Guarantor And Non-Guarantor Consolidating Condensed Financial Statements (Consolidating Condensed Statements Of Cash Flows) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Supplemental Guarantor Financial Information [Line Items]
Net cash provided by (used in) operating activities	$ 390	$ 300
Property and equipment additions	(36)	(21)
Proceeds received on asset sales	3	4
Payments to Acquire Restricted Investments	(124)	(476)
Proceeds from (Repayments of) Related Party Debt		0
Other, net	(7)	26
Net cash used in investing activities exclusive of vehicle programs	(164)	(467)
Decrease (increase) in program cash	12	(24)
Investment in vehicles	(3,275)	(3,111)
Proceeds received on disposition of vehicles	2,470	2,394
Net cash used in investing activities of vehicle programs	(793)	(741)
Net cash used in investing activities	(957)	(1,208)
Proceeds from long-term borrowings	295	1,225
Principal payments on borrowings	(5)	(788)
Net change in short-term borrowings	11	(31)
Purchase of warrants	0	(28)
Proceeds from sale of call options	0	37
Repurchases of common stock	(67)	0
Net intercompany transactions		0
Debt financing fees	(5)	(10)
Other, net	(1)	2
Net cash provided by financing activities exclusive of vehicle programs	228	407
Proceeds from borrowings	3,775	3,762
Principal payments on borrowings	(3,280)	(3,279)
Debt financing fees	(7)	(17)
Net cash provided by financing activities of vehicle programs	488	466
Net cash provided by financing activities	716	873
Effect of changes in exchange rates on cash and cash equivalents	(1)	(2)
Net increase (decrease) in cash and cash equivalents	148	(37)
Cash and cash equivalents, beginning of period	693	606
Cash and cash equivalents, end of period	841	569
Parent [Member]
Supplemental Guarantor Financial Information [Line Items]
Net cash provided by (used in) operating activities	2	(17)
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	57	96
Net cash used in investing activities exclusive of vehicle programs	57	96
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	57	96
Proceeds from long-term borrowings	0	0
Principal payments on borrowings	0	(89)
Net change in short-term borrowings	0	0
Purchase of warrants		(28)
Proceeds from sale of call options		37
Repurchases of common stock	(67)
Net intercompany transactions		0
Debt financing fees	0	0
Other, net	(1)	2
Net cash provided by financing activities exclusive of vehicle programs	(68)	(78)
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	(68)	(78)
Effect of changes in exchange rates on cash and cash equivalents	0	0
Net increase (decrease) in cash and cash equivalents	(9)	1
Cash and cash equivalents, beginning of period	14	5
Cash and cash equivalents, end of period	5	6
Subsidiary Issuers [Member]
Supplemental Guarantor Financial Information [Line Items]
Net cash provided by (used in) operating activities	284	(59)
Property and equipment additions	(3)	(5)
Proceeds received on asset sales	2	2
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	(8)	(447)
Decrease (increase) in program cash	0	0
Investment in vehicles	(1)	(1)
Proceeds received on disposition of vehicles	3	1
Net cash used in investing activities of vehicle programs	2	0
Net cash used in investing activities	(6)	(447)
Proceeds from long-term borrowings	0	1,225
Principal payments on borrowings	(4)	(698)
Net change in short-term borrowings	0	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	(10)
Other, net	(57)	(96)
Net cash provided by financing activities exclusive of vehicle programs	(61)	421
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	(61)	421
Effect of changes in exchange rates on cash and cash equivalents	0	0
Net increase (decrease) in cash and cash equivalents	217	(85)
Cash and cash equivalents, beginning of period	242	102
Cash and cash equivalents, end of period	459	17
Guarantor Subsidiaries [Member]
Supplemental Guarantor Financial Information [Line Items]
Net cash provided by (used in) operating activities	14	(25)
Property and equipment additions	(17)	(10)
Proceeds received on asset sales	0	0
Payments to Acquire Restricted Investments	0	16
Proceeds from (Repayments of) Related Party Debt		0
Other, net	0	28
Net cash used in investing activities exclusive of vehicle programs	(17)	34
Decrease (increase) in program cash	0	0
Investment in vehicles	(8)	0
Proceeds received on disposition of vehicles	0	0
Net cash used in investing activities of vehicle programs	(8)	0
Net cash used in investing activities	(25)	34
Proceeds from long-term borrowings	0	0
Principal payments on borrowings	(1)	(1)
Net change in short-term borrowings	0	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 financing activities exclusive of vehicle programs	(1)	(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	(1)	(1)
Effect of changes in exchange rates on cash and cash equivalents	0	0
Net increase (decrease) in cash and cash equivalents	(12)	8
Cash and cash equivalents, beginning of period	12	0
Cash and cash equivalents, end of period	0	8
Non-Guarantor Subsidiaries [Member]
Supplemental Guarantor Financial Information [Line Items]
Net cash provided by (used in) operating activities	90	401
Property and equipment additions	(16)	(6)
Proceeds received on asset sales	1	2
Payments to Acquire Restricted Investments	(124)	21
Proceeds from (Repayments of) Related Party Debt		0
Other, net	0	(1)
Net cash used in investing activities exclusive of vehicle programs	(139)	16
Decrease (increase) in program cash	12	(24)
Investment in vehicles	(3,266)	(3,110)
Proceeds received on disposition of vehicles	2,467	2,393
Net cash used in investing activities of vehicle programs	(787)	(741)
Net cash used in investing activities	(926)	(725)
Proceeds from long-term borrowings	295	0
Principal payments on borrowings	0	0
Net change in short-term borrowings	11	(31)
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	0
Net cash provided by financing activities exclusive of vehicle programs	301	(101)
Proceeds from borrowings	3,775	3,762
Principal payments on borrowings	(3,280)	(3,279)
Debt financing fees	(7)	(17)
Net cash provided by financing activities of vehicle programs	488	466
Net cash provided by financing activities	789	365
Effect of changes in exchange rates on cash and cash equivalents	(1)	(2)
Net increase (decrease) in cash and cash equivalents	(48)	39
Cash and cash equivalents, beginning of period	425	499
Cash and cash equivalents, end of period	377	538
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
Proceeds from (Repayments of) Related Party Debt		(70)
Other, net	(57)	(96)
Net cash used in investing activities exclusive of vehicle programs	(57)	(166)
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	(57)	(166)
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
Proceeds from sale of call options		0
Repurchases of common stock	0
Net intercompany transactions		70
Debt financing fees	0	0
Other, net	57	96
Net cash provided by financing activities exclusive of vehicle programs	57	166
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	57	166
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