Loans - Individually Impaired Loans, Excluding Acquired Loans (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Impaired Financing Receivable:
With an Allowance	$ 1,462		$ 1,462		$ 1,424
Without an Allowance	419		419		520
Total Recorded Investment	1,881		1,881		1,944
Related Allowance	294		294		330
Net Recorded Investment	1,587		1,587		1,614
Unpaid Principal Balance	2,262		2,262		2,402
Average Recorded Investment	1,926	1,855	1,950	1,916
Interest Income Recognized	40	39	119	112
Credit Card
Impaired Financing Receivable:
With an Allowance	706		706		780
Without an Allowance	0		0		0
Total Recorded Investment	706		706		780
Related Allowance	222		222		261
Net Recorded Investment	484		484		519
Unpaid Principal Balance	685		685		757
Average Recorded Investment	717	795	741	825
Interest Income Recognized	17	19	53	58
Credit Card | Domestic
Impaired Financing Receivable:
With an Allowance	553		553		609
Without an Allowance	0		0		0
Total Recorded Investment	553		553		609
Related Allowance	142		142		154
Net Recorded Investment	411		411		455
Unpaid Principal Balance	538		538		593
Average Recorded Investment	558	627	577	656
Interest Income Recognized	14	16	44	50
Credit Card | International
Impaired Financing Receivable:
With an Allowance	153		153		171
Without an Allowance	0		0		0
Total Recorded Investment	153		153		171
Related Allowance	80		80		107
Net Recorded Investment	73		73		64
Unpaid Principal Balance	147		147		164
Average Recorded Investment	159	168	164	169
Interest Income Recognized	3	3	9	8
Consumer Banking
Impaired Financing Receivable:
With an Allowance	470		470		459
Without an Allowance	340		340		376
Total Recorded Investment	810		810		835
Related Allowance	40		40		44
Net Recorded Investment	770		770		791
Unpaid Principal Balance	1,171		1,171		1,256
Average Recorded Investment	829	635	841	608
Interest Income Recognized	20	19	58	53
Consumer Banking | Auto
Impaired Financing Receivable:
With an Allowance	204		204		169
Without an Allowance	195		195		186
Total Recorded Investment	399		399		355
Related Allowance	18		18		16
Net Recorded Investment	381		381		339
Unpaid Principal Balance	648		648		590
Average Recorded Investment	387	332	375	330
Interest Income Recognized	18	16	52	46
Consumer Banking | Home loan
Impaired Financing Receivable:
With an Allowance	220		220		244
Without an Allowance	140		140		150
Total Recorded Investment	360		360		394
Related Allowance	16		16		18
Net Recorded Investment	344		344		376
Unpaid Principal Balance	469		469		561
Average Recorded Investment	382	211	392	184
Interest Income Recognized	1	2	4	5
Consumer Banking | Retail banking
Impaired Financing Receivable:
With an Allowance	46		46		46
Without an Allowance	5		5		40
Total Recorded Investment	51		51		86
Related Allowance	6		6		10
Net Recorded Investment	45		45		76
Unpaid Principal Balance	54		54		105
Average Recorded Investment	60	92	74	94
Interest Income Recognized	1	1	2	2
Commercial Banking
Impaired Financing Receivable:
With an Allowance	286		286		185
Without an Allowance	79		79		144
Total Recorded Investment	365		365		329
Related Allowance	32		32		25
Net Recorded Investment	333		333		304
Unpaid Principal Balance	406		406		389
Average Recorded Investment	380	425	368	483
Interest Income Recognized	3	1	8	1
Commercial Banking | Total commercial lending
Impaired Financing Receivable:
With an Allowance	285		285		183
Without an Allowance	75		75		140
Total Recorded Investment	360		360		323
Related Allowance	32		32		25
Net Recorded Investment	328		328		298
Unpaid Principal Balance	401		401		382
Average Recorded Investment	371	411	360	464
Interest Income Recognized	3	1	8	1
Commercial Banking | Commercial and multifamily real estate
Impaired Financing Receivable:
With an Allowance	166		166		89
Without an Allowance	25		25		49
Total Recorded Investment	191		191		138
Related Allowance	21		21		13
Net Recorded Investment	170		170		125
Unpaid Principal Balance	211		211		162
Average Recorded Investment	196	195	183	237
Interest Income Recognized	2	0	5	0
Commercial Banking | Commercial and industrial
Impaired Financing Receivable:
With an Allowance	119		119		94
Without an Allowance	50		50		91
Total Recorded Investment	169		169		185
Related Allowance	11		11		12
Net Recorded Investment	158		158		173
Unpaid Principal Balance	190		190		220
Average Recorded Investment	175	216	177	227
Interest Income Recognized	1	1	3	1
Commercial Banking | Small-ticket commercial real estate
Impaired Financing Receivable:
With an Allowance	1		1		2
Without an Allowance	4		4		4
Total Recorded Investment	5		5		6
Related Allowance	0		0		0
Net Recorded Investment	5		5		6
Unpaid Principal Balance	5		5		7
Average Recorded Investment	9	14	8	19
Interest Income Recognized	$ 0	$ 0	$ 0	$ 0