Loans - TDR - Subsequent Defaults of Completed TDR Modifications (Detail) $ in Millions	12 Months Ended
Dec. 31, 2018 USD ($) Contract	Dec. 31, 2017 USD ($) Contract	Dec. 31, 2016 USD ($) Contract
Financing Receivable, Modifications [Line Items]
Number of Contracts \| Contract	129,120	116,523	91,597
Total Loans \| $	$ 437	$ 594	$ 550
Credit Card Portfolio Segment
Financing Receivable, Modifications [Line Items]
Number of Contracts \| Contract	122,084	106,762	82,748
Total Loans \| $	$ 232	$ 204	$ 155
Consumer Portfolio Segment
Financing Receivable, Modifications [Line Items]
Number of Contracts \| Contract	7,009	9,515	8,691
Total Loans \| $	$ 82	$ 120	$ 112
Consumer Portfolio Segment \| Auto
Financing Receivable, Modifications [Line Items]
Number of Contracts \| Contract	6,980	9,446	8,587
Total Loans \| $	$ 79	$ 109	$ 96
Consumer Portfolio Segment \| Home loan
Financing Receivable, Modifications [Line Items]
Number of Contracts \| Contract	3	28	56
Total Loans \| $	$ 1	$ 7	$ 7
Consumer Portfolio Segment \| Retail banking
Financing Receivable, Modifications [Line Items]
Number of Contracts \| Contract	26	41	48
Total Loans \| $	$ 2	$ 4	$ 9
Commercial Banking
Financing Receivable, Modifications [Line Items]
Number of Contracts \| Contract	27	246	158
Total Loans \| $	$ 123	$ 270	$ 283
Commercial Banking \| Total commercial lending
Financing Receivable, Modifications [Line Items]
Number of Contracts \| Contract	27	244	151
Total Loans \| $	$ 123	$ 269	$ 282
Commercial Banking \| Commercial and multifamily real estate
Financing Receivable, Modifications [Line Items]
Number of Contracts \| Contract	1	0	1
Total Loans \| $	$ 3	$ 0	$ 1
Commercial Banking \| Commercial and industrial
Financing Receivable, Modifications [Line Items]
Number of Contracts \| Contract	26	244	150
Total Loans \| $	$ 120	$ 269	$ 281
Commercial Banking \| Small-ticket commercial real estate
Financing Receivable, Modifications [Line Items]
Number of Contracts \| Contract	0	2	7
Total Loans \| $	$ 0	$ 1	$ 1
Domestic credit card \| Credit Card Portfolio Segment
Financing Receivable, Modifications [Line Items]
Number of Contracts \| Contract	61,070	55,121	42,250
Total Loans \| $	$ 126	$ 111	$ 73
International card business \| Credit Card Portfolio Segment
Financing Receivable, Modifications [Line Items]
Number of Contracts \| Contract	61,014	51,641	40,498
Total Loans \| $	$ 106	$ 93	$ 82

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Number of financing receivables that have been modified by troubled debt restructurings within the previous 12 months and for which there was a payment default.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 34
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953682-111524

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Amount of investment related to financing receivables modified by troubled debt restructurings within the previous 12 months, for which there was a payment default.

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