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Fair Value Measurements (Fair Value Option, Fair Value and Unpaid Principal Balance) (Details) - Mortgage loans held for sale [Member] - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended |
--- | --- | --- | ---
Jun. 30, 2021 | Jun. 30, 2020 | Jun. 30, 2021 | Jun. 30, 2020 | Dec. 31, 2020
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |  |  |
Mortgages Held-for-sale, Fair Value Disclosure | $ 975 |  | $ 975 |  | $ 1,439
Fair Value Option Mortgages Held For Sale Aggregate Unpaid Principal | 939 |  | 939 |  | 1,362
Aggregate Fair Value Less Aggregate Unpaid Principal | 36 |  | 36 |  | $ 77
Net gains (losses) resulting from changes in fair value | $ 10 | $ 20 | $ (40) | $ 30 |

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- Definition This item represents the difference between the aggregate fair value and the aggregate unpaid principal balance of loans and long-term receivables (other than securities categorized as trading, available-for-sale or held-to-maturity) that have contractual principal amounts and for which the fair value option has been elected. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 28 -Subparagraph (d)(1) -URI http://asc.fasb.org/extlink&oid=75031198&loc=d3e14064-108612 + Details
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- Definition For each line item in the statement of financial position, the amounts of gains and losses from fair value changes included in earnings. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 30 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=75031198&loc=d3e14172-108612 + Details
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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- Definition Fair value portion of mortgage loans held-for-sale. + References No definition available. + Details
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- Details
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