Future Policy Benefit Reserves - Narrative (Details) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | |||
|---|---|---|---|---|---|
Jun. 30, 2025 |
Jun. 30, 2024 |
Jun. 30, 2025 |
Jun. 30, 2024 |
Dec. 31, 2024 |
|
| Insurance [Abstract] | |||||
| Liability for future policy benefit, expected future gross premium, discounted, before reinsurance | $ 3,491 | $ 3,491 | $ 3,546 | ||
| Liability for future policy benefit, weighted-average duration | 11 years | 11 years | 11 years | 11 years | |
| Liability future policy benefit, losses recognized in current period | $ 14 | $ 24 | $ 28 | $ 44 | |
| Liability future policy benefit, losses recognized in prior period | $ 5 | $ 6 | $ 11 | $ 8 | |