Loans and Allowance for Credit Losses - Summary of Loans by Portfolio Type and Deliquency Status (Detail) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	$ 240,228	$ 231,097
Accruing 30-89 Days Past Due	1,012	1,346
Accruing 90 Days or More Past Due	1,038	1,189
Nonperforming	1,596	1,603
Total loans, excluding covered loans	236,426	226,773
Total loans	243,874	235,235
Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	77,018	69,587
Accruing 30-89 Days Past Due	202	257
Accruing 90 Days or More Past Due	44	55
Nonperforming	190	134
Total loans, excluding covered loans	77,454	70,033
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	40,489	39,459
Accruing 30-89 Days Past Due	56	94
Accruing 90 Days or More Past Due	26	29
Nonperforming	226	303
Total loans, excluding covered loans	40,797	39,885
Residential Mortgages [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	50,643	49,695
Accruing 30-89 Days Past Due	251	358
Accruing 90 Days or More Past Due	253	333
Nonperforming	818	770
Total loans, excluding covered loans	51,965	51,156
Credit Card [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	17,204	17,507
Accruing 30-89 Days Past Due	199	226
Accruing 90 Days or More Past Due	187	210
Nonperforming	52	78
Total loans, excluding covered loans	17,642	18,021
Other Retail [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	48,093	47,156
Accruing 30-89 Days Past Due	213	245
Accruing 90 Days or More Past Due	71	86
Nonperforming	191	191
Total loans, excluding covered loans	48,568	47,678
Total Loans, Excluding Covered Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	233,447	223,404
Accruing 30-89 Days Past Due	921	1,180
Accruing 90 Days or More Past Due	581	713
Nonperforming	1,477	1,476
Total loans, excluding covered loans	236,426	226,773
Covered Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	6,781	7,693
Accruing 30-89 Days Past Due	91	166
Accruing 90 Days or More Past Due	457	476
Nonperforming	119	127
Total loans	$ 7,448	$ 8,462