Future Policy Benefits Reserves - Narratives (Details) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2025 |
Jun. 30, 2024 |
Jun. 30, 2025 |
Jun. 30, 2024 |
|
| Insurance [Abstract] | ||||
| Liability for future policy benefit, expected future gross premium, discounted, before reinsurance | $ 3,500 | $ 3,500 | $ 3,500 | $ 3,500 |
| Liability for future policy benefit, weighted-average duration (in years) | 11 years | 11 years | 11 years | 11 years |
| Liability for future policy benefit, adverse development, expense | $ 14 | $ 24 | $ 28 | $ 44 |
| Liability future policy benefit, losses recognized in prior period | $ 5 | $ 6 | $ 11 | $ 8 |