MSR (Fair Value of the Servicing Rights) (Detail) - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2015
Fixed Rate Residential Mortgage Loans
Servicing Assets at Fair Value
Fair value at beginning of period	$ 757	$ 826	$ 823
Fair value at end of period	598	757	826
Adjustable Rate Residential Mortgage Loans
Servicing Assets at Fair Value
Fair value at beginning of period	27	27	33
Fair value at end of period	23	27	27
Fixed Rate Automobile Loans
Servicing Assets at Fair Value
Fair value at beginning of period	$ 1	1	2
Fair value at end of period		$ 1	$ 1