COLLATERALIZED REINSURANCE, TRUST AGREEMENTS AND OTHER RESTRICTED ASSETS - Schedule of Premiums and Losses Ceded (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2024 |
Dec. 31, 2023 |
|
| Effects of Reinsurance [Line Items] | |||
| Ceded written premiums | $ 2,193 | $ 2,418 | $ 1,907 |
| Assumed written premiums | 13,065 | 13,117 | 11,606 |
| Mt Logan Re | |||
| Effects of Reinsurance [Line Items] | |||
| Ceded written premiums | 357 | 433 | 246 |
| Ceded earned premiums | 425 | 376 | 242 |
| Ceded losses and LAE | 168 | 188 | 64 |
| Assumed written premiums | 14 | 10 | 6 |
| Assumed earned premiums | 14 | 10 | 6 |
| Assumed losses and LAE | $ 0 | $ 0 | $ 0 |