Mortgage Servicing Rights - Additional Information (Detail) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Transfers And Servicing Of Financial Assets [Abstract]
Residential mortgage loans serviced for others including subserviced mortgages with no corresponding MSRs asset	$ 224,700,000,000		$ 224,700,000,000		$ 226,800,000,000
Gain/Loss on fair value changes of MSRs due to changes in valuation assumptions and derivatives used to economically hedge MSRs	93,000,000	13,000,000	151,000,000	54,000,000
Loan servicing fees	185,000,000	187,000,000	373,000,000	374,000,000
Gain related to excess servicing rights sold	$ 44,000,000