Guarantor And Non-Guarantor Consolidating Condensed Financial Statements (Consolidating Condensed Statements Of Cash Flows) (Detail) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Supplemental Guarantor Financial Information [Line Items]
Net cash provided by (used in) operating activities	$ 1,011	$ 874
Property and equipment additions	(80)	(56)
Proceeds received on asset sales	6	7
Payments to Acquire Restricted Investments	(125)	(476)
Proceeds from (Repayments of) Related Party Debt		0
Other, net	(8)	50
Net cash used in investing activities exclusive of vehicle programs	(207)	(475)
Decrease (increase) in program cash	(29)	(111)
Investment in vehicles	(8,214)	(7,306)
Proceeds received on disposition of vehicles	4,382	4,434
Net cash used in investing activities of vehicle programs	(3,861)	(2,983)
Net cash used in investing activities	(4,068)	(3,458)
Proceeds from long-term borrowings	695	2,725
Principal payments on borrowings	(747)	(2,338)
Net change in short-term borrowings	0	10
Purchase of warrants	0	(29)
Proceeds from sale of call options	0	40
Repurchases of common stock	(146)
Net intercompany transactions		0
Debt financing fees	(11)	(28)
Other, net	(1)	2
Net cash provided by (used in) financing activities exclusive of vehicle programs	(210)	382
Proceeds from borrowings	9,536	8,191
Principal payments on borrowings	(6,417)	(6,055)
Debt financing fees	(10)	(20)
Net cash provided by financing activities of vehicle programs	3,109	2,116
Net cash provided by financing activities	2,899	2,498
Effect of changes in exchange rates on cash and cash equivalents	2	(17)
Net decrease in cash and cash equivalents	(156)	(103)
Cash and cash equivalents, beginning of period	693	606
Cash and cash equivalents, end of period	537	503
Parent [Member]
Supplemental Guarantor Financial Information [Line Items]
Net cash provided by (used in) operating activities	2	(5)
Property and equipment additions	0	0
Proceeds received on asset sales	0	0
Payments to Acquire Restricted Investments	0	0
Proceeds from (Repayments of) Related Party Debt		0
Other, net	136	87
Net cash used in investing activities exclusive of vehicle programs	136	87
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	136	87
Proceeds from long-term borrowings	0	0
Principal payments on borrowings	0	(93)
Net change in short-term borrowings		0
Purchase of warrants		(29)
Proceeds from sale of call options		40
Repurchases of common stock	(146)
Net intercompany transactions		0
Debt financing fees	0	0
Other, net	(1)	2
Net cash provided by (used in) financing activities exclusive of vehicle programs	(147)	(80)
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	(147)	(80)
Effect of changes in exchange rates on cash and cash equivalents	0	0
Net decrease in cash and cash equivalents	(9)	2
Cash and cash equivalents, beginning of period	14	5
Cash and cash equivalents, end of period	5	7
Subsidiary Issuers [Member]
Supplemental Guarantor Financial Information [Line Items]
Net cash provided by (used in) operating activities	502	48
Property and equipment additions	(7)	(11)
Proceeds received on asset sales	2	3
Payments to Acquire Restricted Investments	0	(513)
Proceeds from (Repayments of) Related Party Debt		70
Other, net	(7)	(1)
Net cash used in investing activities exclusive of vehicle programs	(12)	(452)
Decrease (increase) in program cash	0	0
Investment in vehicles	(3)	(3)
Proceeds received on disposition of vehicles	5	2
Net cash used in investing activities of vehicle programs	2	(1)
Net cash used in investing activities	(10)	(453)
Proceeds from long-term borrowings	400	2,725
Principal payments on borrowings	(744)	(2,243)
Net change in short-term borrowings		0
Purchase of warrants		0
Proceeds from sale of call options		0
Repurchases of common stock	0
Net intercompany transactions		0
Debt financing fees	(6)	(28)
Other, net	(136)	(87)
Net cash provided by (used in) financing activities exclusive of vehicle programs	(486)	367
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	(486)	367
Effect of changes in exchange rates on cash and cash equivalents	0	0
Net decrease in cash and cash equivalents	6	(38)
Cash and cash equivalents, beginning of period	242	102
Cash and cash equivalents, end of period	248	64
Guarantor Subsidiaries [Member]
Supplemental Guarantor Financial Information [Line Items]
Net cash provided by (used in) operating activities	45	(32)
Property and equipment additions	(39)	(24)
Proceeds received on asset sales	0	0
Payments to Acquire Restricted Investments	0	16
Proceeds from (Repayments of) Related Party Debt		0
Other, net	(1)	43
Net cash used in investing activities exclusive of vehicle programs	(40)	35
Decrease (increase) in program cash	0	0
Investment in vehicles	(86)	(1)
Proceeds received on disposition of vehicles	0	0
Net cash used in investing activities of vehicle programs	(86)	(1)
Net cash used in investing activities	(126)	34
Proceeds from long-term borrowings	0	0
Principal payments on borrowings	(3)	(2)
Net change in short-term borrowings		0
Purchase of warrants		0
Proceeds from sale of call options		0
Repurchases of common stock	0
Net intercompany transactions		0
Debt financing fees	0	0
Other, net	0	0
Net cash provided by (used in) financing activities exclusive of vehicle programs	(3)	(2)
Proceeds from borrowings	73	0
Principal payments on borrowings	0	0
Debt financing fees	(1)	0
Net cash provided by financing activities of vehicle programs	72	0
Net cash provided by financing activities	69	(2)
Effect of changes in exchange rates on cash and cash equivalents	0	0
Net decrease in cash and cash equivalents	(12)	0
Cash and cash equivalents, beginning of period	12	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	462	866
Property and equipment additions	(34)	(21)
Proceeds received on asset sales	4	4
Payments to Acquire Restricted Investments	(125)	21
Proceeds from (Repayments of) Related Party Debt		0
Other, net	0	8
Net cash used in investing activities exclusive of vehicle programs	(155)	12
Decrease (increase) in program cash	(29)	(111)
Investment in vehicles	(8,125)	(7,302)
Proceeds received on disposition of vehicles	4,377	4,432
Net cash used in investing activities of vehicle programs	(3,777)	(2,981)
Net cash used in investing activities	(3,932)	(2,969)
Proceeds from long-term borrowings	295	0
Principal payments on borrowings	0	0
Net change in short-term borrowings		10
Purchase of warrants		0
Proceeds from sale of call options		0
Repurchases of common stock	0
Net intercompany transactions		(70)
Debt financing fees	(5)	0
Other, net	0	(3)
Net cash provided by (used in) financing activities exclusive of vehicle programs	290	(63)
Proceeds from borrowings	9,463	8,191
Principal payments on borrowings	(6,417)	(6,055)
Debt financing fees	(9)	(20)
Net cash provided by financing activities of vehicle programs	3,037	2,116
Net cash provided by financing activities	3,327	2,053
Effect of changes in exchange rates on cash and cash equivalents	2	(17)
Net decrease in cash and cash equivalents	(141)	(67)
Cash and cash equivalents, beginning of period	425	499
Cash and cash equivalents, end of period	284	432
Eliminations [Member]
Supplemental Guarantor Financial Information [Line Items]
Net cash provided by (used in) operating activities	0	(3)
Property and equipment additions	0	0
Proceeds received on asset sales	0	0
Payments to Acquire Restricted Investments	0	0
Proceeds from (Repayments of) Related Party Debt		(70)
Other, net	(136)	(87)
Net cash used in investing activities exclusive of vehicle programs	(136)	(157)
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	(136)	(157)
Proceeds from long-term borrowings	0	0
Principal payments on borrowings	0	0
Net change in short-term borrowings		0
Purchase of warrants		0
Proceeds from sale of call options		0
Repurchases of common stock	0
Net intercompany transactions		70
Debt financing fees	0	0
Other, net	136	90
Net cash provided by (used in) financing activities exclusive of vehicle programs	136	160
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	136	160
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