Investments - Hybrid Securities (Detail) - USD ($) $ in Millions |
Jun. 30, 2025 |
Dec. 31, 2024 |
Jun. 30, 2024 |
|---|---|---|---|
| Hybrid Instruments [Line Items] | |||
| Hybrid securities | $ 1,346 | $ 1,088 | $ 888 |
| Corporate and other debt securities | |||
| Hybrid Instruments [Line Items] | |||
| Hybrid securities | 731 | 608 | 610 |
| Residential mortgage-backed securities | |||
| Hybrid Instruments [Line Items] | |||
| Hybrid securities | 615 | 479 | 273 |
| Other asset-backed securities | |||
| Hybrid Instruments [Line Items] | |||
| Hybrid securities | $ 0 | $ 1 | $ 5 |