Guarantor And Non-Guarantor Consolidating Condensed Financial Statements (Consolidating Condensed Statements Of Comprehensive Income) (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Revenues
Vehicle rental	$ 1,949	$ 1,871	$ 4,798	$ 4,772
Other	803	785	2,031	2,008
Net revenues	2,752	2,656	6,829	6,780
Expenses
Operating	1,256	1,219	3,413	3,381
Vehicle depreciation and lease charges, net	616	576	1,717	1,571
Selling, general and administrative	320	315	875	896
Vehicle interest, net	78	77	215	215
Non-vehicle related depreciation and amortization	66	63	194	189
Interest expense	45	51	142	157
Intercompany interest expense (income)	0	0	0	0
Early extinguishment of debt			3	10
Restructuring and other related charges	7	6	52	26
Transaction-related costs, net	0	4	8	13
Total expenses	2,388	2,311	6,619	6,458
Income before income taxes	364	345	210	322
Provision for (benefit from) income taxes	(119)	(136)	(69)	(128)
Equity in earnings (loss) of subsidiaries	0	0	0	0
Net income (loss)	245	209	141	194
Comprehensive income (loss)	(279)	(235)	(251)	(294)
Eliminations [Member]
Revenues
Vehicle rental	0	0	0	0
Other	(611)	(580)	(1,859)	(1,669)
Net revenues	(611)	(580)	(1,859)	(1,669)
Expenses
Operating	0	0	0	0
Vehicle depreciation and lease charges, net	(557)	(524)	(1,701)	(1,514)
Selling, general and administrative	0	0	0	0
Vehicle interest, net	(54)	(56)	(158)	(155)
Non-vehicle related depreciation and amortization	0	0	0	0
Interest expense	0	0	0	0
Intercompany interest expense (income)	0	0	0	0
Early extinguishment of debt			0	0
Restructuring and other related charges	0	0	0	0
Transaction-related costs, net		0	0	0
Total expenses	(611)	(580)	(1,859)	(1,669)
Income before income taxes	0	0	0	0
Provision for (benefit from) income taxes	0	0	0	0
Equity in earnings (loss) of subsidiaries	(895)	(741)	(1,244)	(1,081)
Net income (loss)	(895)	(741)	(1,244)	(1,081)
Comprehensive income (loss)	993	808	1,571	1,382
Parent Company [Member]
Revenues
Vehicle rental	0	0	0	0
Other	0	0	0	0
Net revenues	0	0	0	0
Expenses
Operating	0	1	2	3
Vehicle depreciation and lease charges, net	0	0	0	0
Selling, general and administrative	9	10	29	29
Vehicle interest, net	0	0	0	0
Non-vehicle related depreciation and amortization	0	0	0	0
Interest expense	0	0	0	0
Intercompany interest expense (income)	(3)	(3)	(9)	(9)
Early extinguishment of debt			0	0
Restructuring and other related charges	0	0	0	0
Transaction-related costs, net		0	0	0
Total expenses	6	8	22	23
Income before income taxes	(6)	(8)	(22)	(23)
Provision for (benefit from) income taxes	6	3	10	9
Equity in earnings (loss) of subsidiaries	245	214	153	208
Net income (loss)	245	209	141	194
Comprehensive income (loss)	(279)	(235)	(251)	(294)
Subsidiaries [Member]
Revenues
Vehicle rental	0	0	0	0
Other	0	0	0	0
Net revenues	0	0	0	0
Expenses
Operating	5	3	18	14
Vehicle depreciation and lease charges, net	0	0	0	0
Selling, general and administrative	2	4	6	14
Vehicle interest, net	0	0	0	0
Non-vehicle related depreciation and amortization	0	0	1	1
Interest expense	38	41	118	122
Intercompany interest expense (income)	25	(3)	80	(8)
Early extinguishment of debt			4	10
Restructuring and other related charges	5	0	7	0
Transaction-related costs, net		0	0	1
Total expenses	75	45	234	154
Income before income taxes	(75)	(45)	(234)	(154)
Provision for (benefit from) income taxes	30	18	92	61
Equity in earnings (loss) of subsidiaries	290	241	295	301
Net income (loss)	245	214	153	208
Comprehensive income (loss)	(278)	(239)	(262)	(307)
Guarantor Subsidiaries [Member]
Revenues
Vehicle rental	1,228	1,216	3,169	3,229
Other	341	344	924	931
Net revenues	1,569	1,560	4,093	4,160
Expenses
Operating	710	719	1,994	2,013
Vehicle depreciation and lease charges, net	568	525	1,728	1,514
Selling, general and administrative	174	173	485	492
Vehicle interest, net	53	55	150	149
Non-vehicle related depreciation and amortization	41	38	121	115
Interest expense	2	1	3	3
Intercompany interest expense (income)	6	6	17	17
Early extinguishment of debt			0	0
Restructuring and other related charges	(2)	1	37	8
Transaction-related costs, net		0	0	1
Total expenses	1,552	1,518	4,535	4,312
Income before income taxes	17	42	(442)	(152)
Provision for (benefit from) income taxes	(87)	(87)	(59)	(119)
Equity in earnings (loss) of subsidiaries	360	286	796	572
Net income (loss)	290	241	295	301
Comprehensive income (loss)	(323)	(262)	(405)	(403)
Non-Guarantor Subsidiaries [Member]
Revenues
Vehicle rental	721	655	1,629	1,543
Other	1,073	1,021	2,966	2,746
Net revenues	1,794	1,676	4,595	4,289
Expenses
Operating	541	496	1,399	1,351
Vehicle depreciation and lease charges, net	605	575	1,690	1,571
Selling, general and administrative	135	128	355	361
Vehicle interest, net	79	78	223	221
Non-vehicle related depreciation and amortization	25	25	72	73
Interest expense	5	9	21	32
Intercompany interest expense (income)	(28)	0	(88)	0
Early extinguishment of debt			(1)	0
Restructuring and other related charges	4	5	8	18
Transaction-related costs, net		4	8	11
Total expenses	1,366	1,320	3,687	3,638
Income before income taxes	428	356	908	651
Provision for (benefit from) income taxes	(68)	(70)	(112)	(79)
Equity in earnings (loss) of subsidiaries	0	0	0	0
Net income (loss)	360	286	796	572
Comprehensive income (loss)	$ (392)	$ (307)	$ (904)	$ (672)