Segment Information (Narrative) (Detail) (USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Segment Reporting Information [Line Items]
Restructuring expense	$ 10,000,000	$ 7,000,000
Assets under vehicle programs	10,864,000,000		10,099,000,000
Non current deferred tax assets	1,346,000,000		1,454,000,000
North America [Member]
Segment Reporting Information [Line Items]
Restructuring expense	3,000,000
Assets under vehicle programs	8,300,000,000	7,400,000,000
Segment Assets Exclusive Of Assets Under Vehicle Program	3,600,000,000	3,100,000,000
International [Member]
Segment Reporting Information [Line Items]
Restructuring expense	$ 3,000,000