Net Gains (Losses) Recorded in the Consolidated Statements of Income Relating to Free-Standing Derivative Instruments Used For Customer Accommodation (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Interest Rate Contract | Customer Contracts | Corporate Banking Revenue
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recorded in earnings	$ 5	$ 8	$ 14	$ 22
Interest Rate Contract | Customer Contracts | Other Noninterest Expense
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recorded in earnings			(1)	(3)
Interest Rate Contract | Fair Value Adjustments on Hedges and Derivative Contracts | Other Noninterest Expense
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recorded in earnings	1		2	4
Interest Rate Contract | Interest Rate Lock Commitments | Mortgage Banking Revenue
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recorded in earnings	18	43	92	41
Commodity Contract | Customer Contracts | Corporate Banking Revenue
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recorded in earnings	2	1	5	5
Commodity Contract | Fair Value Adjustments on Hedges and Derivative Contracts | Other Noninterest Expense
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recorded in earnings	1
Foreign Exchange Contract | Customer Contracts | Corporate Banking Revenue
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recorded in earnings	19	14	51	52
Foreign Exchange Contract | Fair Value Adjustments on Hedges and Derivative Contracts | Other Noninterest Expense
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recorded in earnings	$ (1)		$ 1	$ (2)