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) (USD $) In Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Gain and losses included in earnings	$ 89	$ 92	$ 158	$ 202
Mortgage Banking Revenue [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Gain and losses included in earnings	104	101	159	210
Other Noninterest Income [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Gain and losses included in earnings	(15)	(10)	(2)	(12)
Gain (Loss) on Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Gain and losses included in earnings				3
Corporate Banking Revenue [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Gain and losses included in earnings		$ 1	$ 1	$ 1