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	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Interest Rate Contract | Customer Contracts | Corporate Banking Revenue
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recorded in earnings	$ 19	$ 29	$ 30
Interest Rate Contract | Customer Contracts | Other Noninterest Expense
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recorded in earnings	(3)	(3)	(2)
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	3	7	6
Interest Rate Contract | Interest Rate Lock Commitments | Mortgage Banking Revenue
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recorded in earnings	124	58	417
Commodity Contract | Customer Contracts | Corporate Banking Revenue
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recorded in earnings	6	7	7
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	(7)		2
Foreign Exchange Contract | Customer Contracts | Corporate Banking Revenue
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recorded in earnings	72	69	65
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		$ (2)	$ 2