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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%

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- Definition Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482106/820-10-50-2 + Details
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- Definition Value of input used to measure servicing asset. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(2) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482106/820-10-50-2 + Details
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