Changes in the Servicing Assets (Detail) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Servicing Assets at Fair Value
Carrying amount before valuation allowance as of the beginning of the period	$ 1,440	$ 1,358
Servicing rights that result from the transfer of residential mortgage or automobile loans	44	150
Amortization	(56)	(105)
Carrying amount before valuation allowance	1,428	1,409
Valuation allowance for servicing assets:
Beginning balance	(469)	(661)
(Provision for) recovery of MSR impairment	(28)	151
Ending balance	(497)	(510)
Carrying amount as of the end of the period	931	899
Automobile Loan Securitizations
Servicing Assets at Fair Value
Servicing rights that result from the transfer of residential mortgage or automobile loans		$ 6