Segment Information (Summary Of Segments Information) (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]
Assets Under Vehicle Programs	$ 12,797		$ 12,797		$ 11,716
Document Fiscal Year Focus			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
Interest expense	51	49	157	146
Early extinguishment of debt	0	0	10	23
Transaction-related costs, net	4	8	13	57
Restructuring expense	6	6	26	10
Income before income taxes	345	312	322	378
Americas
Segment Reporting Information [Line Items]
Assets Under Vehicle Programs	2,300		2,300		1,900
Revenues	1,821	1,776	4,778	4,707
Adjusted EBITDA	306	279	532	572
International
Segment Reporting Information [Line Items]
Assets Under Vehicle Programs	2,900		2,900		$ 2,300
Revenues	835	801	2,002	1,893
Adjusted EBITDA	179	168	237	245
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Revenues	0	0	0	0
Adjusted EBITDA	$ (16)	$ (16)	$ (52)	$ (42)