Fair Value Measurements (Summary Of Quantitative Information About Level 3 Fair Value Measurements) (Details) - Discounted Cash Flow [Member] - Residential Mortgage [Member] $ in Millions |
Mar. 31, 2024
USD ($)
|
Dec. 31, 2023
USD ($)
|
|---|---|---|
| Level 3 [Member] | ||
| Fair Value Measurement Inputs and Valuation Techniques [Line Items] | ||
| Assets, Fair Value Disclosure | $ 1,026 | $ 906 |
| Recurring Fair Value Measurements [Member] | Minimum [Member] | ||
| Fair Value Measurement Inputs and Valuation Techniques [Line Items] | ||
| Weighted Average CPR | 0.039 | 0.056 |
| Option-Adjusted Spread | 4.60% | 4.50% |
| Recurring Fair Value Measurements [Member] | Maximum [Member] | ||
| Fair Value Measurement Inputs and Valuation Techniques [Line Items] | ||
| Weighted Average CPR | 0.280 | 0.215 |
| Option-Adjusted Spread | 8.20% | 8.20% |
| Recurring Fair Value Measurements [Member] | Weighted Average [Member] | ||
| Fair Value Measurement Inputs and Valuation Techniques [Line Items] | ||
| Weighted Average CPR | 0.082 | 0.082 |
| Option-Adjusted Spread | 4.90% | 4.80% |