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Pledged Assets - Additional Information (Detail) (USD $)
3 Months Ended
Mar. 31, 2013
Mar. 31, 2012
Dec. 31, 2012
Financial Instruments Owned and Pledged as Collateral [Line Items]      
Amount of securities and loans pledged $ 26,700,000,000   $ 27,200,000,000
Fair value of accepted collateral 250,000,000   35,400,000
Amount of securities repledged or sold collateral 0   0
Average deposits maintained to meet Federal Reserve Bank reserve requirements 900,000,000 1,100,000,000  
US Government Corporations and Agencies Securities
     
Financial Instruments Owned and Pledged as Collateral [Line Items]      
Amount of securities and loans pledged 18,600,000,000   19,000,000,000
Obligations of States and Political Subdivisions
     
Financial Instruments Owned and Pledged as Collateral [Line Items]      
Amount of securities and loans pledged 296,300,000   334,000,000
Loans
     
Financial Instruments Owned and Pledged as Collateral [Line Items]      
Amount of securities and loans pledged 7,800,000,000   7,900,000,000
Collateral Requirements
     
Financial Instruments Owned and Pledged as Collateral [Line Items]      
Amount of securities and loans pledged 4,800,000,000   3,400,000,000
Available for Sale Investment Securities
     
Financial Instruments Owned and Pledged as Collateral [Line Items]      
Amount of securities and loans pledged $ 480,100,000   $ 690,100,000