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Derivative Instruments and Hedging Activities - Gains Losses on Freestanding Derivatives (Details) - Other non-interest income - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2021 | Sep. 30, 2020 | Sep. 30, 2021 | Sep. 30, 2020
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Gains (losses) on derivatives not designated as accounting hedges | $ 33 | $ 20 | $ 51 | $ 36
Interest rate contracts |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Gains (losses) on derivatives not designated as accounting hedges | 21 | 3 | 56 | 35
Interest rate contracts | Customer accommodation |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Gains (losses) on derivatives not designated as accounting hedges | 7 | (5) | 25 | 7
Interest rate contracts | Other interest rate exposures |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Gains (losses) on derivatives not designated as accounting hedges | 18 | 17 | 2 | 1
Commodity contracts | Customer accommodation |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Gains (losses) on derivatives not designated as accounting hedges | 11 | 7 | 20 | 23
Foreign exchange contracts | Customer accommodation |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Gains (losses) on derivatives not designated as accounting hedges | 3 | 1 | 11 | 5
Other contracts |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Gains (losses) on derivatives not designated as accounting hedges | (6) | $ 0 | (7) | $ 0
FX spot transactions | Customer accommodation |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Gains (losses) on derivatives not designated as accounting hedges | $ 1 |  | $ 8 |

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- Definition Amount of realized and unrealized gain (loss) of derivative instruments not designated or qualifying as hedging instruments. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4CC -URI http://asc.fasb.org/extlink&oid=125515794&loc=SL109998890-113959 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4C -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=125515794&loc=SL5624171-113959 + Details
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