Segment Information (Summary Of Segments Information) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Segment Reporting Information [Line Items]
Segment Reporting, Change in Measurement Method		$ 13		$ 28
Revenues	2,542	2,395	6,598	6,087
Adjusted EBITDA	417	383	747	654
Non-vehicle related depreciation and amortization	46	39	132	109
Interest expense	50	57	161	170
Early extinguishment of debt	0	0	56	131
Transaction-related costs	7	10	23	37
Restructuring expense	8	14	16	39
Other than Temporary Impairment Losses, Investments	0	33	0	33
Income before income taxes	306	230	359	135
Segment Reporting, Change in Measurement Method - EBITDA				1
North America
Segment Reporting Information [Line Items]
Segment Reporting, Change in Measurement Method		3		6
Revenues	1,623	1,500	4,286	3,877
Adjusted EBITDA	255	226	526	434
Restructuring expense			3
International
Segment Reporting Information [Line Items]
Segment Reporting, Change in Measurement Method		5		14
Revenues	815	786	2,033	1,923
Adjusted EBITDA	160	149	234	224
Restructuring expense			13
Truck Rental [Member]
Segment Reporting Information [Line Items]
Segment Reporting, Change in Measurement Method		6		19
Revenues	104	109	279	287
Adjusted EBITDA	18	19	29	31
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Revenues	0	0	0	0
Adjusted EBITDA	$ (16)	$ (11)	$ (42)	$ (35)