Reinsurance - Consolidated Property Casualty Insurance Assumed and Ceded Business (Details) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2026 |
Jun. 30, 2025 |
Jun. 30, 2026 |
Jun. 30, 2025 |
|
| Property Casualty Insurance Assumed And Ceded Business | ||||
| Earned premiums | $ 2,635 | $ 2,480 | $ 5,239 | $ 4,824 |
| Incurred loss and loss expenses | 1,887 | 1,660 | 3,638 | 3,628 |
| Consolidated Property And Casualty Insurance | ||||
| Property Casualty Insurance Assumed And Ceded Business | ||||
| Direct written premiums | 2,739 | 2,672 | 5,246 | 5,060 |
| Assumed written premiums | 216 | 196 | 497 | 499 |
| Ceded written premiums | (130) | (135) | (250) | (331) |
| Net written premiums | 2,825 | 2,733 | 5,493 | 5,228 |
| Direct earned premiums | 2,479 | 2,333 | 4,927 | 4,580 |
| Assumed earned premiums | 170 | 162 | 337 | 352 |
| Ceded earned premiums | (101) | (98) | (197) | (271) |
| Earned premiums | 2,548 | 2,397 | 5,067 | 4,661 |
| Direct incurred loss and loss expenses | 1,759 | 1,508 | 3,354 | 3,657 |
| Assumed incurred loss and loss expenses | 84 | 91 | 165 | 327 |
| Ceded incurred loss and loss expenses | (35) | (12) | (44) | (510) |
| Incurred loss and loss expenses | $ 1,808 | $ 1,587 | $ 3,475 | $ 3,474 |
| X | ||||||||||
- Definition [Line Items] for Property Casualty Insurance Premiums Written On Assumed And Ceded Business No definition available.
|
| X | ||||||||||
- Definition Amount of earned premiums assumed from other entities. Reference 1: http://www.xbrl.org/2003/role/exampleRef
|
| X | ||||||||||
- Definition Amount of written premiums assumed from other entities. Reference 1: http://www.xbrl.org/2003/role/exampleRef
|
| X | ||||||||||
- Definition Amount of earned premiums ceded to other entities. Reference 1: http://www.xbrl.org/2003/role/exampleRef
|
| X | ||||||||||
- Definition Amount of written premiums ceded to other entities. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
|
| X | ||||||||||
- Definition Amount, before premiums ceded to other entities and premiums assumed by the entity, of premiums earned. Reference 1: http://www.xbrl.org/2003/role/exampleRef
|
| X | ||||||||||
- Definition Amount, before premiums ceded to other entities and premiums assumed by the entity, of premiums written. Reference 1: http://www.xbrl.org/2003/role/exampleRef
|
| X | ||||||||||
- Definition The increase (decrease) in property and casualty insurance liabilities balances during the period. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- Definition Amount, before effect of policies assumed or ceded, of expense related to provision for policy benefits and costs incurred. Reference 1: http://www.xbrl.org/2003/role/exampleRef
|
| X | ||||||||||
- Definition Amount, after effects of policies assumed or ceded, of expense related to the provision for policy benefits and costs incurred. Reference 1: http://www.xbrl.org/2003/role/exampleRef
|
| X | ||||||||||
- Definition Amount, after premiums ceded to other entities and premiums assumed by the entity, of premiums earned. Reference 1: http://www.xbrl.org/2003/role/exampleRef
|
| X | ||||||||||
- Definition Amount of policy benefits and costs incurred for policies assumed. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
|
| X | ||||||||||
- Definition Amount of reduction of provision for policy benefits and costs incurred for policies ceded. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
|
| X | ||||||||||
- Details
|