Fair Value of the Servicing Assets (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013	Dec. 31, 2012
Servicing Assets at Fair Value
Fair value at beginning of period			$ 6
Fair value at end of period			6
Fixed Rate Residential Mortgage
Servicing Assets at Fair Value
Fair value at beginning of period	935	929	731	664
Fair value at end of period	935	929	731	664
Adjustable Rate Residential Mortgage
Servicing Assets at Fair Value
Fair value at beginning of period	37	38	35	33
Fair value at end of period	37	38	35	33
Fixed Rate Automobile Loans
Servicing Assets at Fair Value
Fair value at beginning of period	3	4	6
Fair value at end of period	$ 3	$ 4	$ 6