Fair Value of Assets and Liabilities (Nonrecurring Fair Value Measurements) (Details) - Fair Value, Measurements, Nonrecurring - Level 3 - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | |||
|---|---|---|---|---|---|
Jun. 30, 2025 |
Jun. 30, 2024 |
Jun. 30, 2025 |
Jun. 30, 2024 |
Dec. 31, 2024 |
|
| Investment real estate | |||||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | |||||
| Realized investment gains (losses) net | $ 0 | $ (3) | $ (12) | $ (3) | |
| Carrying value after measurement as of period end | 46 | 46 | $ 73 | ||
| Investment in JV/LP and Other | |||||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | |||||
| Realized investment gains (losses) net | 0 | $ 0 | 0 | $ (7) | |
| Carrying value after measurement as of period end | $ 0 | $ 0 | $ 128 | ||