FAIR VALUE MEASUREMENTS - CHANGES IN VALUE OF EMBEDDED DERIVATIVES (Details) - Fair Value, Inputs, Level 3 - Fixed Index Annuity Products - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2026 |
Jun. 30, 2025 |
Jun. 30, 2026 |
Jun. 30, 2025 |
|
| Liabilities: | ||||
| Balance at beginning of the period | $ 1,564.2 | $ 1,450.2 | $ 1,600.6 | $ 1,471.6 |
| Premiums less benefits | (3.6) | (7.5) | (13.0) | (16.0) |
| Change in fair value, net | 116.1 | 59.7 | 89.1 | 46.8 |
| Balance at end of the period | $ 1,676.7 | $ 1,502.4 | $ 1,676.7 | $ 1,502.4 |