Investments - Carrying amounts of other invested assets (Details) - USD ($) $ in Millions |
Sep. 30, 2026 |
Dec. 31, 2025 |
||
|---|---|---|---|---|
| Investments [Line Items] | ||||
| Alternative investment | $ 8,316 | $ 8,123 | ||
| Investment real estate | 971 | 985 | ||
| All other investments | 2,368 | 1,127 | ||
| Total | [1] | 11,655 | 10,235 | |
| Accumulated depreciation on investment in real estate | 468 | 406 | ||
| Fortitude Re Funds Withheld Assets | ||||
| Investments [Line Items] | ||||
| All other investments | 156 | 156 | ||
| Hedge Funds | ||||
| Investments [Line Items] | ||||
| Total | 90 | 121 | ||
| Private equity funds | ||||
| Investments [Line Items] | ||||
| Alternative investment | 7,100 | 6,500 | ||
| Total | $ 8,200 | $ 8,000 | ||
| ||||
| X | ||||||||||
- Definition Line items represent reporting 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. No definition available.
|
| X | ||||||||||
- Definition Fair value of investment other than investment in equity security, investment in debt security and equity method investment. Includes, but is not limited to, investment in certain entities that calculate net asset value per share. Example includes, but is not limited to, investment in hedge fund, venture capital fund, private equity fund, and real estate partnership or fund. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
|
| X | ||||||||||
- Definition Amount of investments classified as other. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
|
| X | ||||||||||
- Definition Includes other investments and securities that are not at fair value as of the balance sheet date and those that are not accounted for under the equity method. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
|
| X | ||||||||||
- Definition The cumulative amount of depreciation for real estate property held for investment purposes. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
|
| X | ||||||||||
- Definition Amount of real estate investment property, net of accumulated depreciation, which may include the following: (1) land available-for-sale; (2) land available-for-development; (3) investments in building and building improvements; (4) tenant allowances; (5) developments in-process; (6) rental properties; and (7) other real estate investments. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|