Investments - Schedule of Carrying Value for Limited Partnership Interests (Details) - USD ($) $ in Millions |
Jun. 30, 2025 |
Dec. 31, 2024 |
|---|---|---|
| Debt and Equity Securities, FV-NI [Line Items] | ||
| Limited partnership interests | $ 9,194 | $ 9,255 |
| Private equity | ||
| Debt and Equity Securities, FV-NI [Line Items] | ||
| Limited partnership interests | 7,578 | 7,734 |
| Real estate | ||
| Debt and Equity Securities, FV-NI [Line Items] | ||
| Limited partnership interests | 1,405 | 1,236 |
| Other | ||
| Debt and Equity Securities, FV-NI [Line Items] | ||
| Limited partnership interests | $ 211 | $ 285 |