Investments - Hybrid Securities (Detail) - USD ($) $ in Millions |
Mar. 31, 2026 |
Dec. 31, 2025 |
Mar. 31, 2025 |
|---|---|---|---|
| Hybrid Instruments [Line Items] | |||
| Hybrid securities | $ 1,700 | $ 1,525 | $ 1,211 |
| Corporate and other debt | |||
| Hybrid Instruments [Line Items] | |||
| Hybrid securities | 702 | 733 | 632 |
| Residential mortgage-backed | |||
| Hybrid Instruments [Line Items] | |||
| Hybrid securities | $ 998 | $ 792 | $ 579 |