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, 2013	Jun. 30, 2012
Supplemental Guarantor Financial Information [Line Items]
Net cash provided by (used in) operating activities	$ 874	$ 722
Property and equipment additions	(56)	(49)
Proceeds received on asset sales	7	13
Payments to Acquire Restricted Investments	(476)	(5)
Other, net	50	(2)
Net cash used in investing activities exclusive of vehicle programs	(475)	(43)
Decrease (increase) in program cash	(111)	(61)
Investment in vehicles	(7,306)	(6,938)
Proceeds received on disposition of vehicles	4,434	4,077
Net cash used in investing activities of vehicle programs	(2,983)	(2,922)
Net cash used in investing activities	(3,458)	(2,965)
Proceeds from long-term borrowings	2,725	654
Principal payments on borrowings	(2,338)	(853)
Net change in short-term borrowings	10	(1)
Purchase of warrants	(29)	(26)
Proceeds from sale of call options	40	38
Net intercompany transactions	0	0
Debt financing fees	(28)	(9)
Other, net	2	0
Net cash provided by financing activities exclusive of vehicle programs	382	(197)
Proceeds from borrowings	8,191	7,172
Principal payments on borrowings	(6,055)	(4,802)
Debt financing fees	(20)	(11)
Net cash provided by financing activities of vehicle programs	2,116	2,359
Net cash provided by financing activities	2,498	2,162
Effect of changes in exchange rates on cash and cash equivalents	(17)	1
Net increase (decrease) in cash and cash equivalents	(103)	(80)
Cash and cash equivalents, beginning of period	606	534
Cash and cash equivalents, end of period	503	454
Parent [Member]
Supplemental Guarantor Financial Information [Line Items]
Net cash provided by (used in) operating activities	(2)	(45)
Property and equipment additions	0	0
Proceeds received on asset sales	0	0
Other, net	0	4
Net cash used in investing activities exclusive of vehicle programs	0	4
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	0	4
Proceeds from long-term borrowings	0	0
Principal payments on borrowings	(93)	(201)
Net change in short-term borrowings	0	0
Purchase of warrants	(29)	(26)
Proceeds from sale of call options	40	38
Net intercompany transactions	84	231
Debt financing fees	0	0
Other, net	2
Net cash provided by financing activities exclusive of vehicle programs	4	42
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	42
Effect of changes in exchange rates on cash and cash equivalents	0	0
Net increase (decrease) in cash and cash equivalents	2	1
Cash and cash equivalents, beginning of period	5	2
Cash and cash equivalents, end of period	7	3
Subsidiary Issuers [Member]
Supplemental Guarantor Financial Information [Line Items]
Net cash provided by (used in) operating activities	45	52
Property and equipment additions	(11)	(13)
Proceeds received on asset sales	3	4
Payments to Acquire Restricted Investments	(513)	0
Other, net	(1)	(2)
Net cash used in investing activities exclusive of vehicle programs	(522)	(11)
Decrease (increase) in program cash	0	0
Investment in vehicles	(3)	(1)
Proceeds received on disposition of vehicles	2	3
Net cash used in investing activities of vehicle programs	(1)	2
Net cash used in investing activities	(523)	(9)
Proceeds from long-term borrowings	2,725	654
Principal payments on borrowings	(2,243)	(651)
Net change in short-term borrowings	0	0
Purchase of warrants	0	0
Proceeds from sale of call options	0	0
Net intercompany transactions	(14)	(232)
Debt financing fees	(28)	(9)
Other, net	0
Net cash provided by financing activities exclusive of vehicle programs	440	(238)
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	440	(238)
Effect of changes in exchange rates on cash and cash equivalents	0	0
Net increase (decrease) in cash and cash equivalents	(38)	(195)
Cash and cash equivalents, beginning of period	102	234
Cash and cash equivalents, end of period	64	39
Guarantor Subsidiaries [Member]
Supplemental Guarantor Financial Information [Line Items]
Net cash provided by (used in) operating activities	(32)	27
Property and equipment additions	(24)	(16)
Proceeds received on asset sales	0	3
Payments to Acquire Restricted Investments	16	0
Other, net	43	(1)
Net cash used in investing activities exclusive of vehicle programs	35	(14)
Decrease (increase) in program cash	0	0
Investment in vehicles	(1)	(11)
Proceeds received on disposition of vehicles	0	1
Net cash used in investing activities of vehicle programs	(1)	(10)
Net cash used in investing activities	34	(24)
Proceeds from long-term borrowings	0	0
Principal payments on borrowings	(2)	(1)
Net change in short-term borrowings	0	0
Purchase of warrants	0	0
Proceeds from sale of call options	0
Net intercompany transactions	0	(1)
Debt financing fees	0	0
Other, net	0
Net cash provided by financing activities exclusive of vehicle programs	(2)	(2)
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	(2)	(2)
Effect of changes in exchange rates on cash and cash equivalents	0	0
Net increase (decrease) in cash and cash equivalents	0	1
Cash and cash equivalents, beginning of period	0	1
Cash and cash equivalents, end of period	0	2
Non-Guarantor Subsidiaries [Member]
Supplemental Guarantor Financial Information [Line Items]
Net cash used in investing activities	2,969
Net increase (decrease) in cash and cash equivalents	(67)
Non-Guarantor Subsidiaries [Member]
Supplemental Guarantor Financial Information [Line Items]
Net cash provided by (used in) operating activities	867	689
Property and equipment additions	(21)	(20)
Proceeds received on asset sales	4	6
Payments to Acquire Restricted Investments	21	(5)
Other, net	8	(3)
Net cash used in investing activities exclusive of vehicle programs	12	(22)
Decrease (increase) in program cash	111	(61)
Investment in vehicles	7,302	(6,926)
Proceeds received on disposition of vehicles	(4,432)	4,073
Net cash used in investing activities of vehicle programs	2,981	(2,914)
Net cash used in investing activities		(2,936)
Proceeds from long-term borrowings	0	0
Principal payments on borrowings	0	0
Net change in short-term borrowings	10	(1)
Purchase of warrants	0	0
Proceeds from sale of call options	0
Net intercompany transactions	(74)	1
Debt financing fees	0	0
Other, net	0
Net cash provided by financing activities exclusive of vehicle programs	(64)	0
Proceeds from borrowings	8,191	7,172
Principal payments on borrowings	(6,055)	(4,802)
Debt financing fees	(20)	(11)
Net cash provided by financing activities of vehicle programs	2,116	2,359
Net cash provided by financing activities	2,052	2,359
Effect of changes in exchange rates on cash and cash equivalents	(17)	1
Net increase (decrease) in cash and cash equivalents		113
Cash and cash equivalents, beginning of period	499	297
Cash and cash equivalents, end of period	432	410
Eliminations [Member]
Supplemental Guarantor Financial Information [Line Items]
Net cash provided by (used in) operating activities	(4)	(1)
Property and equipment additions	0	0
Proceeds received on asset sales	0	0
Payments to Acquire Restricted Investments	0	0
Other, net	0	0
Net cash used in investing activities exclusive of vehicle programs	0	0
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	0	0
Proceeds from long-term borrowings	0	0
Principal payments on borrowings	0	0
Net change in short-term borrowings	0	0
Purchase of warrants	0	0
Proceeds from sale of call options	0	0
Net intercompany transactions	4	1
Debt financing fees	0	0
Other, net	0
Net cash provided by financing activities exclusive of vehicle programs	4	1
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	1
Effect of changes in exchange rates on cash and cash equivalents	0	0
Net increase (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
Parent [Member]
Supplemental Guarantor Financial Information [Line Items]
Payments to Acquire Restricted Investments	$ 0	$ 0