Derivative Instruments - Summary of Gains (Losses) Recognized in Earnings for Fair Value Hedges, Other Economic Hedges and Customer-Related Positions (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
Asset and Liability Management Positions [Member] | Other noninterest income [Member] | Other Derivatives [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	$ (43)		$ (43)
Asset and Liability Management Positions [Member] | Interest Rate Contracts [Member] | Other noninterest income [Member] | Fair Value Hedges [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	8	(5)	6	(7)
Asset and Liability Management Positions [Member] | Interest Rate Contracts [Member] | Mortgage banking revenue [Member] | Other Economic Hedges [Member] | Futures and Forwards [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	(26)	300	(75)	536
Asset and Liability Management Positions [Member] | Interest Rate Contracts [Member] | Mortgage banking revenue [Member] | Other Economic Hedges [Member] | Options [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	80	17	146	146
Asset and Liability Management Positions [Member] | Interest Rate Contracts [Member] | Mortgage banking revenue [Member] | Other Economic Hedges [Member] | Receive Fixed/Pay Floating Swaps [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	112	(219)	221	(259)
Asset and Liability Management Positions [Member] | Foreign Exchange Forward Contracts [Member] | Commercial products revenue [Member] | Other Economic Hedges [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	(12)	26	(17)	34
Asset and Liability Management Positions [Member] | Equity Contracts [Member] | Compensation expense [Member] | Other Economic Hedges [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	1	1	1	1
Asset and Liability Management Positions [Member] | Credit Contracts [Member] | Other noninterest income/expense [Member] | Other Economic Hedges [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings				(1)
Customer-Related Positions [Member] | Interest Rate Contracts [Member] | Other noninterest income [Member] | Receive Fixed/Pay Floating Swaps [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	215	(205)	349	(301)
Customer-Related Positions [Member] | Interest Rate Contracts [Member] | Other noninterest income [Member] | Pay Fixed/Receive Floating Swaps [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	(206)	212	(335)	308
Customer-Related Positions [Member] | Foreign Exchange Rate Contracts [Member] | Commercial products revenue [Member] | Forwards, Spots and Swaps [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings	$ 16	$ 14	$ 32	$ 21