Segment Information (Summary Of Segments Information) (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Segment Reporting Information [Line Items]
Segment Reporting, Change in Measurement Method		$ 15		$ 34
Revenues	$ 2,173	2,194	$ 4,023	4,056
Adjusted EBITDA	227	213	344	330
Non-vehicle related depreciation and amortization	56	45	105	86
Interest expense related to corporate debt, net:	45	55	97	111
Early Debt Extinguishment	23	56	23	56
Transaction-related costs	18	8	49	16
Restructuring expense	3	1	4	8
Income before income taxes	82	48	66	53
Americas
Segment Reporting Information [Line Items]
Revenues	1,556	1,542	2,931	2,872
Adjusted EBITDA	178	172	293	287
International
Segment Reporting Information [Line Items]
Segment Reporting, Change in Measurement Method		2		5
Revenues	617	652	1,092	1,184
Adjusted EBITDA	61	55	77	69
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Revenues	0	0	0	0
Adjusted EBITDA	$ (12)	$ (14)	$ (26)	$ (26)