Fair Value of Assets and Liabilities (Nonrecurring Fair Value Measurements) (Details) - Fair Value, Measurements, Nonrecurring - Level 3 - USD ($) $ in Millions |
3 Months Ended | ||
|---|---|---|---|
Mar. 31, 2026 |
Mar. 31, 2025 |
Dec. 31, 2025 |
|
| Investment real estate | |||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | |||
| Realized investment gains (losses) net | $ 0 | $ (12) | |
| Carrying value after measurement as of period end | 0 | $ 45 | |
| Investment in JV/LP and Other | |||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | |||
| Realized investment gains (losses) net | (5) | 0 | |
| Carrying value after measurement as of period end | 74 | 61 | |
| Equity securities | |||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | |||
| Realized investment gains (losses) net | 9 | $ 0 | |
| Carrying value after measurement as of period end | $ 32 | $ 92 | |