Guarantor And Non-Guarantor Consolidating Condensed Financial Statements (Consolidating Condensed Statements Of Comprehensive Income) (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Revenues
Revenues	$ 2,337	$ 2,328	$ 4,257	$ 4,296
Expenses
Operating	1,172	1,175	2,243	2,267
Vehicle depreciation and lease charges, net	543	591	1,028	1,106
Selling, general and administrative	313	321	597	617
Vehicle interest, net	90	80	171	152
Non-vehicle related depreciation and amortization	66	67	133	128
Interest expense	48	49	90	95
Intercompany interest expense (income)	0	0	0	0
Early extinguishment of debt	0	0	0	5
Restructuring and other related charges	23	4	44	10
Transaction-related costs, net	1	3	6	7
Total expenses	2,256	2,290	4,312	4,387
Income (loss) before income taxes and equity in earnings of subsidiaries	81	38	(55)	(91)
Provision for (benefit from) income taxes	(19)	(12)	26	30
Equity in earnings of subsidiaries	0	0	0	0
Net income	62	26	(29)	(61)
Comprehensive income	60	(24)	(36)	(103)
Eliminations [Member]
Revenues
Revenues	(646)	(657)	(1,218)	(1,232)
Expenses
Operating	0	0	0	0
Vehicle depreciation and lease charges, net	(575)	(596)	(1,083)	(1,121)
Selling, general and administrative	0	0	0	0
Vehicle interest, net	(71)	(61)	(135)	(111)
Non-vehicle related depreciation and amortization	0	0	0	0
Interest expense	0	0	0	0
Intercompany interest expense (income)	0	0	0	0
Restructuring and other related charges	0	0	0	0
Transaction-related costs, net	0	0	0	0
Total expenses	(646)	(657)	(1,218)	(1,232)
Income (loss) before income taxes and equity in earnings of subsidiaries	0	0	0	0
Provision for (benefit from) income taxes	0	0	0	0
Equity in earnings of subsidiaries	(505)	(283)	(507)	(367)
Net income	(505)	(283)	(507)	(367)
Comprehensive income	(522)	(128)	(523)	(222)
Parent Company [Member]
Revenues
Revenues	0	0	0	0
Expenses
Operating	1	1	1	2
Vehicle depreciation and lease charges, net	0	0	0	0
Selling, general and administrative	10	10	21	28
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)	(6)	(6)
Restructuring and other related charges	8	0	11	0
Transaction-related costs, net	0	0	0	0
Total expenses	16	8	27	24
Income (loss) before income taxes and equity in earnings of subsidiaries	(16)	(8)	(27)	(24)
Provision for (benefit from) income taxes	6	5	10	11
Equity in earnings of subsidiaries	72	29	(12)	(48)
Net income	62	26	(29)	(61)
Comprehensive income	60	(24)	(36)	(103)
Subsidiaries [Member]
Revenues
Revenues	0	0	0	0
Expenses
Operating	0	(3)	0	1
Vehicle depreciation and lease charges, net	0	0	0	0
Selling, general and administrative	6	3	8	6
Vehicle interest, net	0	0	0	0
Non-vehicle related depreciation and amortization	5	1	5	1
Interest expense	34	39	68	78
Intercompany interest expense (income)	22	(31)	8	(9)
Early extinguishment of debt				5
Restructuring and other related charges	0	0	0	0
Transaction-related costs, net	1	1	1	1
Total expenses	68	10	90	83
Income (loss) before income taxes and equity in earnings of subsidiaries	(68)	(10)	(90)	(83)
Provision for (benefit from) income taxes	24	3	32	22
Equity in earnings of subsidiaries	116	36	46	13
Net income	72	29	(12)	(48)
Comprehensive income	70	(21)	(19)	(90)
Guarantor Subsidiaries [Member]
Revenues
Revenues	1,442	1,395	2,630	2,579
Expenses
Operating	720	677	1,334	1,298
Vehicle depreciation and lease charges, net	597	605	1,126	1,141
Selling, general and administrative	168	176	331	331
Vehicle interest, net	72	61	135	113
Non-vehicle related depreciation and amortization	35	36	73	72
Interest expense	1	1	1	2
Intercompany interest expense (income)	7	5	14	11
Restructuring and other related charges	11	1	25	4
Transaction-related costs, net	(7)	1	(6)	1
Total expenses	1,604	1,563	3,033	2,973
Income (loss) before income taxes and equity in earnings of subsidiaries	(162)	(168)	(403)	(394)
Provision for (benefit from) income taxes	(39)	(14)	(24)	5
Equity in earnings of subsidiaries	317	218	473	402
Net income	116	36	46	13
Comprehensive income	126	(16)	58	(37)
Non-Guarantor Subsidiaries [Member]
Revenues
Revenues	1,541	1,590	2,845	2,949
Expenses
Operating	451	500	908	966
Vehicle depreciation and lease charges, net	521	582	985	1,086
Selling, general and administrative	129	132	237	252
Vehicle interest, net	89	80	171	150
Non-vehicle related depreciation and amortization	26	30	55	55
Interest expense	13	9	21	15
Intercompany interest expense (income)	(26)	29	(16)	4
Restructuring and other related charges	4	3	8	6
Transaction-related costs, net	7	1	11	5
Total expenses	1,214	1,366	2,380	2,539
Income (loss) before income taxes and equity in earnings of subsidiaries	327	224	465	410
Provision for (benefit from) income taxes	(10)	(6)	8	(8)
Equity in earnings of subsidiaries	0	0	0	0
Net income	317	218	473	402
Comprehensive income	$ 326	$ 165	$ 484	$ 349