Derivative Financial Instruments - Gains and Losses on Hedged Items in Fair Value Hedges (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
Derivative Instruments, Gain (Loss) [Line Items]
Net Ineffective Gain (Loss) Recognized - Other Income	$ 0	$ 1	$ 0	$ 0
Interest Income Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Derivative - Interest Income (Expense)	(62)	(51)	(121)	(103)
Gain (Loss) on Hedged Items - Interest Income (Expense)	95	96	182	195
Interest Income Expense [Member] | Interest rate contracts/AFS securities [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Derivative - Interest Income (Expense)	(64)	(55)	(127)	(111)
Gain (Loss) on Hedged Items - Interest Income (Expense)	96	111	198	225
Interest Income Expense [Member] | Interest rate contracts/subordinated debt [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Derivative - Interest Income (Expense)	2	4	6	8
Gain (Loss) on Hedged Items - Interest Income (Expense)	(1)	(15)	(16)	(30)
Other Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Derivative - Interest Income (Expense)	(188)	397	(408)	566
Gain (Loss) on Hedged Items - Interest Income (Expense)	189	(380)	402	(553)
Net Ineffective Gain (Loss) Recognized - Other Income	1	17	(6)	13
Other Income [Member] | Interest rate contracts/AFS securities [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Derivative - Interest Income (Expense)	(188)	397	(407)	567
Gain (Loss) on Hedged Items - Interest Income (Expense)	189	(380)	401	(554)
Net Ineffective Gain (Loss) Recognized - Other Income	1	17	(6)	13
Other Income [Member] | Interest rate contracts/subordinated debt [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Derivative - Interest Income (Expense)	0	0	(1)	(1)
Gain (Loss) on Hedged Items - Interest Income (Expense)	0	0	1	1
Net Ineffective Gain (Loss) Recognized - Other Income	$ 0	$ 0	$ 0	$ 0