Insurance Liabilities - Discounting of Reserves (Details) - USD ($) $ in Millions |
6 Months Ended | 12 Months Ended |
|---|---|---|
Jun. 30, 2026 |
Dec. 31, 2025 |
|
| Discounting of Reserves [Line Items] | ||
| U.S. workers' compensation | $ 2,083 | $ 2,063 |
| Retroactive reinsurance | (819) | (891) |
| Total reserve discount | 1,264 | 1,172 |
| Fortitude RE | ||
| Discounting of Reserves [Line Items] | ||
| Total reserve discount | $ 681 | $ 693 |
| Discount ceded on sale (as a percent) | 100.00% | 100.00% |
| United Kingdom | ||
| Discounting of Reserves [Line Items] | ||
| Total reserve discount | $ 163 | $ 166 |