Total Gains and Losses Included in Earnings for Assets and Liabilites Measured at Fair Value on a Recurring Basis Using Significant Unobservable Inputs (Level 3) (Detail) (Fair Value, Inputs, Level 3, USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation
Gains and losses included in earnings	$ 86	$ 12	$ 90	$ 96
Mortgage Banking Revenue
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation
Gains and losses included in earnings	39	(59)	76	(2)
Other Noninterest Income
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation
Gains and losses included in earnings	47	71	13	98
Corporate Banking Revenue
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation
Gains and losses included in earnings			$ 1