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Loans - TDR - Subsequent Defaults of Completed TDR Modifications (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($) Contract	Dec. 31, 2018 USD ($) Contract	Dec. 31, 2017 USD ($) Contract
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts | Contract	122,156	129,120	116,523
Total Loans | $	$ 306	$ 437	$ 594
Credit Card
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts | Contract	116,556	122,084	106,762
Total Loans | $	$ 209	$ 232	$ 204
Consumer Banking
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts | Contract	5,599	7,009	9,515
Total Loans | $	$ 72	$ 82	$ 120
Consumer Banking | Auto
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts | Contract	5,575	6,980	9,446
Total Loans | $	$ 70	$ 79	$ 109
Consumer Banking | Home loan
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts | Contract	0	3	28
Total Loans | $	$ 0	$ 1	$ 7
Consumer Banking | Retail banking
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts | Contract	24	26	41
Total Loans | $	$ 2	$ 2	$ 4
Commercial Banking
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts | Contract	1	27	246
Total Loans | $	$ 25	$ 123	$ 270
Commercial Banking | Total commercial lending
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts | Contract	1	27	244
Total Loans | $	$ 25	$ 123	$ 269
Commercial Banking | Commercial and multifamily real estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts | Contract	0	1	0
Total Loans | $	$ 0	$ 3	$ 0
Commercial Banking | Commercial and industrial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts | Contract	1	26	244
Total Loans | $	$ 25	$ 120	$ 269
Commercial Banking | Small-ticket commercial real estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts | Contract	0	0	2
Total Loans | $	$ 0	$ 0	$ 1
Domestic credit card | Credit Card
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts | Contract	47,086	61,070	55,121
Total Loans | $	$ 99	$ 126	$ 111
International card business | Credit Card
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts | Contract	69,470	61,014	51,641
Total Loans | $	$ 110	$ 106	$ 93

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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=118936363&loc=SL6953682-111524

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+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 34
-Subparagraph (a)(2)
-URI http://asc.fasb.org/extlink&oid=118936363&loc=SL6953682-111524

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