Investment Securities (Summary Of Changes In Accumulated OCI For Available-For-Sale Security) (Details) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2026 |
Jun. 30, 2025 |
Jun. 30, 2026 |
Jun. 30, 2025 |
|
| Accumulated Other Comprehensive Income (Loss) [Roll Forward] | ||||
| Unrealized Gains and (Losses), Net | $ (7) | $ 48 | $ (15) | $ 141 |
| Agency Securities [Member] | ||||
| Accumulated Other Comprehensive Income (Loss) [Roll Forward] | ||||
| Beginning OCI Balance | (331) | (498) | (323) | (591) |
| Unrealized Gains and (Losses), Net | (7) | 34 | (21) | 127 |
| Reversal of Unrealized (Gains) and Losses, Net on Realization | 0 | 14 | 6 | 14 |
| Ending OCI Balance | $ (338) | $ (450) | $ (338) | $ (450) |