Reserves for Future Policy Benefits and Claims Payable - Schedule of Rollforward of Additional Liabilities, Closed Block Life (Details) - Closed Block Life - USD ($) $ in Millions |
9 Months Ended | 12 Months Ended |
|---|---|---|
Sep. 30, 2026 |
Dec. 31, 2025 |
|
| Additional Liability, Long-Duration Insurance [Roll Forward] | ||
| Balance, beginning of period | $ 1,209 | $ 1,207 |
| Effect of changes in cash flow assumptions | 0 | 5 |
| Effect of actual variances from expected experience | 22 | 33 |
| Interest accrual | 43 | 58 |
| Net assessments collected | (80) | (94) |
| Balance, end of period | 1,194 | 1,209 |
| As Previously Reported | ||
| Additional Liability, Long-Duration Insurance [Roll Forward] | ||
| Balance, beginning of period | 1,195 | 1,184 |
| Balance, end of period | 1,137 | 1,195 |
| Cumulative effect of changes in shadow adjustments | ||
| Additional Liability, Long-Duration Insurance [Roll Forward] | ||
| Balance, beginning of period | (14) | (23) |
| Balance, end of period | $ (57) | $ (14) |