Loans and Allowance for Credit Losses - Summary of Loans by Portfolio Type and Deliquency Status (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	$ 234,454	$ 231,097
Accruing 30-89 Days Past Due	1,135	1,346
Accruing 90 Days or More Past Due	1,167	1,189
Nonperforming	1,619	1,603
Total loans, excluding covered loans	230,276	226,773
Total loans	238,375	235,235
Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	73,257	69,587
Accruing 30-89 Days Past Due	210	257
Accruing 90 Days or More Past Due	46	55
Nonperforming	188	134
Total loans, excluding covered loans	73,701	70,033
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	39,780	39,459
Accruing 30-89 Days Past Due	58	94
Accruing 90 Days or More Past Due	24	29
Nonperforming	269	303
Total loans, excluding covered loans	40,131	39,885
Residential Mortgages [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	50,294	49,695
Accruing 30-89 Days Past Due	306	358
Accruing 90 Days or More Past Due	331	333
Nonperforming	777	770
Total loans, excluding covered loans	51,708	51,156
Credit Card [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	16,653	17,507
Accruing 30-89 Days Past Due	203	226
Accruing 90 Days or More Past Due	208	210
Nonperforming	65	78
Total loans, excluding covered loans	17,129	18,021
Other Retail [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	47,131	47,156
Accruing 30-89 Days Past Due	202	245
Accruing 90 Days or More Past Due	86	86
Nonperforming	188	191
Total loans, excluding covered loans	47,607	47,678
Total Loans, Excluding Covered Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	227,115	223,404
Accruing 30-89 Days Past Due	979	1,180
Accruing 90 Days or More Past Due	695	713
Nonperforming	1,487	1,476
Total loans, excluding covered loans	230,276	226,773
Covered Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	7,339	7,693
Accruing 30-89 Days Past Due	156	166
Accruing 90 Days or More Past Due	472	476
Nonperforming	132	127
Total loans	$ 8,099	$ 8,462