Segment Information (Narrative) (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	Dec. 31, 2013
Segment Reporting Information [Line Items]
Segment Reporting, Change in Measurement Method		$ 13		$ 28
Sales Revenue, Services, Net	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
Assets under vehicle programs	12,565		12,565		10,452
Non current deferred tax assets	1,042		1,042		1,299
Loss before income taxes	306	230	359	135
North America
Segment Reporting Information [Line Items]
Segment Reporting, Change in Measurement Method		3		6
Sales Revenue, Services, Net	1,623	1,500	4,286	3,877
Adjusted EBITDA	255	226	526	434
Restructuring expense			3
Assets under vehicle programs	9,600		9,600		7,900
International
Segment Reporting Information [Line Items]
Segment Reporting, Change in Measurement Method		5		14
Sales Revenue, Services, Net	815	786	2,033	1,923
Adjusted EBITDA	160	149	234	224
Restructuring expense			13
Assets under vehicle programs	2,600		2,600		2,200
Truck Rental [Member]
Segment Reporting Information [Line Items]
Segment Reporting, Change in Measurement Method		6		19
Sales Revenue, Services, Net	104	109	279	287
Adjusted EBITDA	18	19	29	31
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Sales Revenue, Services, Net	0	0	0	0
Adjusted EBITDA	$ (16)	$ (11)	$ (42)	$ (35)