Summary of Geographic Segment Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	$ 7,357	$ 5,900	$ 5,185
Assets exclusive of assets under vehicle programs	5,119	3,848	3,462
Assets under vehicle programs	10,099	9,090	6,865
Property and equipment, net	529	493	425
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	4,637	4,489	4,263
Assets exclusive of assets under vehicle programs	3,094	2,177	2,949
Assets under vehicle programs	7,329	6,553	5,899
Property and equipment, net	366	365	382
All Other Countries
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	2,720	1,411	922
Assets exclusive of assets under vehicle programs	2,025	1,671	513
Assets under vehicle programs	2,770	2,537	966
Property and equipment, net	$ 163	$ 128	$ 43