Consolidated Statements Of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Cash Flows [Abstract]
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	$ 901	$ 720	$ 717
Operating activities
Net income	361	163	313
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Vehicle depreciation	1,947	1,877	1,837
(Gain) loss on sale of vehicles, net	52	(10)	(60)
Non-vehicle related depreciation and amortization	259	253	218
Deferred income taxes	(192)	51	58
Stock-based compensation	13	27	28
Amortization of debt financing fees	34	37	42
Early extinguishment of debt costs	3	27	23
Net change in assets and liabilities, excluding the impact of acquisitions and dispositions:
Receivables	(59)	(65)	(42)
Income taxes	(16)	5	(18)
Accounts payable and other current liabilities	49	2	(36)
Other, net	197	273	264
Net cash provided by operating activities	2,648	2,640	2,627
Investing activities
Property and equipment additions	(197)	(190)	(199)
Proceeds received on asset sales	8	19	15
Net assets acquired (net of cash acquired)	(21)	(55)	(256)
Other, net	5	1	3
Net cash used in investing activities exclusive of vehicle programs	(205)	(225)	(437)
Vehicle programs:
Investment in vehicles	(11,538)	(12,461)	(11,928)
Proceeds received on disposition of vehicles	9,600	10,504	9,680
Repayments of Related Party Debt	(61)	0	0
Net Cash Used In Investing Activities Of Vehicle Programs	(1,999)	(1,957)	(2,248)
Net cash used in investing activities	(2,204)	(2,182)	(2,685)
Financing activities
Proceeds from long-term borrowings	589	894	377
Payments on long-term borrowings	(602)	(847)	(301)
Net change in short-term borrowings	(4)	4	(22)
Debt financing fees	(9)	(20)	(7)
Repurchases of common stock	(210)	(398)	(436)
Other, net	1	0	(7)
Net cash used in financing activities exclusive of vehicle programs	(235)	(367)	(396)
Vehicle programs:
Proceeds from borrowings	17,212	15,769	14,138
Payments on borrowings	(17,269)	(15,826)	(13,648)
Debt financing fees	(16)	(25)	(22)
Net cash provided by financing activities of vehicle programs	(73)	(82)	468
Net cash provided by (used in) financing activities	(308)	(449)	72
Effect of changes in exchange rates on cash and cash equivalents, program and restricted cash	45	(6)	(50)
Net increase (decrease) in cash and cash equivalents, program and restricted cash	181	3	(36)
Cash and cash equivalents, program and restricted cash, end of period	611	490
Supplemental Disclosure
Interest payments	460	461	454
Income tax payments, net	$ 58	$ 60	$ 29