Future Policy Benefits - Schedule of Additional Information, Cohort NPR (Details) - USD ($) $ in Millions |
9 Months Ended | 12 Months Ended |
|---|---|---|
Sep. 30, 2026 |
Dec. 31, 2025 |
|
| Insurance [Abstract] | ||
| NPR before capping | 102.00% | 104.00% |
| Reserves before NPR capping | $ 1,027 | $ 1,145 |
| Reserves after NPR capping | 1,032 | 1,156 |
| Loss Expense | $ 5 | $ 11 |