Loans - TDR - Subsequent Defaults of Completed TDR Modifications (Detail) $ in Millions	3 Months Ended
Mar. 31, 2017 USD ($) Contract	Mar. 31, 2016 USD ($) Contract
Financing Receivable, Modifications [Line Items]
Number of Contracts \| Contract	26,446	21,301
Total Loans \| $	$ 91	$ 85
Credit Card Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts \| Contract	24,230	19,407
Total Loans \| $	$ 42	$ 38
Consumer Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts \| Contract	2,201	1,877
Total Loans \| $	$ 29	$ 24
Consumer Portfolio Segment [Member] \| Auto
Financing Receivable, Modifications [Line Items]
Number of Contracts \| Contract	2,179	1,852
Total Loans \| $	$ 25	$ 21
Consumer Portfolio Segment [Member] \| Home loan
Financing Receivable, Modifications [Line Items]
Number of Contracts \| Contract	11	10
Total Loans \| $	$ 3	$ 1
Consumer Portfolio Segment [Member] \| Retail banking
Financing Receivable, Modifications [Line Items]
Number of Contracts \| Contract	11	15
Total Loans \| $	$ 1	$ 2
Commercial Banking
Financing Receivable, Modifications [Line Items]
Number of Contracts \| Contract	15	17
Total Loans \| $	$ 20	$ 23
Commercial Banking \| Total commercial lending
Financing Receivable, Modifications [Line Items]
Number of Contracts \| Contract	14	17
Total Loans \| $	$ 19	$ 23
Commercial Banking \| Commercial and multifamily real estate
Financing Receivable, Modifications [Line Items]
Number of Contracts \| Contract	0	0
Total Loans \| $	$ 0	$ 0
Commercial Banking \| Commercial and industrial
Financing Receivable, Modifications [Line Items]
Number of Contracts \| Contract	14	17
Total Loans \| $	$ 19	$ 23
Commercial Banking \| Small-ticket commercial real estate
Financing Receivable, Modifications [Line Items]
Number of Contracts \| Contract	1	0
Total Loans \| $	$ 1	$ 0
Geographic Distribution, Domestic [Member] \| Credit Card Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts \| Contract	12,805	10,594
Total Loans \| $	$ 26	$ 18
Geographic Distribution, Foreign [Member] \| Credit Card Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts \| Contract	11,425	8,813
Total Loans \| $	$ 16	$ 20

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- Definition

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://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 34
-URI http://asc.fasb.org/extlink&oid=66008989&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.

+ References

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