248,848 | 250,103 | 261,158 | 263,985 | 263,826 | 267,079 | 269,237 | 271,235 |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 231,384 | 230,640 | 227,879 | 216,683 | 204,444 | 190,699 | 157,176 | $ 80,453 |  |
Total of IBNR liabilities plus expected development on reported claims | 6,340 |  |  |  |  |  |  |  |  |
Reinsurance | Other specialty | 2016 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 293,571 | 296,251 | 301,277 | 295,116 | 303,432 | 310,907 | 313,982 |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 277,028 | 271,609 | 265,763 | 249,699 | 231,761 | 196,496 | $ 103,649 |  |  |
Total of IBNR liabilities plus expected development on reported claims | 8,371 |  |  |  |  |  |  |  |  |
Reinsurance | Other specialty | 2017 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 351,478 | 355,763 | 357,212 | 357,762 | 375,347 | 382,884 |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 322,863 | 312,273 | 299,405 | 285,299 | 245,165 | $ 130,150 |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | 22,234 |  |  |  |  |  |  |  |  |
Reinsurance | Other specialty | 2018 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 408,905 | 413,116 | 390,135 | 395,484 | 402,372 |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 340,061 | 323,868 | 303,141 | 265,000 | $ 124,996 |  |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | 32,668 |  |  |  |  |  |  |  |  |
Reinsurance | Other specialty | 2019 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 383,491 | 387,810 | 393,864 | 414,049 |  |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 293,260 | 267,972 | 204,625 | $ 116,762 |  |  |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | 38,889 |  |  |  |  |  |  |  |  |
Reinsurance | Other specialty | 2020 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 506,164 | 511,136 | 579,367 |  |  |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 361,031 | 285,729 | $ 129,621 |  |  |  |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | 57,946 |  |  |  |  |  |  |  |  |
Reinsurance | Other specialty | 2021 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 590,091 | 589,452 |  |  |  |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 300,025 | $ 146,503 |  |  |  |  |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | 148,264 |  |  |  |  |  |  |  |  |
Reinsurance | Other specialty | 2022 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 924,130 |  |  |  |  |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 175,834 |  |  |  |  |  |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | $ 601,334 |  |  |  |  |  |  |  |  |

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_ClaimsDevelopmentLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount, after reinsurance, of paid claims and allocated claim adjustment expense used in claims development for short-duration insurance contracts. Excludes unallocated claim adjustment expense. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 50 -Paragraph 4B -Subparagraph (b) -URI https://asc.fasb.org/extlink&oid=116884468&loc=SL65671311-158438 + Details
Name: | us-gaap_ShortdurationInsuranceContractsCumulativePaidClaimsAndAllocatedClaimAdjustmentExpenseNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Undiscounted amount, after reinsurance, of incurred-but-not-reported (IBNR) liabilities plus expected development on reported claims, for claims and allocated claim adjustment expense for short-duration insurance contracts. Excludes unallocated claim adjustment expense. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 50 -Paragraph 4E -URI https://asc.fasb.org/extlink&oid=116884468&loc=SL65671321-158438 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 50 -Paragraph 4D -Subparagraph (a) -URI https://asc.fasb.org/extlink&oid=116884468&loc=SL65671317-158438 + Details
Name: | us-gaap_ShortdurationInsuranceContractsIncurredButNotReportedIbnrClaimsLiabilityNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Undiscounted amount, after reinsurance, of incurred claims and allocated claim adjustment expense used in claims development for short-duration insurance contracts. Excludes unallocated claim adjustment expense. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 50 -Paragraph 4B -Subparagraph (a) -URI https://asc.fasb.org/extlink&oid=116884468&loc=SL65671311-158438 + Details
Name: | us-gaap_ShortdurationInsuranceContractsIncurredClaimsAndAllocatedClaimAdjustmentExpenseNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Undiscounted amount, after reinsurance, of the liability for unpaid claims and allocated claim adjustment expense for short-duration insurance contracts. Excludes unallocated claim adjustment expense. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 50 -Paragraph 4C -URI https://asc.fasb.org/extlink&oid=116884468&loc=SL65671315-158438 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 50 -Paragraph 4B -URI https://asc.fasb.org/extlink&oid=116884468&loc=SL65671311-158438 + Details
Name: | us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Undiscounted amount, after reinsurance, of the liability for unpaid claims and allocated claim adjustment expense for short-duration insurance contracts for accident years not separately presented in claim development information. Excludes unallocated claim adjustment expense. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 50 -Paragraph 4B -URI https://asc.fasb.org/extlink&oid=116884468&loc=SL65671311-158438 + Details
Name: | us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNetNotSeparatelyPresented
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=acgl_ReinsuranceSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ProductOrServiceAxis=acgl_CasualtyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShortdurationInsuranceContractsAccidentYearAxis=us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShortdurationInsuranceContractsAccidentYearAxis=us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShortdurationInsuranceContractsAccidentYearAxis=us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShortdurationInsuranceContractsAccidentYearAxis=us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShortdurationInsuranceContractsAccidentYearAxis=us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShortdurationInsuranceContractsAccidentYearAxis=us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShortdurationInsuranceContractsAccidentYearAxis=us-gaap_ShortDurationInsuranceContractAccidentYear2019Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShortdurationInsuranceContractsAccidentYearAxis=us-gaap_ShortDurationInsuranceContractAccidentYear2020Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShortdurationInsuranceContractsAccidentYearAxis=us-gaap_ShortDurationInsuranceContractAccidentYear2021Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShortdurationInsuranceContractsAccidentYearAxis=us-gaap_ShortDurationInsuranceContractAccidentYear2022Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ProductOrServiceAxis=acgl_PropertyCatastropheMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ProductOrServiceAxis=acgl_PropertyExcludingPropertyCatastropheMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ProductOrServiceAxis=acgl_MarineAndAviationMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ProductOrServiceAxis=acgl_OtherSpecialtyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |