Investments - Schedule of Impaired Residential Mortgage Loans (Details) - USD ($) $ in Millions |
Sep. 30, 2026 |
Dec. 31, 2025 |
|---|---|---|
| Investments, Debt and Equity Securities [Abstract] | ||
| Recorded investment | $ 24 | $ 38 |
| Unpaid principal balance | 26 | 45 |
| Related loan allowance | 0 | 1 |
| Average recorded investment | 28 | 29 |
| Investment income recognized | 0 | 1 |
| Mortgage loans in process of foreclosure | $ 4 | $ 4 |