Loans - Impaired Loans, Excluding Acquired Loans (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Impaired Financing Receivable:
With an Allowance	$ 1,442		$ 1,469
Without an Allowance	447		445
Total Recorded Investment	1,889		1,914
Related Allowance	289		300
Net Recorded Investment	1,600		1,614
Unpaid Principal Balance	2,274		2,296
Average Recorded Investment	1,901	1,968
Interest Income Recognized	40	40
Credit Card
Impaired Financing Receivable:
With an Allowance	673		692
Without an Allowance	0		0
Total Recorded Investment	673		692
Related Allowance	210		219
Net Recorded Investment	463		473
Unpaid Principal Balance	653		672
Average Recorded Investment	683	765
Interest Income Recognized	16	18
Credit Card \| Domestic
Impaired Financing Receivable:
With an Allowance	538		546
Without an Allowance	0		0
Total Recorded Investment	538		546
Related Allowance	143		145
Net Recorded Investment	395		401
Unpaid Principal Balance	523		531
Average Recorded Investment	542	596
Interest Income Recognized	14	15
Credit Card \| International
Impaired Financing Receivable:
With an Allowance	135		146
Without an Allowance	0		0
Total Recorded Investment	135		146
Related Allowance	67		74
Net Recorded Investment	68		72
Unpaid Principal Balance	130		141
Average Recorded Investment	141	169
Interest Income Recognized	2	3
Consumer Banking
Impaired Financing Receivable:
With an Allowance	514		493
Without an Allowance	358		359
Total Recorded Investment	872		852
Related Allowance	47		42
Net Recorded Investment	825		810
Unpaid Principal Balance	1,241		1,218
Average Recorded Investment	862	848
Interest Income Recognized	22	19
Consumer Banking \| Auto
Impaired Financing Receivable:
With an Allowance	249		230
Without an Allowance	204		205
Total Recorded Investment	453		435
Related Allowance	22		19
Net Recorded Investment	431		416
Unpaid Principal Balance	717		694
Average Recorded Investment	444	363
Interest Income Recognized	21	17
Consumer Banking \| Home loan
Impaired Financing Receivable:
With an Allowance	219		218
Without an Allowance	146		149
Total Recorded Investment	365		367
Related Allowance	16		17
Net Recorded Investment	349		350
Unpaid Principal Balance	467		472
Average Recorded Investment	366	402
Interest Income Recognized	1	1
Consumer Banking \| Retail banking
Impaired Financing Receivable:
With an Allowance	46		45
Without an Allowance	8		5
Total Recorded Investment	54		50
Related Allowance	9		6
Net Recorded Investment	45		44
Unpaid Principal Balance	57		52
Average Recorded Investment	52	83
Interest Income Recognized	0	1
Commercial Banking
Impaired Financing Receivable:
With an Allowance	255		284
Without an Allowance	89		86
Total Recorded Investment	344		370
Related Allowance	32		39
Net Recorded Investment	312		331
Unpaid Principal Balance	380		406
Average Recorded Investment	356	355
Interest Income Recognized	2	3
Commercial Banking \| Total commercial lending
Impaired Financing Receivable:
With an Allowance	251		281
Without an Allowance	80		81
Total Recorded Investment	331		362
Related Allowance	32		39
Net Recorded Investment	299		323
Unpaid Principal Balance	365		396
Average Recorded Investment	346	348
Interest Income Recognized	2	3
Commercial Banking \| Commercial and multifamily real estate
Impaired Financing Receivable:
With an Allowance	107		120
Without an Allowance	13		26
Total Recorded Investment	120		146
Related Allowance	19		23
Net Recorded Investment	101		123
Unpaid Principal Balance	134		163
Average Recorded Investment	133	169
Interest Income Recognized	1	2
Commercial Banking \| Commercial and industrial
Impaired Financing Receivable:
With an Allowance	144		161
Without an Allowance	67		55
Total Recorded Investment	211		216
Related Allowance	13		16
Net Recorded Investment	198		200
Unpaid Principal Balance	231		233
Average Recorded Investment	213	179
Interest Income Recognized	1	1
Commercial Banking \| Small-ticket commercial real estate
Impaired Financing Receivable:
With an Allowance	4		3
Without an Allowance	9		5
Total Recorded Investment	13		8
Related Allowance	0		0
Net Recorded Investment	13		8
Unpaid Principal Balance	15		10
Average Recorded Investment	10	7
Interest Income Recognized	$ 0	$ 0

Impaired Financing Receivable, Interest Income, Accrual Method and Cash Method

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- Definition

Impaired Financing Receivable, Recorded Investment, Net of Related Allowance

+ References

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- Definition

Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 15

-Subparagraph (c)(1)

-URI http://asc.fasb.org/extlink&oid=35738203&loc=d3e5212-111524

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 17

-URI http://asc.fasb.org/extlink&oid=35738203&loc=d3e5258-111524

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Amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 14A

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=35738203&loc=SL6953550-111524

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Amount of allowance for credit losses related to recorded investment.

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Amount of unpaid principal balance of impaired financing receivables with related allowance for credit losses and without related allowance for credit losses.

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- Definition

Amount of investment in impaired financing receivables for which there is no related allowance for credit losses.

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- Definition

Amount of investment in impaired financing receivables for which there is a related allowance for credit losses.

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