Fair Value (Carrying amount and estimated fair value of financial instrument assets and liabilities which are not measured at fair value) (Details) - USD ($) $ in Millions |
Mar. 31, 2025 |
Dec. 31, 2024 |
|---|---|---|
| Assets | ||
| Mortgage loans | $ 1,049 | $ 1,019 |
| Liabilities | ||
| Long-term debt | 2,474 | 2,973 |
| Carrying Amount | ||
| Assets | ||
| Mortgage loans | 1,049 | 1,019 |
| Liabilities | ||
| Short-term debt | 500 | 0 |
| Long-term debt | 2,474 | 2,973 |
| Estimated Fair Value | ||
| Assets | ||
| Mortgage loans | 1,035 | 987 |
| Liabilities | ||
| Short-term debt | 499 | 0 |
| Long-term debt | 2,410 | 2,885 |
| Level 1 | Estimated Fair Value | ||
| Assets | ||
| Mortgage loans | 0 | 0 |
| Liabilities | ||
| Short-term debt | 0 | 0 |
| Long-term debt | 0 | 0 |
| Level 2 | Estimated Fair Value | ||
| Assets | ||
| Mortgage loans | 0 | 0 |
| Liabilities | ||
| Short-term debt | 499 | 0 |
| Long-term debt | 2,410 | 2,885 |
| Level 3 | Estimated Fair Value | ||
| Assets | ||
| Mortgage loans | 1,035 | 987 |
| Liabilities | ||
| Short-term debt | 0 | 0 |
| Long-term debt | $ 0 | $ 0 |