Loans and Allowance for Credit Losses - Impaired Loans Average Recorded Investment and Interest Income (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	$ 7,603	$ 7,349	$ 7,609	$ 7,455
Interest Income Recognized	88	94	179	189
Commercial [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	447	381	432	386
Interest Income Recognized	2	9	4	19
Commercial Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	592	975	626	1,015
Interest Income Recognized	4	10	13	21
Residential Mortgages [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	2,739	2,738	2,746	2,733
Interest Income Recognized	37	33	72	67
Credit Card [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	281	376	290	397
Interest Income Recognized	3	5	6	9
Other Retail [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	381	435	385	439
Interest Income Recognized	4	6	8	12
Total Impaired Loans, Excluding GNMA and Covered Loans [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	4,440	4,905	4,479	4,970
Interest Income Recognized	50	63	103	128
Loans Purchased from GNMA Mortgage Pools [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	2,766	1,880	2,714	1,862
Interest Income Recognized	33	23	66	46
Covered Loans [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	397	564	416	623
Interest Income Recognized	$ 5	$ 8	$ 10	$ 15