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Loans - TDR - Subsequent Defaults (Details) $ in Millions | 3 Months Ended
--- | ---
Mar. 31, 2021 USD ($) contract | Mar. 31, 2020 USD ($) contract
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |
Number of Contracts | contract | 24,372 | 30,025
Total Loans | $ | $ 67 | $ 92
Credit Card |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |
Number of Contracts | contract | 22,336 | 28,743
Total Loans | $ | $ 38 | $ 48
Consumer Banking |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |
Number of Contracts | contract | 2,036 | 1,276
Total Loans | $ | $ 29 | $ 16
Consumer Banking | Auto |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |
Number of Contracts | contract | 2,031 | 1,275
Total Loans | $ | $ 29 | $ 16
Consumer Banking | Retail banking |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |
Number of Contracts | contract | 5 | 1
Total Loans | $ | $ 0 | $ 0
Commercial Banking |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |
Number of Contracts | contract | 0 | 6
Total Loans | $ | $ 0 | $ 28
Commercial Banking | Commercial and industrial |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |
Number of Contracts | contract | 0 | 6
Total Loans | $ | $ 0 | $ 28
Domestic credit card: | Credit Card |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |
Number of Contracts | contract | 5,134 | 10,886
Total Loans | $ | $ 10 | $ 22
International card businesses: | Credit Card |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |
Number of Contracts | contract | 17,202 | 17,857
Total Loans | $ | $ 28 | $ 26

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- Definition Number of financing receivable contracts modified as troubled debt restructuring within previous 12 months, with subsequent payment default. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 34 -URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953682-111524 + Details
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