Segment Information (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015 USD ($)	Jun. 30, 2014 USD ($)	Jun. 30, 2015 USD ($) segment	Jun. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)
Reconciliation of adjusted pre-tax income to income (loss) before income taxes
Number of reportable segments | segment			4
Revenues	$ 2,692	$ 2,830	$ 5,145	$ 5,366
Adjusted Pre-Tax Income (Loss)	153	217	158	243
Adjustments from Segment Totals to Consolidated [Abstract]
Adjusted Pre-Tax Income (Loss)	50	123	(35)	64
Depreciation of revenue earning equipment and lease charges, net	696	708	1,403	1,434
Assets	26,071		26,071		$ 24,080
Reportable segments
Reconciliation of adjusted pre-tax income to income (loss) before income taxes
Adjusted Pre-Tax Income (Loss)	278	323	403	472
Acquisition accounting
Adjustments from Segment Totals to Consolidated [Abstract]
Adjusted Pre-Tax Income (Loss)	(32)	(33)	(63)	(65)
Debt-related charges
Adjustments from Segment Totals to Consolidated [Abstract]
Adjusted Pre-Tax Income (Loss)	(16)	(12)	(32)	(23)
Restructuring and restructuring related charges
Adjustments from Segment Totals to Consolidated [Abstract]
Adjusted Pre-Tax Income (Loss)	(47)	(31)	(67)	(72)
Acquisition related costs and charges
Adjustments from Segment Totals to Consolidated [Abstract]
Adjusted Pre-Tax Income (Loss)	(1)	(2)	0	(8)
Equipment rental spin-off costs
Adjustments from Segment Totals to Consolidated [Abstract]
Adjusted Pre-Tax Income (Loss)	(8)	(12)	(17)	(12)
Impairment charges and asset write-downs
Adjustments from Segment Totals to Consolidated [Abstract]
Adjusted Pre-Tax Income (Loss)	0	(10)	(9)	(10)
Integration expenses
Adjustments from Segment Totals to Consolidated [Abstract]
Adjusted Pre-Tax Income (Loss)	(3)	(3)	(3)	(6)
Relocation costs
Adjustments from Segment Totals to Consolidated [Abstract]
Adjusted Pre-Tax Income (Loss)	(1)	(3)	(4)	(5)
Other
Adjustments from Segment Totals to Consolidated [Abstract]
Adjusted Pre-Tax Income (Loss)	5	12	2	22
Corporate
Reconciliation of adjusted pre-tax income to income (loss) before income taxes
Adjusted Pre-Tax Income (Loss)	(125)	(106)	(245)	(229)
Adjustments from Segment Totals to Consolidated [Abstract]
Assets	1,481		1,481		1,716
U.S. Car Rental
Reconciliation of adjusted pre-tax income to income (loss) before income taxes
Revenues	1,615	1,663	3,135	3,220
Adjusted Pre-Tax Income (Loss)	174	184	244	306
Adjustments from Segment Totals to Consolidated [Abstract]
Depreciation of revenue earning equipment and lease charges, net	398	391	819	815
Assets	14,916		14,916		13,712
International Car Rental
Reconciliation of adjusted pre-tax income to income (loss) before income taxes
Revenues	556	641	992	1,123
Adjusted Pre-Tax Income (Loss)	45	57	52	16
Adjustments from Segment Totals to Consolidated [Abstract]
Depreciation of revenue earning equipment and lease charges, net	101	124	196	238
Assets	4,201		4,201		3,358
Worldwide Equipment Rental
Reconciliation of adjusted pre-tax income to income (loss) before income taxes
Revenues	375	384	730	743
Adjusted Pre-Tax Income (Loss)	42	67	76	121
Adjustments from Segment Totals to Consolidated [Abstract]
Depreciation of revenue earning equipment and lease charges, net	81	79	157	157
Assets	3,939		3,939		3,836
All Other Operations
Reconciliation of adjusted pre-tax income to income (loss) before income taxes
Revenues	146	142	288	280
Adjusted Pre-Tax Income (Loss)	17	15	31	29
Adjustments from Segment Totals to Consolidated [Abstract]
Depreciation of revenue earning equipment and lease charges, net	116	$ 114	231	$ 224
Assets	$ 1,534		$ 1,534		$ 1,458