Investments (Net Gains Losses on Trading Securities) (Details) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2026 |
Jun. 30, 2025 |
Jun. 30, 2026 |
Jun. 30, 2025 |
|
| Investments, Debt and Equity Securities [Abstract] | ||||
| Debt Securities, Trading, Unrealized Gain | $ (41) | $ 19 | $ (91) | $ 63 |
| Debt Securities, Trading, Realized Gain (Loss) | (1) | 3 | 0 | 6 |
| Net gains (losses) on trading securities | $ (42) | $ 22 | $ (91) | $ 69 |