Derivative Positions (Parenthetical) (Detail) (Nondesignated, USD $) Share data in Millions, unless otherwise specified									1 Months Ended
	Dec. 31, 2012 Trading Activity	Dec. 31, 2011 Trading Activity	Dec. 31, 2012 Derivative Financial Instruments, Assets Trading Activity	Dec. 31, 2011 Derivative Financial Instruments, Assets Trading Activity	Dec. 31, 2012 Derivative Financial Instruments, Liabilities [Member]	Dec. 31, 2011 Derivative Financial Instruments, Liabilities [Member]	Dec. 31, 2012 Derivative Financial Instruments, Liabilities [Member] Future	Dec. 31, 2011 Derivative Financial Instruments, Liabilities [Member] Future	May 31, 2009 Derivative Financial Instruments, Liabilities [Member] Visa Interest
Notional amounts related to interest rate futures			$ 16,200,000,000	$ 16,700,000,000			$ 1,700,000,000	$ 1,200,000,000
Notional related to equity futures			800,000,000	600,000,000
Asset amount notional from purchased and written interest rate swap risk participation agreements	3,000,000	2,000,000
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
Liability amount notional from purchased and written interest rate swap risk participation agreements	$ 3,000,000	$ 6,000,000