Segment Information (Narrative) (Detail) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Segment Reporting Information [Line Items]
Assets under vehicle programs	$ 11,381	$ 9,090
Non current deferred tax assets	1,265	444
North America [Member]
Segment Reporting Information [Line Items]
Assets under vehicle programs	8,300	6,700
Non current deferred tax assets	1,200	401
International [Member]
Segment Reporting Information [Line Items]
Assets under vehicle programs	$ 2,700	$ 2,100