Guarantor And Non-Guarantor Consolidating Condensed Financial Statements (Consolidating Condensed Statements Of Cash Flows) (Detail) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Supplemental Guarantor Financial Information [Line Items]
Net cash provided by (used in) operating activities	$ 1,070	$ 1,027
Property and equipment additions	(89)	(80)
Proceeds received on asset sales	7	6
Payments to Acquire Restricted Investments	(3)	(222)
Other, net	4	(1)
Net cash used in investing activities exclusive of vehicle programs	(81)	(297)
Decrease (increase) in program cash	82	(30)
Investment in vehicles	(8,500)	(7,939)
Proceeds received on disposition of vehicles	5,418	4,549
Net cash used in investing activities of vehicle programs	(3,000)	(3,420)
Net cash used in investing activities	(3,081)	(3,717)
Proceeds from long-term borrowings	558	376
Principal payments on borrowings	(520)	(281)
Net change in short-term borrowings	0	(13)
Intercompany loan borrowings	0	0
Proceeds from (Repayments of) Related Party Debt	0	0
Repurchases of common stock	(174)	(114)
Debt financing fees	(10)	(7)
Other, net	0	0
Net cash provided by financing activities exclusive of vehicle programs	(146)	(39)
Proceeds from borrowings	9,850	9,018
Principal payments on borrowings	(7,614)	(6,347)
Debt financing fees	(17)	(17)
Net cash provided by financing activities of vehicle programs	2,219	2,654
Net cash provided by financing activities	2,073	2,615
Effect of changes in exchange rates on cash and cash equivalents	13	(20)
Net increase in cash and cash equivalents	75	(95)
Cash and cash equivalents, beginning of period	452	624
Cash and cash equivalents, end of period	527	529
Parent [Member]
Supplemental Guarantor Financial Information [Line Items]
Net cash provided by (used in) operating activities	80	3
Property and equipment additions	0	0
Proceeds received on asset sales	0	0
Payments to Acquire Restricted Investments	0	0
Other, net	93	114
Net cash used in investing activities exclusive of vehicle programs	93	114
Decrease (increase) in program cash	0	0
Investment in vehicles	0	0
Proceeds received on disposition of vehicles	0	0
Net cash used in investing activities of vehicle programs	0	0
Net cash used in investing activities	93	114
Proceeds from long-term borrowings	0	0
Principal payments on borrowings	0	0
Net change in short-term borrowings		0
Intercompany loan borrowings	0	0
Proceeds from (Repayments of) Related Party Debt	0	0
Repurchases of common stock	(174)	(114)
Debt financing fees	0	0
Other, net	0	0
Net cash provided by financing activities exclusive of vehicle programs	(174)	(114)
Proceeds from borrowings	0	0
Principal payments on borrowings	0	0
Debt financing fees	0	0
Net cash provided by financing activities of vehicle programs	0	0
Net cash provided by financing activities	(174)	(114)
Effect of changes in exchange rates on cash and cash equivalents	0	0
Net increase in cash and cash equivalents	(1)	3
Cash and cash equivalents, beginning of period	4	2
Cash and cash equivalents, end of period	3	5
Subsidiary Issuers [Member]
Supplemental Guarantor Financial Information [Line Items]
Net cash provided by (used in) operating activities	144	158
Property and equipment additions	(11)	(11)
Proceeds received on asset sales	4	3
Payments to Acquire Restricted Investments	0	(8)
Other, net	0	(95)
Net cash used in investing activities exclusive of vehicle programs	(7)	(141)
Decrease (increase) in program cash	0	0
Investment in vehicles	(2)	(1)
Proceeds received on disposition of vehicles	20	9
Net cash used in investing activities of vehicle programs	18	8
Net cash used in investing activities	11	(133)
Proceeds from long-term borrowings	557	375
Principal payments on borrowings	(518)	(250)
Net change in short-term borrowings		0
Intercompany loan borrowings	0	0
Proceeds from (Repayments of) Related Party Debt	0	(30)
Repurchases of common stock	0	0
Debt financing fees	(10)	(7)
Other, net	(173)	(114)
Net cash provided by financing activities exclusive of vehicle programs	(144)	4
Proceeds from borrowings	0	0
Principal payments on borrowings	0	0
Debt financing fees	0	0
Net cash provided by financing activities of vehicle programs	0	0
Net cash provided by financing activities	(144)	4
Effect of changes in exchange rates on cash and cash equivalents	0	0
Net increase in cash and cash equivalents	11	29
Cash and cash equivalents, beginning of period	70	210
Cash and cash equivalents, end of period	81	239
Guarantor Subsidiaries [Member]
Supplemental Guarantor Financial Information [Line Items]
Net cash provided by (used in) operating activities	30	69
Property and equipment additions	(46)	(38)
Proceeds received on asset sales	1	0
Payments to Acquire Restricted Investments	(1)	0
Other, net	0	1
Net cash used in investing activities exclusive of vehicle programs	(18)	(131)
Decrease (increase) in program cash	0	0
Investment in vehicles	(7)	(2)
Proceeds received on disposition of vehicles	0	0
Net cash used in investing activities of vehicle programs	(7)	(2)
Net cash used in investing activities	(25)	(133)
Proceeds from long-term borrowings	0	0
Principal payments on borrowings	(1)	(2)
Net change in short-term borrowings		0
Intercompany loan borrowings	0	0
Proceeds from (Repayments of) Related Party Debt	28	(94)
Repurchases of common stock	0	0
Debt financing fees	0	0
Other, net	0	70
Net cash provided by financing activities exclusive of vehicle programs	(1)	68
Proceeds from borrowings	0	0
Principal payments on borrowings	(4)	(4)
Debt financing fees	0	0
Net cash provided by financing activities of vehicle programs	(4)	(4)
Net cash provided by financing activities	(5)	64
Effect of changes in exchange rates on cash and cash equivalents	0	0
Net increase in cash and cash equivalents	0	0
Cash and cash equivalents, beginning of period	0	0
Cash and cash equivalents, end of period	0	0
Non-Guarantor Subsidiaries [Member]
Supplemental Guarantor Financial Information [Line Items]
Net cash provided by (used in) operating activities	896	797
Property and equipment additions	(32)	(31)
Proceeds received on asset sales	2	3
Payments to Acquire Restricted Investments	(2)	(214)
Other, net	4	0
Net cash used in investing activities exclusive of vehicle programs	(28)	(242)
Decrease (increase) in program cash	82	(30)
Investment in vehicles	(8,491)	(7,936)
Proceeds received on disposition of vehicles	5,398	4,540
Net cash used in investing activities of vehicle programs	(3,011)	(3,426)
Net cash used in investing activities	(3,039)	(3,668)
Proceeds from long-term borrowings	1	1
Principal payments on borrowings	(1)	(29)
Net change in short-term borrowings		(13)
Intercompany loan borrowings	(28)	124
Proceeds from (Repayments of) Related Party Debt	0	0
Repurchases of common stock	0	0
Debt financing fees	0	0
Other, net	0	23
Net cash provided by financing activities exclusive of vehicle programs	(28)	106
Proceeds from borrowings	9,850	9,018
Principal payments on borrowings	(7,610)	(6,343)
Debt financing fees	(17)	(17)
Net cash provided by financing activities of vehicle programs	2,223	2,658
Net cash provided by financing activities	2,195	2,764
Effect of changes in exchange rates on cash and cash equivalents	13	(20)
Net increase in cash and cash equivalents	65	(127)
Cash and cash equivalents, beginning of period	378	412
Cash and cash equivalents, end of period	443	285
Eliminations [Member]
Supplemental Guarantor Financial Information [Line Items]
Net cash provided by (used in) operating activities	(80)	0
Property and equipment additions	0	0
Proceeds received on asset sales	0	0
Payments to Acquire Restricted Investments	0	0
Other, net	(93)	(21)
Net cash used in investing activities exclusive of vehicle programs	(121)	103
Decrease (increase) in program cash	0	0
Investment in vehicles	0	0
Proceeds received on disposition of vehicles	0	0
Net cash used in investing activities of vehicle programs	0	0
Net cash used in investing activities	(121)	103
Proceeds from long-term borrowings	0	0
Principal payments on borrowings	0	0
Net change in short-term borrowings		0
Intercompany loan borrowings	28	(124)
Proceeds from (Repayments of) Related Party Debt	(28)	124
Repurchases of common stock	0	0
Debt financing fees	0	0
Other, net	173	21
Net cash provided by financing activities exclusive of vehicle programs	201	(103)
Proceeds from borrowings	0	0
Principal payments on borrowings	0	0
Debt financing fees		0
Net cash provided by financing activities of vehicle programs	0	0
Net cash provided by financing activities	201	(103)
Effect of changes in exchange rates on cash and cash equivalents	0	0
Net increase in cash and cash equivalents	0	0
Cash and cash equivalents, beginning of period	0	0
Cash and cash equivalents, end of period	$ 0	$ 0