Guarantor And Non-Guarantor Consolidating Condensed Financial Statements (Consolidating Condensed Statements Of Cash Flows) (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Supplemental Guarantor Financial Information [Line Items]
Net cash provided by (used in) operating activities	$ 1,743	$ 1,524
Property and equipment additions	(92)	(82)
Proceeds received on asset sales	13	16
Payments to Acquire Restricted Investments	(531)	(5)
Other, net	37	(25)
Net cash used in investing activities exclusive of vehicle programs	(573)	(96)
Decrease (increase) in program cash	(173)	(90)
Investment in vehicles	(8,865)	(8,962)
Proceeds received on disposition of vehicles	6,393	6,136
Net cash used in investing activities of vehicle programs	(2,645)	(2,916)
Net cash used in investing activities	(3,218)	(3,012)
Proceeds from long-term borrowings	2,725	654
Principal payments on borrowings	(2,344)	(907)
Net change in short-term borrowings	(32)	1
Purchase of warrants	(30)	(26)
Proceeds from sale of call options	41	38
Payments for Repurchase of Common Stock	(21)	0
Net intercompany transactions	0	0
Debt financing fees	(36)	(11)
Other, net	(2)	(1)
Net cash provided by financing activities exclusive of vehicle programs	305	(250)
Proceeds from borrowings	10,266	9,238
Principal payments on borrowings	(9,079)	(7,467)
Debt financing fees	(26)	(18)
Net cash provided by financing activities of vehicle programs	1,161	1,753
Net cash provided by financing activities	1,466	1,503
Effect of changes in exchange rates on cash and cash equivalents	(8)	5
Net increase (decrease) in cash and cash equivalents	(17)	20
Cash and cash equivalents, beginning of period	606	534
Cash and cash equivalents, end of period	589	554
Parent [Member]
Supplemental Guarantor Financial Information [Line Items]
Net cash provided by (used in) operating activities	(4)	(48)
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	(94)	(201)
Net change in short-term borrowings	0	0
Purchase of warrants	(30)	(26)
Proceeds from sale of call options	41	38
Payments for Repurchase of Common Stock	(21)
Net intercompany transactions	108	234
Debt financing fees	0	0
Other, net	(2)	(1)
Net cash provided by financing activities exclusive of vehicle programs	6	46
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	6	46
Effect of changes in exchange rates on cash and cash equivalents	0	0
Net increase (decrease) in cash and cash equivalents	2	2
Cash and cash equivalents, beginning of period	5	2
Cash and cash equivalents, end of period	7	4
Subsidiary Issuers [Member]
Supplemental Guarantor Financial Information [Line Items]
Net cash provided by (used in) operating activities	448	128
Property and equipment additions	(17)	(19)
Proceeds received on asset sales	4	5
Payments to Acquire Restricted Investments	(563)	0
Other, net	(13)	(3)
Net cash used in investing activities exclusive of vehicle programs	(589)	(17)
Decrease (increase) in program cash	0	0
Investment in vehicles	(40)	(2)
Proceeds received on disposition of vehicles	22	4
Net cash used in investing activities of vehicle programs	(18)	2
Net cash used in investing activities	(607)	(15)
Proceeds from long-term borrowings	2,400	654
Principal payments on borrowings	(2,248)	(704)
Net change in short-term borrowings	0	0
Purchase of warrants	0	0
Proceeds from sale of call options	0	0
Payments for Repurchase of Common Stock	0
Net intercompany transactions	(32)	(234)
Debt financing fees	(29)	(11)
Other, net	0	0
Net cash provided by financing activities exclusive of vehicle programs	91	(295)
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	91	(295)
Effect of changes in exchange rates on cash and cash equivalents	0	0
Net increase (decrease) in cash and cash equivalents	(68)	(182)
Cash and cash equivalents, beginning of period	102	234
Cash and cash equivalents, end of period	34	52
Guarantor Subsidiaries [Member]
Supplemental Guarantor Financial Information [Line Items]
Net cash provided by (used in) operating activities	2	42
Property and equipment additions	(43)	(26)
Proceeds received on asset sales	0	3
Payments to Acquire Restricted Investments	8	0
Other, net	47	(1)
Net cash used in investing activities exclusive of vehicle programs	12	(24)
Decrease (increase) in program cash	0	0
Investment in vehicles	(2)	(19)
Proceeds received on disposition of vehicles	0	2
Net cash used in investing activities of vehicle programs	(2)	(17)
Net cash used in investing activities	10	(41)
Proceeds from long-term borrowings	0	0
Principal payments on borrowings	(2)	(2)
Net change in short-term borrowings	0	0
Purchase of warrants	0	0
Proceeds from sale of call options	0
Payments for Repurchase of Common Stock	0
Net intercompany transactions	0	0
Debt financing fees	0	0
Other, net	0	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	10	(1)
Cash and cash equivalents, beginning of period	0	1
Cash and cash equivalents, end of period	10	0
Non-Guarantor Subsidiaries [Member]
Supplemental Guarantor Financial Information [Line Items]
Net cash provided by (used in) operating activities	1,300	1,402
Property and equipment additions	(32)	(37)
Proceeds received on asset sales	9	8
Payments to Acquire Restricted Investments	24	(5)
Other, net	3	(25)
Net cash used in investing activities exclusive of vehicle programs	4	(59)
Decrease (increase) in program cash	(173)	(90)
Investment in vehicles	(8,823)	(8,941)
Proceeds received on disposition of vehicles	6,371	6,130
Net cash used in investing activities of vehicle programs	(2,625)	(2,901)
Net cash used in investing activities	(2,621)	(2,960)
Proceeds from long-term borrowings	325	0
Principal payments on borrowings	0	0
Net change in short-term borrowings	(32)	1
Purchase of warrants	0	0
Proceeds from sale of call options	0
Payments for Repurchase of Common Stock	0
Net intercompany transactions	(79)	0
Debt financing fees	(7)	0
Other, net	0	0
Net cash provided by financing activities exclusive of vehicle programs	207	1
Proceeds from borrowings	10,266	9,238
Principal payments on borrowings	(9,079)	(7,467)
Debt financing fees	(26)	(18)
Net cash provided by financing activities of vehicle programs	1,161	1,753
Net cash provided by financing activities	1,368	1,754
Effect of changes in exchange rates on cash and cash equivalents	(8)	5
Net increase (decrease) in cash and cash equivalents	39	201
Cash and cash equivalents, beginning of period	499	297
Cash and cash equivalents, end of period	538	498
Eliminations [Member]
Supplemental Guarantor Financial Information [Line Items]
Net cash provided by (used in) operating activities	(3)	0
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
Payments for Repurchase of Common Stock	0
Net intercompany transactions	3	0
Debt financing fees	0	0
Other, net	0	0
Net cash provided by financing activities exclusive of vehicle programs	3	0
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	3	0
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