Fair Value Measurements And Disclosure (Gain and Losses on Equity Securities) (Details) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2025 |
Jun. 30, 2024 |
Jun. 30, 2025 |
Jun. 30, 2024 |
|
| Fair Value Disclosures [Abstract] | ||||
| Total gains (losses) recognized on equity securities | $ 48 | $ 29 | $ 21 | $ 126 |
| Gains (losses) recognized on equity securities sold | 0 | (5) | 0 | (8) |
| Unrealized gains (losses) recognized on equity securities held at end of period | $ 48 | $ 34 | $ 21 | $ 134 |