Summary of Geographic Segment Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	$ 8,659	$ 8,502	$ 8,485
Assets exclusive of assets under vehicle programs	6,065	5,918	5,784
Assets under vehicle programs	11,578	11,716	11,058
Long-Lived Assets	2,562	2,571	2,366
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	5,674	5,635	5,471
Assets exclusive of assets under vehicle programs	3,699	3,677	3,745
Assets under vehicle programs	8,552	8,786	8,428
Long-Lived Assets	1,489	1,502	1,481
All Other Countries
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	2,985	2,867	3,014
Assets exclusive of assets under vehicle programs	2,366	2,241	2,039
Assets under vehicle programs	3,026	2,930	2,630
Long-Lived Assets	$ 1,073	$ 1,069	$ 885