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Insurance - Short-duration insurance contracts, claims development (Details) - Property and casualty insurance $ in Millions | Dec. 31, 2023 USD ($) claim | Dec. 31, 2022 USD ($) | 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] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | $ 25,304 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | 18,181 |  |  |  |  |  |  |  |  |
Unpaid losses and LAE — 11th year and prior (excluding unallocated LAE) | 405 |  |  |  |  |  |  |  |  |
Unpaid losses and LAE, net of reinsurance (excluding unallocated LAE) | 7,528 |  |  |  |  |  |  |  |  |
Accident Year 2014 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | 1,957 | $ 1,958 | $ 1,954 | $ 1,957 | $ 1,978 | $ 2,004 | $ 2,038 | $ 2,040 | $ 2,050 | $ 2,083
Total IBNR Plus Expected Development on Reported Claims | $ 36 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | claim | 220,128 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | $ 1,893 | 1,870 | 1,847 | 1,812 | 1,773 | 1,705 | 1,588 | 1,422 | 1,174 | 594
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance | 96.70% |  |  |  |  |  |  |  |  |
Accident Year 2015 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | $ 1,991 | 1,998 | 2,003 | 2,013 | 2,022 | 2,038 | 2,041 | 2,047 | 2,114 |
Total IBNR Plus Expected Development on Reported Claims | $ 45 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | claim | 231,168 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | $ 1,909 | 1,878 | 1,847 | 1,791 | 1,722 | 1,592 | 1,404 | 1,129 | 619 |
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance | 95.90% |  |  |  |  |  |  |  |  |
Accident Year 2016 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | $ 1,974 | 1,986 | 2,004 | 2,034 | 2,060 | 2,082 | 2,083 | 2,117 |  |
Total IBNR Plus Expected Development on Reported Claims | $ 80 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | claim | 223,280 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | $ 1,848 | 1,806 | 1,750 | 1,662 | 1,539 | 1,350 | 1,099 | 577 |  |
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance | 93.60% |  |  |  |  |  |  |  |  |
Accident Year 2017 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | $ 2,266 | 2,256 | 2,269 | 2,301 | 2,329 | 2,348 | 2,375 |  |  |
Total IBNR Plus Expected Development on Reported Claims | $ 134 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | claim | 247,224 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | $ 2,030 | 1,953 | 1,844 | 1,736 | 1,524 | 1,250 | 709 |  |  |
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance | 89.60% |  |  |  |  |  |  |  |  |
Accident Year 2018 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | $ 2,449 | 2,452 | 2,439 | 2,499 | 2,516 | 2,507 |  |  |  |
Total IBNR Plus Expected Development on Reported Claims | $ 211 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | claim | 236,982 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | $ 2,099 | 1,977 | 1,807 | 1,606 | 1,337 | 730 |  |  |  |
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance | 85.70% |  |  |  |  |  |  |  |  |
Accident Year 2019 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | $ 2,642 | 2,632 | 2,672 | 2,674 | 2,721 |  |  |  |  |
Total IBNR Plus Expected Development on Reported Claims | $ 286 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | claim | 255,871 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | $ 2,160 | 1,983 | 1,768 | 1,448 | 847 |  |  |  |  |
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance | 81.80% |  |  |  |  |  |  |  |  |
Accident year 2020 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | $ 2,500 | 2,546 | 2,635 | 2,748 |  |  |  |  |  |
Total IBNR Plus Expected Development on Reported Claims | $ 406 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | claim | 205,973 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | $ 1,842 | 1,620 | 1,337 | 758 |  |  |  |  |  |
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance | 73.70% |  |  |  |  |  |  |  |  |
Accident Year 2021 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | $ 2,689 | 2,754 | 2,861 |  |  |  |  |  |  |
Total IBNR Plus Expected Development on Reported Claims | $ 660 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | claim | 206,733 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | $ 1,687 | 1,368 | 746 |  |  |  |  |  |  |
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance | 62.70% |  |  |  |  |  |  |  |  |
Accident Year 2022 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | $ 3,205 | 3,270 |  |  |  |  |  |  |  |
Total IBNR Plus Expected Development on Reported Claims | $ 1,000 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | claim | 216,920 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | $ 1,724 | 904 |  |  |  |  |  |  |  |
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance | 53.80% |  |  |  |  |  |  |  |  |
Accident Year 2023 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | $ 3,631 |  |  |  |  |  |  |  |  |
Total IBNR Plus Expected Development on Reported Claims | $ 1,731 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | claim | 201,558 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | $ 989 |  |  |  |  |  |  |  |  |
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance | 27.20% |  |  |  |  |  |  |  |  |
Excludes short-duration insurance contracts detail for accident years not separately presented |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Unpaid losses and LAE, net of reinsurance (excluding unallocated LAE) | $ 7,123 |  |  |  |  |  |  |  |  |
Property and transportation |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | 9,770 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | 8,160 |  |  |  |  |  |  |  |  |
Unpaid losses and LAE — 11th year and prior (excluding unallocated LAE) | 26 |  |  |  |  |  |  |  |  |
Unpaid losses and LAE, net of reinsurance (excluding unallocated LAE) | 1,636 |  |  |  |  |  |  |  |  |
Property and transportation | Accident Year 2014 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | 800 | 800 | 802 | 804 | 808 | 815 | 820 | 817 | 828 | 844
Total IBNR Plus Expected Development on Reported Claims | $ 5 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | claim | 133,284 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | $ 793 | 792 | 791 | 789 | 783 | 770 | 744 | 693 | 632 | 329
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance | 99.10% |  |  |  |  |  |  |  |  |
Property and transportation | Accident Year 2015 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | $ 769 | 769 | 768 | 772 | 777 | 777 | 779 | 784 | 818 |
Total IBNR Plus Expected Development on Reported Claims | $ 4 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | claim | 135,083 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | $ 761 | 755 | 750 | 744 | 736 | 707 | 667 | 582 | 359 |
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance | 99.00% |  |  |  |  |  |  |  |  |
Property and transportation | Accident Year 2016 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | $ 689 | 689 | 688 | 694 | 706 | 714 | 716 | 746 |  |
Total IBNR Plus Expected Development on Reported Claims | $ 8 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | claim | 121,400 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | $ 672 | 665 | 656 | 640 | 618 | 577 | 521 | 294 |  |
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance | 97.50% |  |  |  |  |  |  |  |  |
Property and transportation | Accident Year 2017 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | $ 820 | 820 | 816 | 823 | 843 | 847 | 889 |  |  |
Total IBNR Plus Expected Development on Reported Claims | $ 11 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | claim | 140,998 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | $ 794 | 783 | 755 | 735 | 696 | 640 | 379 |  |  |
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance | 96.80% |  |  |  |  |  |  |  |  |
Property and transportation | Accident Year 2018 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | $ 876 | 882 | 876 | 886 | 902 | 932 |  |  |  |
Total IBNR Plus Expected Development on Reported Claims | $ 15 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | claim | 130,721 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | $ 838 | 824 | 781 | 738 | 676 | 396 |  |  |  |
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance | 95.70% |  |  |  |  |  |  |  |  |
Property and transportation | Accident Year 2019 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | $ 1,057 | 1,055 | 1,051 | 1,058 | 1,111 |  |  |  |  |
Total IBNR Plus Expected Development on Reported Claims | $ 26 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | claim | 154,248 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | $ 998 | 959 | 904 | 823 | 527 |  |  |  |  |
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance | 94.40% |  |  |  |  |  |  |  |  |
Property and transportation | Accident year 2020 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | $ 949 | 957 | 974 | 1,043 |  |  |  |  |  |
Total IBNR Plus Expected Development on Reported Claims | $ 39 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | claim | 122,112 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | $ 857 | 804 | 726 | 461 |  |  |  |  |  |
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance | 90.30% |  |  |  |  |  |  |  |  |
Property and transportation | Accident Year 2021 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | $ 1,022 | 1,023 | 1,119 |  |  |  |  |  |  |
Total IBNR Plus Expected Development on Reported Claims | $ 69 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | claim | 123,416 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | $ 867 | 767 | 449 |  |  |  |  |  |  |
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance | 84.80% |  |  |  |  |  |  |  |  |
Property and transportation | Accident Year 2022 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | $ 1,316 | 1,393 |  |  |  |  |  |  |  |
Total IBNR Plus Expected Development on Reported Claims | $ 157 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | claim | 136,540 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | $ 1,018 | 587 |  |  |  |  |  |  |  |
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance | 77.40% |  |  |  |  |  |  |  |  |
Property and transportation | Accident Year 2023 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | $ 1,472 |  |  |  |  |  |  |  |  |
Total IBNR Plus Expected Development on Reported Claims | $ 432 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | claim | 127,664 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | $ 562 |  |  |  |  |  |  |  |  |
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance | 38.20% |  |  |  |  |  |  |  |  |
Property and transportation | Excludes short-duration insurance contracts detail for accident years not separately presented |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Unpaid losses and LAE, net of reinsurance (excluding unallocated LAE) | $ 1,610 |  |  |  |  |  |  |  |  |
Specialty casualty |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | 12,401 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | 7,771 |  |  |  |  |  |  |  |  |
Unpaid losses and LAE — 11th year and prior (excluding unallocated LAE) | 354 |  |  |  |  |  |  |  |  |
Unpaid losses and LAE, net of reinsurance (excluding unallocated LAE) | 4,984 |  |  |  |  |  |  |  |  |
Specialty casualty | Accident Year 2014 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | 951 | 955 | 950 | 952 | 967 | 982 | 1,006 | 1,008 | 1,008 | 1,035
Total IBNR Plus Expected Development on Reported Claims | $ 28 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | claim | 57,373 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | $ 899 | 881 | 862 | 829 | 801 | 755 | 680 | 574 | 412 | 190
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance | 94.50% |  |  |  |  |  |  |  |  |
Specialty casualty | Accident Year 2015 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | $ 1,002 | 1,007 | 1,015 | 1,021 | 1,024 | 1,042 | 1,041 | 1,043 | 1,081 |
Total IBNR Plus Expected Development on Reported Claims | $ 36 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | claim | 58,456 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | $ 934 | 913 | 888 | 844 | 792 | 702 | 577 | 411 | 178 |
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance | 93.20% |  |  |  |  |  |  |  |  |
Specialty casualty | Accident Year 2016 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | $ 1,036 | 1,046 | 1,069 | 1,090 | 1,101 | 1,116 | 1,122 | 1,131 |  |
Total IBNR Plus Expected Development on Reported Claims | $ 63 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | claim | 56,695 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | $ 938 | 906 | 870 | 806 | 713 | 584 | 418 | 186 |  |
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance | 90.50% |  |  |  |  |  |  |  |  |
Specialty casualty | Accident Year 2017 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | $ 1,139 | 1,139 | 1,162 | 1,189 | 1,204 | 1,221 | 1,211 |  |  |
Total IBNR Plus Expected Development on Reported Claims | $ 110 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | claim | 57,386 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | $ 959 | 902 | 833 | 755 | 612 | 422 | 200 |  |  |
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance | 84.20% |  |  |  |  |  |  |  |  |
Specialty casualty | Accident Year 2018 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | $ 1,264 | 1,269 | 1,262 | 1,302 | 1,307 | 1,277 |  |  |  |
Total IBNR Plus Expected Development on Reported Claims | $ 169 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | claim | 59,456 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | $ 991 | 901 | 794 | 649 | 475 | 210 |  |  |  |
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance | 78.40% |  |  |  |  |  |  |  |  |
Specialty casualty | Accident Year 2019 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | $ 1,284 | 1,280 | 1,322 | 1,311 | 1,308 |  |  |  |  |
Total IBNR Plus Expected Development on Reported Claims | $ 230 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | claim | 59,684 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | $ 913 | 795 | 651 | 455 | 212 |  |  |  |  |
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance | 71.10% |  |  |  |  |  |  |  |  |
Specialty casualty | Accident year 2020 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | $ 1,232 | 1,258 | 1,329 | 1,352 |  |  |  |  |  |
Total IBNR Plus Expected Development on Reported Claims | $ 313 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | claim | 54,129 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | $ 757 | 613 | 446 | 188 |  |  |  |  |  |
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance | 61.40% |  |  |  |  |  |  |  |  |
Specialty casualty | Accident Year 2021 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | $ 1,342 | 1,389 | 1,384 |  |  |  |  |  |  |
Total IBNR Plus Expected Development on Reported Claims | $ 497 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | claim | 55,962 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | $ 625 | 438 | 191 |  |  |  |  |  |  |
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance | 46.60% |  |  |  |  |  |  |  |  |
Specialty casualty | Accident Year 2022 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | $ 1,503 | 1,475 |  |  |  |  |  |  |  |
Total IBNR Plus Expected Development on Reported Claims | $ 697 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | claim | 56,742 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | $ 507 | 198 |  |  |  |  |  |  |  |
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance | 33.70% |  |  |  |  |  |  |  |  |
Specialty casualty | Accident Year 2023 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | $ 1,648 |  |  |  |  |  |  |  |  |
Total IBNR Plus Expected Development on Reported Claims | $ 1,035 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | claim | 53,352 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | $ 248 |  |  |  |  |  |  |  |  |
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance | 15.00% |  |  |  |  |  |  |  |  |
Specialty casualty | Excludes short-duration insurance contracts detail for accident years not separately presented |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Unpaid losses and LAE, net of reinsurance (excluding unallocated LAE) | $ 4,630 |  |  |  |  |  |  |  |  |
Specialty financial |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | 1,953 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | 1,625 |  |  |  |  |  |  |  |  |
Unpaid losses and LAE — 11th year and prior (excluding unallocated LAE) | 0 |  |  |  |  |  |  |  |  |
Unpaid losses and LAE, net of reinsurance (excluding unallocated LAE) | 328 |  |  |  |  |  |  |  |  |
Specialty financial | Accident Year 2014 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | 134 | 135 | 136 | 137 | 142 | 147 | 153 | 156 | 157 | 146
Total IBNR Plus Expected Development on Reported Claims | $ 0 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | claim | 29,471 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | $ 141 | 141 | 140 | 141 | 139 | 137 | 128 | 125 | 109 | 62
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance | 105.20% |  |  |  |  |  |  |  |  |
Specialty financial | Accident Year 2015 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | $ 133 | 135 | 136 | 138 | 145 | 153 | 158 | 160 | 156 |
Total IBNR Plus Expected Development on Reported Claims | $ 0 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | claim | 37,629 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | $ 133 | 134 | 134 | 134 | 132 | 133 | 129 | 110 | 72 |
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance | 100.00% |  |  |  |  |  |  |  |  |
Specialty financial | Accident Year 2016 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | $ 172 | 173 | 170 | 174 | 182 | 187 | 184 | 179 |  |
Total IBNR Plus Expected Development on Reported Claims | $ 1 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | claim | 45,185 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | $ 172 | 171 | 164 | 163 | 161 | 158 | 141 | 88 |  |
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance | 100.00% |  |  |  |  |  |  |  |  |
Specialty financial | Accident Year 2017 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | $ 210 | 202 | 203 | 208 | 212 | 215 | 212 |  |  |
Total IBNR Plus Expected Development on Reported Claims | $ 5 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | claim | 48,840 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | $ 194 | 192 | 193 | 194 | 186 | 169 | 120 |  |  |
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance | 92.40% |  |  |  |  |  |  |  |  |
Specialty financial | Accident Year 2018 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | $ 198 | 201 | 207 | 219 | 217 | 212 |  |  |  |
Total IBNR Plus Expected Development on Reported Claims | $ 6 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | claim | 46,805 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | $ 193 | 192 | 188 | 187 | 163 | 112 |  |  |  |
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance | 97.50% |  |  |  |  |  |  |  |  |
Specialty financial | Accident Year 2019 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | $ 182 | 186 | 191 | 198 | 194 |  |  |  |  |
Total IBNR Plus Expected Development on Reported Claims | $ 9 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | claim | 41,939 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | $ 170 | 168 | 164 | 146 | 99 |  |  |  |  |
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance | 93.40% |  |  |  |  |  |  |  |  |
Specialty financial | Accident year 2020 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | $ 193 | 202 | 215 | 231 |  |  |  |  |  |
Total IBNR Plus Expected Development on Reported Claims | $ 15 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | claim | 29,732 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | $ 162 | 159 | 144 | 100 |  |  |  |  |  |
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance | 83.90% |  |  |  |  |  |  |  |  |
Specialty financial | Accident Year 2021 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | $ 187 | 201 | 223 |  |  |  |  |  |  |
Total IBNR Plus Expected Development on Reported Claims | $ 25 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | claim | 27,355 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | $ 146 | 136 | 98 |  |  |  |  |  |  |
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance | 78.10% |  |  |  |  |  |  |  |  |
Specialty financial | Accident Year 2022 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | $ 234 | 243 |  |  |  |  |  |  |  |
Total IBNR Plus Expected Development on Reported Claims | $ 54 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | claim | 23,638 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | $ 164 | 108 |  |  |  |  |  |  |  |
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance | 70.10% |  |  |  |  |  |  |  |  |
Specialty financial | Accident Year 2023 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | $ 310 |  |  |  |  |  |  |  |  |
Total IBNR Plus Expected Development on Reported Claims | $ 127 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | claim | 20,542 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | $ 150 |  |  |  |  |  |  |  |  |
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance | 48.40% |  |  |  |  |  |  |  |  |
Specialty financial | Excludes short-duration insurance contracts detail for accident years not separately presented |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Unpaid losses and LAE, net of reinsurance (excluding unallocated LAE) | $ 328 |  |  |  |  |  |  |  |  |
Other specialty |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | 1,180 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | 625 |  |  |  |  |  |  |  |  |
Unpaid losses and LAE — 11th year and prior (excluding unallocated LAE) | 25 |  |  |  |  |  |  |  |  |
Unpaid losses and LAE, net of reinsurance (excluding unallocated LAE) | 580 |  |  |  |  |  |  |  |  |
Other specialty | Accident Year 2014 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | 72 | 68 | 66 | 64 | 61 | 60 | 59 | 59 | 57 | 58
Total IBNR Plus Expected Development on Reported Claims | $ 3 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | claim | 0 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | $ 60 | 56 | 54 | 53 | 50 | 43 | 36 | 30 | 21 | $ 13
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance | 83.30% |  |  |  |  |  |  |  |  |
Other specialty | Accident Year 2015 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | $ 87 | 87 | 84 | 82 | 76 | 66 | 63 | 60 | 59 |
Total IBNR Plus Expected Development on Reported Claims | $ 5 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | claim | 0 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | $ 81 | 76 | 75 | 69 | 62 | 50 | 31 | 26 | $ 10 |
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance | 93.10% |  |  |  |  |  |  |  |  |
Other specialty | Accident Year 2016 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | $ 77 | 78 | 77 | 76 | 71 | 65 | 61 | 61 |  |
Total IBNR Plus Expected Development on Reported Claims | $ 8 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | claim | 0 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | $ 66 | 64 | 60 | 53 | 47 | 31 | 19 | $ 9 |  |
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance | 85.70% |  |  |  |  |  |  |  |  |
Other specialty | Accident Year 2017 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | $ 97 | 95 | 88 | 81 | 70 | 65 | 63 |  |  |
Total IBNR Plus Expected Development on Reported Claims | $ 8 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | claim | 0 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | $ 83 | 76 | 63 | 52 | 30 | 19 | $ 10 |  |  |
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance | 85.60% |  |  |  |  |  |  |  |  |
Other specialty | Accident Year 2018 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | $ 111 | 100 | 94 | 92 | 90 | 86 |  |  |  |
Total IBNR Plus Expected Development on Reported Claims | $ 21 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | claim | 0 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | $ 77 | 60 | 44 | 32 | 23 | $ 12 |  |  |  |
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance | 69.40% |  |  |  |  |  |  |  |  |
Other specialty | Accident Year 2019 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | $ 119 | 111 | 108 | 107 | 108 |  |  |  |  |
Total IBNR Plus Expected Development on Reported Claims | $ 21 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | claim | 0 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | $ 79 | 61 | 49 | 24 | $ 9 |  |  |  |  |
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance | 66.40% |  |  |  |  |  |  |  |  |
Other specialty | Accident year 2020 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | $ 126 | 129 | 117 | 122 |  |  |  |  |  |
Total IBNR Plus Expected Development on Reported Claims | $ 39 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | claim | 0 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | $ 66 | 44 | 21 | $ 9 |  |  |  |  |  |
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance | 52.40% |  |  |  |  |  |  |  |  |
Other specialty | Accident Year 2021 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | $ 138 | 141 | 135 |  |  |  |  |  |  |
Total IBNR Plus Expected Development on Reported Claims | $ 69 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | claim | 0 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | $ 49 | 27 | $ 8 |  |  |  |  |  |  |
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance | 35.50% |  |  |  |  |  |  |  |  |
Other specialty | Accident Year 2022 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | $ 152 | 159 |  |  |  |  |  |  |  |
Total IBNR Plus Expected Development on Reported Claims | $ 92 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | claim | 0 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | $ 35 | $ 11 |  |  |  |  |  |  |  |
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance | 23.00% |  |  |  |  |  |  |  |  |
Other specialty | Accident Year 2023 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred Claims and Allocated LAE, Net of Reinsurance | $ 201 |  |  |  |  |  |  |  |  |
Total IBNR Plus Expected Development on Reported Claims | $ 137 |  |  |  |  |  |  |  |  |
Cumulative Number of Reported Claims | claim | 0 |  |  |  |  |  |  |  |  |
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance | $ 29 |  |  |  |  |  |  |  |  |
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance | 14.40% |  |  |  |  |  |  |  |  |
Other specialty | Excludes short-duration insurance contracts detail for accident years not separately presented |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Unpaid losses and LAE, net of reinsurance (excluding unallocated LAE) | $ 555 |  |  |  |  |  |  |  |  |

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