Derivative Positions (Parenthetical) (Detail) (USD $) Share data in Millions, unless otherwise specified								1 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended
	Sep. 30, 2012 Nondesignated Trading Activity	Dec. 31, 2011 Nondesignated Trading Activity	Sep. 30, 2012 Derivative Financial Instruments, Assets Nondesignated Trading Activity	Dec. 31, 2011 Derivative Financial Instruments, Assets Nondesignated Trading Activity	Sep. 30, 2012 Derivative Financial Instruments, Assets Nondesignated Future	Sep. 30, 2012 Derivative Financial Instruments, Liabilities [Member] Nondesignated	Dec. 31, 2011 Derivative Financial Instruments, Liabilities [Member] Nondesignated Future	May 31, 2009 Derivative Financial Instruments, Liabilities [Member] Visa Interest Nondesignated	Dec. 31, 2011 Nondesignated	Sep. 30, 2012 Interest Income (Expense), Net [Member]	Sep. 30, 2011 Interest Income (Expense), Net [Member]	Sep. 30, 2012 Interest Income (Expense), Net [Member]	Sep. 30, 2011 Interest Income (Expense), Net [Member]	Sep. 30, 2012 Cash Flow Hedging	Sep. 30, 2011 Cash Flow Hedging	Sep. 30, 2012 Cash Flow Hedging	Sep. 30, 2011 Cash Flow Hedging
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net										$ 34,000,000	$ 56,000,000	$ 140,000,000	$ 146,000,000	$ (281,000,000)	$ 103,000,000	$ (115,000,000)	$ 321,000,000
Notional amounts related to interest rate futures			16,600,000,000	16,700,000,000	1,100,000,000		1,200,000,000
Notional related to equity futures			300,000,000	600,000,000
Asset amount notional from purchased and written interest rate swap risk participation agreements	2,000,000	2,000,000
Liability amount notional from purchased and written interest rate swap risk participation agreements	4,000,000	6,000,000
Derivative liability recorded in other liabilities, established upon the sale of Visa Class B shares						1,000,000			22,000,000
Notional amount, established upon the sale of Visa Class B shares						$ 134,000,000			$ 134,000,000
Shares of Class B Visa Inc. common stock sold to another financial institution, shares								3.2