Segment Information (Narrative) (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Segment Reporting Information [Line Items]
Document Period End Date			Sep. 30, 2016
Revenues	$ 2,656	$ 2,577	$ 6,780	$ 6,600
Adjusted EBITDA	469	431	717	775
Non Vehicle Related Depreciation And Amortization	63	56	189	161
Restructuring expense	6	6	26	10
Income before income taxes	345	312	322	378
Assets Under Vehicle Programs	12,797		12,797		$ 11,716
International
Segment Reporting Information [Line Items]
Revenues	835	801	2,002	1,893
Adjusted EBITDA	179	168	237	245
Assets Under Vehicle Programs	2,900		2,900		2,300
Americas
Segment Reporting Information [Line Items]
Revenues	1,821	1,776	4,778	4,707
Adjusted EBITDA	306	279	532	572
Assets Under Vehicle Programs	2,300		2,300		$ 1,900
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Revenues	0	0	0	0
Adjusted EBITDA	$ (16)	$ (16)	$ (52)	$ (42)