Stockholders' Equity - Reclassification from AOCI (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other - Non-interest income	$ 96	$ 140	$ 176	$ 458
Other - Non-interest expense	(592)	(618)	(1,623)	(1,762)
Income tax benefit	525	535	1,600	931
Net income	1,117	1,178	3,300	2,674
Total reclassifications	1,099	1,173	3,247	2,662
Reclassification Out of AOCI [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total reclassifications	5		23
Reclassification Out of AOCI [Member] | Accumulated Net Unrealized Investment Gain (Loss) [Member] | Securities Available for Sale [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other - Non-interest income	0		3
Income tax benefit	0		1
Net income	0		2
Reclassification Out of AOCI [Member] | Accumulated Net Unrealized Investment Gain (Loss) [Member] | Securities Held-to-Maturity [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other - Non-interest income	(2)		(2)
Income tax benefit	(1)		(1)
Net income	(1)		(1)
Reclassification Out of AOCI [Member] | Cash Flow Hedges [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income before tax	10		38
Income tax benefit	4		15
Net income	6		23
Reclassification Out of AOCI [Member] | Cash Flow Hedges [Member] | Interest Rate Contracts [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other - Non-interest income	23		65
Reclassification Out of AOCI [Member] | Cash Flow Hedges [Member] | Foreign Exchange Contracts [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other - Non-interest expense	(13)		(27)
Reclassification Out of AOCI [Member] | Accumulated Defined Benefit Plans Adjustment [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Salaries and associate benefits	0		(1)
Income tax benefit	0		0
Net income	$ 0		$ (1)