XML 91 R70.htm IDEA: XBRL DOCUMENT
v3.25.0.1

Short Duration Contracts - Claims development - Insurance (Details) $ in Millions | Dec. 31, 2024 USD ($) claims | Dec. 31, 2023 USD ($) | 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 ($) | Dec. 31, 2015 USD ($)
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |  |  |  |  |  |
Liabilities for losses and loss adjustment expenses, net of reinsurance | $ 21,118 |  |  |  |  |  |  |  |  |
Insurance | Property, energy, marine and aviation |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 3,272 |  |  |  |  |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 2,177 |  |  |  |  |  |  |  |  |
All outstanding liabilities before 2015, net of reinsurance | 19 |  |  |  |  |  |  |  |  |
Liabilities for losses and loss adjustment expenses, net of reinsurance | 1,114 |  |  |  |  |  |  |  |  |
Insurance | Property, energy, marine and aviation | 2015 |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 89 | $ 89 | $ 91 | $ 92 | $ 92 | $ 98 | $ 102 | $ 104 | $ 110 | $ 112
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 86 | 86 | 88 | 87 | 86 | 88 | 86 | 76 | 65 | 24
Total of IBNR liabilities plus expected development on reported claims | $ 1 |  |  |  |  |  |  |  |  |
Cumulative number of reported claims | claims | 4,535 |  |  |  |  |  |  |  |  |
Insurance | Property, energy, marine and aviation | 2016 |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | $ 86 | 87 | 87 | 92 | 96 | 100 | 105 | 101 | 104 |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 86 | 87 | 87 | 91 | 94 | 97 | 98 | 83 | 25 |
Total of IBNR liabilities plus expected development on reported claims | $ 0 |  |  |  |  |  |  |  |  |
Cumulative number of reported claims | claims | 6,177 |  |  |  |  |  |  |  |  |
Insurance | Property, energy, marine and aviation | 2017 |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | $ 224 | 225 | 225 | 231 | 230 | 236 | 246 | 281 |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 221 | 220 | 218 | 216 | 212 | 196 | 140 | 30 |  |
Total of IBNR liabilities plus expected development on reported claims | $ 0 |  |  |  |  |  |  |  |  |
Cumulative number of reported claims | claims | 6,481 |  |  |  |  |  |  |  |  |
Insurance | Property, energy, marine and aviation | 2018 |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | $ 170 | 172 | 170 | 170 | 174 | 186 | 181 |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 157 | 154 | 150 | 143 | 135 | 102 | 30 |  |  |
Total of IBNR liabilities plus expected development on reported claims | $ 4 |  |  |  |  |  |  |  |  |
Cumulative number of reported claims | claims | 5,085 |  |  |  |  |  |  |  |  |
Insurance | Property, energy, marine and aviation | 2019 |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | $ 156 | 159 | 161 | 165 | 179 | 179 |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 153 | 148 | 139 | 134 | 105 | 26 |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | $ (2) |  |  |  |  |  |  |  |  |
Cumulative number of reported claims | claims | 7,436 |  |  |  |  |  |  |  |  |
Insurance | Property, energy, marine and aviation | 2020 |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | $ 337 | 333 | 336 | 329 | 359 |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 306 | 293 | 251 | 194 | 56 |  |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | $ 3 |  |  |  |  |  |  |  |  |
Cumulative number of reported claims | claims | 8,682 |  |  |  |  |  |  |  |  |
Insurance | Property, energy, marine and aviation | 2021 |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | $ 421 | 423 | 429 | 427 |  |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 365 | 343 | 268 | 90 |  |  |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | $ 19 |  |  |  |  |  |  |  |  |
Cumulative number of reported claims | claims | 10,077 |  |  |  |  |  |  |  |  |
Insurance | Property, energy, marine and aviation | 2022 |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | $ 576 | 495 | 522 |  |  |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 337 | 276 | 100 |  |  |  |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | $ 148 |  |  |  |  |  |  |  |  |
Cumulative number of reported claims | claims | 15,860 |  |  |  |  |  |  |  |  |
Insurance | Property, energy, marine and aviation | 2023 |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | $ 510 | 571 |  |  |  |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 271 | 146 |  |  |  |  |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | $ 110 |  |  |  |  |  |  |  |  |
Cumulative number of reported claims | claims | 20,178 |  |  |  |  |  |  |  |  |
Insurance | Property, energy, marine and aviation | 2024 |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | $ 703 |  |  |  |  |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 195 |  |  |  |  |  |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | $ 348 |  |  |  |  |  |  |  |  |
Cumulative number of reported claims | claims | 17,889 |  |  |  |  |  |  |  |  |
Insurance | Third party occurrence business |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | $ 5,966 |  |  |  |  |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 2,339 |  |  |  |  |  |  |  |  |
All outstanding liabilities before 2015, net of reinsurance | 339 |  |  |  |  |  |  |  |  |
Liabilities for losses and loss adjustment expenses, net of reinsurance | 3,966 |  |  |  |  |  |  |  |  |
Insurance | Third party occurrence business | 2015 |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 365 | 377 | 379 | 386 | 382 | 391 | 392 | 398 | 391 | 359
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 276 | 268 | 249 | 227 | 211 | 181 | 139 | 88 | 44 | 11
Total of IBNR liabilities plus expected development on reported claims | $ 51 |  |  |  |  |  |  |  |  |
Cumulative number of reported claims | claims | 78,553 |  |  |  |  |  |  |  |  |
Insurance | Third party occurrence business | 2016 |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | $ 345 | 352 | 363 | 367 | 375 | 399 | 406 | 394 | 389 |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 246 | 230 | 215 | 195 | 164 | 137 | 88 | 42 | 12 |
Total of IBNR liabilities plus expected development on reported claims | $ 67 |  |  |  |  |  |  |  |  |
Cumulative number of reported claims | claims | 78,811 |  |  |  |  |  |  |  |  |
Insurance | Third party occurrence business | 2017 |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | $ 408 | 404 | 406 | 407 | 412 | 422 | 418 | 417 |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 271 | 247 | 221 | 165 | 135 | 100 | 52 | 13 |  |
Total of IBNR liabilities plus expected development on reported claims | $ 89 |  |  |  |  |  |  |  |  |
Cumulative number of reported claims | claims | 84,682 |  |  |  |  |  |  |  |  |
Insurance | Third party occurrence business | 2018 |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | $ 448 | 461 | 459 | 451 | 450 | 453 | 430 |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 271 | 247 | 200 | 154 | 115 | 64 | 17 |  |  |
Total of IBNR liabilities plus expected development on reported claims | $ 106 |  |  |  |  |  |  |  |  |
Cumulative number of reported claims | claims | 79,202 |  |  |  |  |  |  |  |  |
Insurance | Third party occurrence business | 2019 |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | $ 451 | 470 | 471 | 480 | 487 | 456 |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 255 | 214 | 173 | 122 | 73 | 18 |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | $ 122 |  |  |  |  |  |  |  |  |
Cumulative number of reported claims | claims | 88,964 |  |  |  |  |  |  |  |  |
Insurance | Third party occurrence business | 2020 |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | $ 606 | 632 | 640 | 616 | 606 |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 318 | 235 | 155 | 76 | 24 |  |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | $ 138 |  |  |  |  |  |  |  |  |
Cumulative number of reported claims | claims | 98,530 |  |  |  |  |  |  |  |  |
Insurance | Third party occurrence business | 2021 |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | $ 671 | 659 | 662 | 622 |  |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 323 | 174 | 91 | 26 |  |  |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | $ 147 |  |  |  |  |  |  |  |  |
Cumulative number of reported claims | claims | 99,287 |  |  |  |  |  |  |  |  |
Insurance | Third party occurrence business | 2022 |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | $ 735 | 726 | 688 |  |  |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 186 | 85 | 24 |  |  |  |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | $ 408 |  |  |  |  |  |  |  |  |
Cumulative number of reported claims | claims | 100,455 |  |  |  |  |  |  |  |  |
Insurance | Third party occurrence business | 2023 |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | $ 936 | 877 |  |  |  |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 156 | 32 |  |  |  |  |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | $ 622 |  |  |  |  |  |  |  |  |
Cumulative number of reported claims | claims | 102,558 |  |  |  |  |  |  |  |  |
Insurance | Third party occurrence business | 2024 |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | $ 1,001 |  |  |  |  |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 37 |  |  |  |  |  |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | $ 883 |  |  |  |  |  |  |  |  |
Cumulative number of reported claims | claims | 83,386 |  |  |  |  |  |  |  |  |
Insurance | Third party claims-made business |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | $ 4,745 |  |  |  |  |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 2,302 |  |  |  |  |  |  |  |  |
All outstanding liabilities before 2015, net of reinsurance | 90 |  |  |  |  |  |  |  |  |
Liabilities for losses and loss adjustment expenses, net of reinsurance | 2,533 |  |  |  |  |  |  |  |  |
Insurance | Third party claims-made business | 2015 |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 268 | 274 | 267 | 268 | 252 | 255 | 260 | 276 | 277 | 259
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 248 | 242 | 221 | 217 | 193 | 174 | 126 | 100 | 52 | 9
Total of IBNR liabilities plus expected development on reported claims | $ 6 |  |  |  |  |  |  |  |  |
Cumulative number of reported claims | claims | 13,955 |  |  |  |  |  |  |  |  |
Insurance | Third party claims-made business | 2016 |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | $ 329 | 327 | 329 | 327 | 322 | 314 | 308 | 291 | 275 |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 296 | 295 | 257 | 242 | 205 | 158 | 127 | 68 | 11 |
Total of IBNR liabilities plus expected development on reported claims | $ 16 |  |  |  |  |  |  |  |  |
Cumulative number of reported claims | claims | 14,892 |  |  |  |  |  |  |  |  |
Insurance | Third party claims-made business | 2017 |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | $ 339 | 337 | 316 | 323 | 308 | 311 | 285 | 270 |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 276 | 257 | 232 | 196 | 143 | 113 | 67 | 9 |  |
Total of IBNR liabilities plus expected development on reported claims | $ 42 |  |  |  |  |  |  |  |  |
Cumulative number of reported claims | claims | 15,484 |  |  |  |  |  |  |  |  |
Insurance | Third party claims-made business | 2018 |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | $ 366 | 366 | 347 | 336 | 319 | 314 | 272 |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 285 | 258 | 208 | 158 | 118 | 68 | 12 |  |  |
Total of IBNR liabilities plus expected development on reported claims | $ 33 |  |  |  |  |  |  |  |  |
Cumulative number of reported claims | claims | 17,094 |  |  |  |  |  |  |  |  |
Insurance | Third party claims-made business | 2019 |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | $ 329 | 329 | 322 | 317 | 317 | 289 |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 235 | 196 | 154 | 122 | 65 | 12 |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | $ 49 |  |  |  |  |  |  |  |  |
Cumulative number of reported claims | claims | 16,723 |  |  |  |  |  |  |  |  |
Insurance | Third party claims-made business | 2020 |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | $ 432 | 445 | 423 | 412 | 383 |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 265 | 214 | 151 | 87 | 17 |  |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | $ 86 |  |  |  |  |  |  |  |  |
Cumulative number of reported claims | claims | 16,816 |  |  |  |  |  |  |  |  |
Insurance | Third party claims-made business | 2021 |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | $ 461 | 499 | 517 | 514 |  |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 223 | 162 | 90 | 23 |  |  |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | $ 176 |  |  |  |  |  |  |  |  |
Cumulative number of reported claims | claims | 18,086 |  |  |  |  |  |  |  |  |
Insurance | Third party claims-made business | 2022 |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | $ 589 | 654 | 668 |  |  |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 218 | 100 | 25 |  |  |  |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | $ 257 |  |  |  |  |  |  |  |  |
Cumulative number of reported claims | claims | 19,825 |  |  |  |  |  |  |  |  |
Insurance | Third party claims-made business | 2023 |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | $ 895 | 809 |  |  |  |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 200 | 64 |  |  |  |  |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | $ 543 |  |  |  |  |  |  |  |  |
Cumulative number of reported claims | claims | 23,671 |  |  |  |  |  |  |  |  |
Insurance | Third party claims-made business | 2024 |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | $ 737 |  |  |  |  |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 56 |  |  |  |  |  |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | $ 577 |  |  |  |  |  |  |  |  |
Cumulative number of reported claims | claims | 23,155 |  |  |  |  |  |  |  |  |
Insurance | Multi-line and other specialty |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | $ 6,518 |  |  |  |  |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 4,606 |  |  |  |  |  |  |  |  |
All outstanding liabilities before 2015, net of reinsurance | 29 |  |  |  |  |  |  |  |  |
Liabilities for losses and loss adjustment expenses, net of reinsurance | 1,941 |  |  |  |  |  |  |  |  |
Insurance | Multi-line and other specialty | 2015 |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 344 | 344 | 345 | 347 | 349 | 356 | 365 | 356 | 358 | 334
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 337 | 333 | 331 | 330 | 326 | 321 | 306 | 278 | 236 | $ 138
Total of IBNR liabilities plus expected development on reported claims | $ 3 |  |  |  |  |  |  |  |  |
Cumulative number of reported claims | claims | 181,424 |  |  |  |  |  |  |  |  |
Insurance | Multi-line and other specialty | 2016 |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | $ 404 | 406 | 408 | 408 | 410 | 416 | 427 | 431 | 408 |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 396 | 391 | 390 | 385 | 379 | 363 | 341 | 304 | $ 176 |
Total of IBNR liabilities plus expected development on reported claims | $ 4 |  |  |  |  |  |  |  |  |
Cumulative number of reported claims | claims | 195,233 |  |  |  |  |  |  |  |  |
Insurance | Multi-line and other specialty | 2017 |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | $ 514 | 516 | 512 | 504 | 500 | 491 | 500 | 482 |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 493 | 479 | 472 | 446 | 423 | 380 | 342 | $ 181 |  |
Total of IBNR liabilities plus expected development on reported claims | $ 6 |  |  |  |  |  |  |  |  |
Cumulative number of reported claims | claims | 236,433 |  |  |  |  |  |  |  |  |
Insurance | Multi-line and other specialty | 2018 |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | $ 564 | 564 | 564 | 564 | 562 | 564 | 512 |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 543 | 526 | 508 | 479 | 442 | 389 | $ 211 |  |  |
Total of IBNR liabilities plus expected development on reported claims | $ 9 |  |  |  |  |  |  |  |  |
Cumulative number of reported claims | claims | 266,125 |  |  |  |  |  |  |  |  |
Insurance | Multi-line and other specialty | 2019 |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | $ 671 | 656 | 650 | 639 | 611 | 566 |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 611 | 576 | 548 | 486 | 385 | $ 212 |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | $ 11 |  |  |  |  |  |  |  |  |
Cumulative number of reported claims | claims | 249,876 |  |  |  |  |  |  |  |  |
Insurance | Multi-line and other specialty | 2020 |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | $ 519 | 515 | 513 | 567 | 616 |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 450 | 405 | 358 | 308 | $ 171 |  |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | $ 26 |  |  |  |  |  |  |  |  |
Cumulative number of reported claims | claims | 168,232 |  |  |  |  |  |  |  |  |
Insurance | Multi-line and other specialty | 2021 |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | $ 635 | 614 | 618 | 634 |  |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 511 | 427 | 334 | $ 157 |  |  |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | $ 42 |  |  |  |  |  |  |  |  |
Cumulative number of reported claims | claims | 112,591 |  |  |  |  |  |  |  |  |
Insurance | Multi-line and other specialty | 2022 |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | $ 639 | 640 | 677 |  |  |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 439 | 370 | $ 177 |  |  |  |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | $ 90 |  |  |  |  |  |  |  |  |
Cumulative number of reported claims | claims | 144,429 |  |  |  |  |  |  |  |  |
Insurance | Multi-line and other specialty | 2023 |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | $ 809 | 815 |  |  |  |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 489 | $ 253 |  |  |  |  |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | $ 199 |  |  |  |  |  |  |  |  |
Cumulative number of reported claims | claims | 161,842 |  |  |  |  |  |  |  |  |
Insurance | Multi-line and other specialty | 2024 |  |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items] |  |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | $ 1,419 |  |  |  |  |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 337 |  |  |  |  |  |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | $ 885 |  |  |  |  |  |  |  |  |
Cumulative number of reported claims | claims | 145,190 |  |  |  |  |  |  |  |  |

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://www.xbrl.org/2003/role/exampleRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 55 -Paragraph 9E -Publisher FASB -URI https://asc.fasb.org/1943274/2147480046/944-40-55-9E Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 4B -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-4B + 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://www.xbrl.org/2003/role/exampleRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 55 -Paragraph 9E -Publisher FASB -URI https://asc.fasb.org/1943274/2147480046/944-40-55-9E Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 4E -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-4E Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 4D -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-4D + 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://www.xbrl.org/2003/role/exampleRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 55 -Paragraph 9E -Publisher FASB -URI https://asc.fasb.org/1943274/2147480046/944-40-55-9E Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 4B -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-4B + 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://www.xbrl.org/2003/role/exampleRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 55 -Paragraph 9E -Publisher FASB -URI https://asc.fasb.org/1943274/2147480046/944-40-55-9E Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 4C -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-4C Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 4B -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-4B + 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://www.xbrl.org/2003/role/exampleRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 55 -Paragraph 9E -Publisher FASB -URI https://asc.fasb.org/1943274/2147480046/944-40-55-9E Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 4B -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-4B + Details
Name: | us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNetNotSeparatelyPresented
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Cumulative number of reported claims for short-duration insurance contracts. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 55 -Paragraph 9E -Publisher FASB -URI https://asc.fasb.org/1943274/2147480046/944-40-55-9E Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 4D -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-4D + Details
Name: | us-gaap_ShortdurationInsuranceContractsNumberOfReportedClaims
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

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 Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 55 -Paragraph 9E -Publisher FASB -URI https://asc.fasb.org/1943274/2147480046/944-40-55-9E Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 4C -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-4C + Details
Name: | us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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

X
- Details
Name: | srt_ProductOrServiceAxis=acgl_PropertyEnergyMarineAndAviationMember
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: | us-gaap_ShortdurationInsuranceContractsAccidentYearAxis=us-gaap_ShortDurationInsuranceContractAccidentYear2023Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShortdurationInsuranceContractsAccidentYearAxis=us-gaap_ShortDurationInsuranceContractAccidentYear2024Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

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

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