Net Gains (Losses) Recorded in the Consolidated Statements of Income Relating to Free-Standing Derivative Instruments Used For Customer Accommodation (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Interest Rate Contract | Customer Contracts | Corporate Banking Revenue
Derivative Instruments, Gain (Loss)
Net gains (losses) recorded in earnings	$ 7	$ 6
Interest Rate Contract | Fair Value Adjustments on Hedges and Derivative Contracts | Other noninterest expense
Derivative Instruments, Gain (Loss)
Net gains (losses) recorded in earnings	(1)	(1)
Interest Rate Contract | Interest Rate Lock Commitments | Mortgage Banking Revenue
Derivative Instruments, Gain (Loss)
Net gains (losses) recorded in earnings	42	35
Commodity Contract | Customer Contracts | Corporate Banking Revenue
Derivative Instruments, Gain (Loss)
Net gains (losses) recorded in earnings	1	1
Commodity Contract | Customer Contracts | Other noninterest expense
Derivative Instruments, Gain (Loss)
Net gains (losses) recorded in earnings		(2)
Commodity Contract | Fair Value Adjustments on Hedges and Derivative Contracts | Other noninterest expense
Derivative Instruments, Gain (Loss)
Net gains (losses) recorded in earnings	(1)	5
Foreign Exchange Contract | Customer Contracts | Corporate Banking Revenue
Derivative Instruments, Gain (Loss)
Net gains (losses) recorded in earnings	16	21
Foreign Exchange Contract | Fair Value Adjustments on Hedges and Derivative Contracts | Other noninterest expense
Derivative Instruments, Gain (Loss)
Net gains (losses) recorded in earnings	$ (2)	$ (1)