Changes in the Servicing Assets (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Servicing Assets at Fair Value [Line Items]
Carrying amount as of the beginning of the period	$ 1,358	$ 1,239
Servicing obligations that result from the transfer of residential mortgage loans	244	305
Servicing Asset At Amortized Value Amortization	(168)	(186)	(135)
Carrying amount before valuation allowance	1,440	1,358	1,239
Valuation allowance for servicing assets:
Beginning balance	(661)	(558)
Servicing impairment	192	(103)
Ending balance	(469)	(661)	(558)
Carrying amount as of the end of the period	971	697
Automobile Loan Securitizations
Servicing Assets at Fair Value [Line Items]
Servicing obligations that result from the transfer of residential mortgage loans	$ (6)