Guarantor And Non-Guarantor Consolidating Condensed Financial Statements (Consolidating Condensed Statements Of Cash Flows) (Detail) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Supplemental Guarantor Financial Information [Line Items]
Net cash provided by (used in) operating activities	$ 1,027	$ 1,011
Property and equipment additions	(80)	(80)
Proceeds received on asset sales	6	6
Payments to Acquire Restricted Investments	(222)	(125)
Other, net	(1)	(8)
Net cash used in investing activities exclusive of vehicle programs	(297)	(207)
Decrease (increase) in program cash	(30)	(29)
Investment in vehicles	(7,939)	(8,214)
Proceeds received on disposition of vehicles	4,549	4,382
Net cash used in investing activities of vehicle programs	(3,420)	(3,861)
Net cash used in investing activities	(3,717)	(4,068)
Proceeds from long-term borrowings	376	695
Principal payments on borrowings	(281)	(747)
Net change in short-term borrowings	(13)	0
Repurchases of common stock	(114)	(146)
Debt financing fees	(7)	(11)
Other, net	0	(1)
Net cash used in financing activities exclusive of vehicle programs	(39)	(210)
Proceeds from borrowings	9,018	9,536
Principal payments on borrowings	(6,347)	(6,417)
Debt financing fees	(17)	(10)
Net cash provided by financing activities of vehicle programs	2,654	3,109
Net cash provided by financing activities	2,615	2,899
Effect of changes in exchange rates on cash and cash equivalents	(20)	2
Net decrease in cash and cash equivalents	(95)	(156)
Cash and cash equivalents, beginning of period	624	693
Cash and cash equivalents, end of period	529	537
Parent [Member]
Supplemental Guarantor Financial Information [Line Items]
Net cash provided by (used in) operating activities	3	2
Property and equipment additions	0	0
Proceeds received on asset sales	0	0
Payments to Acquire Restricted Investments	0	0
Other, net	114	136
Net cash used in investing activities exclusive of vehicle programs	114	136
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	114	136
Proceeds from long-term borrowings	0	0
Principal payments on borrowings	0	0
Net change in short-term borrowings	0
Repurchases of common stock	(114)	(146)
Debt financing fees	0	0
Other, net	0	(1)
Net cash used in financing activities exclusive of vehicle programs	(114)	(147)
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	(114)	(147)
Effect of changes in exchange rates on cash and cash equivalents	0	0
Net decrease in cash and cash equivalents	3	(9)
Cash and cash equivalents, beginning of period	2	14
Cash and cash equivalents, end of period	5	5
Subsidiary Issuers [Member]
Supplemental Guarantor Financial Information [Line Items]
Net cash provided by (used in) operating activities	158	502
Property and equipment additions	(11)	(7)
Proceeds received on asset sales	3	2
Payments to Acquire Restricted Investments	(8)	0
Intercompany loan advances	(30)
Other, net	(95)	(7)
Net cash used in investing activities exclusive of vehicle programs	(141)	(12)
Decrease (increase) in program cash	0	0
Investment in vehicles	(1)	(3)
Proceeds received on disposition of vehicles	9	5
Net cash used in investing activities of vehicle programs	8	2
Net cash used in investing activities	(133)	(10)
Proceeds from long-term borrowings	375	400
Principal payments on borrowings	(250)	(744)
Net change in short-term borrowings	0
Repurchases of common stock	0	0
Debt financing fees	(7)	(6)
Other, net	(114)	(136)
Net cash used in financing activities exclusive of vehicle programs	4	(486)
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	4	(486)
Effect of changes in exchange rates on cash and cash equivalents	0	0
Net decrease in cash and cash equivalents	29	6
Cash and cash equivalents, beginning of period	210	242
Cash and cash equivalents, end of period	239	248
Guarantor Subsidiaries [Member]
Supplemental Guarantor Financial Information [Line Items]
Net cash provided by (used in) operating activities	69	45
Property and equipment additions	(38)	(39)
Proceeds received on asset sales	0	0
Payments to Acquire Restricted Investments	0	0
Intercompany loan advances	(94)
Other, net	1	(1)
Net cash used in investing activities exclusive of vehicle programs	(131)	(40)
Decrease (increase) in program cash	0	0
Investment in vehicles	(2)	(86)
Proceeds received on disposition of vehicles	0	0
Net cash used in investing activities of vehicle programs	(2)	(86)
Net cash used in investing activities	(133)	(126)
Proceeds from long-term borrowings	0	0
Principal payments on borrowings	(2)	(3)
Net change in short-term borrowings	0
Repurchases of common stock	0	0
Debt financing fees	0	0
Other, net	70	0
Net cash used in financing activities exclusive of vehicle programs	68	(3)
Proceeds from borrowings	0	73
Principal payments on borrowings	(4)	0
Debt financing fees	0	(1)
Net cash provided by financing activities of vehicle programs	(4)	72
Net cash provided by financing activities	64	69
Effect of changes in exchange rates on cash and cash equivalents	0	0
Net decrease in cash and cash equivalents	0	(12)
Cash and cash equivalents, beginning of period	0	12
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	797	462
Property and equipment additions	(31)	(34)
Proceeds received on asset sales	3	4
Payments to Acquire Restricted Investments	(214)	(125)
Other, net	0	0
Net cash used in investing activities exclusive of vehicle programs	(242)	(155)
Decrease (increase) in program cash	(30)	(29)
Investment in vehicles	(7,936)	(8,125)
Proceeds received on disposition of vehicles	4,540	4,377
Net cash used in investing activities of vehicle programs	(3,426)	(3,777)
Net cash used in investing activities	(3,668)	(3,932)
Proceeds from long-term borrowings	1	295
Principal payments on borrowings	(29)	0
Net change in short-term borrowings	(13)
Intercompany loan borrowings	124
Repurchases of common stock	0	0
Debt financing fees	0	(5)
Other, net	23	0
Net cash used in financing activities exclusive of vehicle programs	106	290
Proceeds from borrowings	9,018	9,463
Principal payments on borrowings	(6,343)	(6,417)
Debt financing fees	(17)	(9)
Net cash provided by financing activities of vehicle programs	2,658	3,037
Net cash provided by financing activities	2,764	3,327
Effect of changes in exchange rates on cash and cash equivalents	(20)	2
Net decrease in cash and cash equivalents	(127)	(141)
Cash and cash equivalents, beginning of period	412	425
Cash and cash equivalents, end of period	285	284
Eliminations [Member]
Supplemental Guarantor Financial Information [Line Items]
Net cash provided by (used in) operating activities	0	0
Property and equipment additions	0	0
Proceeds received on asset sales	0	0
Payments to Acquire Restricted Investments	0	0
Intercompany loan advances	124
Other, net	(21)	(136)
Net cash used in investing activities exclusive of vehicle programs	103	(136)
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	103	(136)
Proceeds from long-term borrowings	0	0
Principal payments on borrowings	0	0
Net change in short-term borrowings	0
Intercompany loan borrowings	(124)
Repurchases of common stock	0	0
Debt financing fees	0	0
Other, net	21	136
Net cash used in financing activities exclusive of vehicle programs	(103)	136
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	(103)	136
Effect of changes in exchange rates on cash and cash equivalents	0	0
Net decrease 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