Debt (Schedule of Debt) (Details) - USD ($)	Jun. 30, 2015	Jun. 15, 2015	Dec. 31, 2014	Dec. 31, 2013
Debt Instrument [Line Items]
Nominal Unpaid Principal Balance	$ 3,900,000,000		$ 3,900,000,000
Debt	17,682,000,000		15,993,000,000
Corporate Debt
Debt Instrument [Line Items]
Unamortized Net Discount	3,000,000		3,000,000
Debt	$ 6,618,000,000		6,431,000,000
Senior Term Facility
Debt Instrument [Line Items]
Average interest rate (as a percent)	3.68%
Nominal Unpaid Principal Balance	$ 2,072,000,000		2,083,000,000
Senior ABL Facility
Debt Instrument [Line Items]
Average interest rate (as a percent)	2.42%
Nominal Unpaid Principal Balance	$ 547,000,000		344,000,000
Promissory Notes
Debt Instrument [Line Items]
Average interest rate (as a percent)	7.00%
Nominal Unpaid Principal Balance	$ 27,000,000		27,000,000
Other Corporate Debt
Debt Instrument [Line Items]
Average interest rate (as a percent)	3.86%
Nominal Unpaid Principal Balance	$ 69,000,000		74,000,000
Fleet Debt
Debt Instrument [Line Items]
Unamortized Net Discount	(9,000,000)		(7,000,000)
Debt	11,064,000,000		9,562,000,000
U.S. Fleet Medium Term Notes
Debt Instrument [Line Items]
Nominal Unpaid Principal Balance	1,670,000,000		2,258,000,000
U.S. Fleet Medium Term Notes Series 2009-2 Notes
Debt Instrument [Line Items]
Nominal Unpaid Principal Balance	$ 0		404,000,000
U.S. Fleet Medium Term Notes Series 2010-1 Notes
Debt Instrument [Line Items]
Average interest rate (as a percent)	4.23%
Nominal Unpaid Principal Balance	$ 490,000,000		490,000,000
U.S. Fleet Medium Term Notes Series 2011-1 Notes
Debt Instrument [Line Items]
Average interest rate (as a percent)	3.51%
Nominal Unpaid Principal Balance	$ 230,000,000		414,000,000
U.S. Fleet Medium Term Notes Series 2013-1 Notes
Debt Instrument [Line Items]
Average interest rate (as a percent)	1.68%
Nominal Unpaid Principal Balance	$ 950,000,000		950,000,000
RCFC U.S. ABS Program
Debt Instrument [Line Items]
Nominal Unpaid Principal Balance	0		433,000,000
RCFC Series 2011-1 Notes
Debt Instrument [Line Items]
Nominal Unpaid Principal Balance	0		167,000,000	$ 500,000,000
RCFC Series 2011-2 Notes
Debt Instrument [Line Items]
Nominal Unpaid Principal Balance	0		266,000,000	$ 400,000,000
HVF II U.S. ABS Program
Debt Instrument [Line Items]
Nominal Unpaid Principal Balance	$ 5,220,000,000		3,844,000,000
HVF II Series 2013-A
Debt Instrument [Line Items]
Average interest rate (as a percent)	1.12%
Nominal Unpaid Principal Balance	$ 1,374,000,000		1,999,000,000
HVF II Series 2013-B
Debt Instrument [Line Items]
Average interest rate (as a percent)	1.12%
Nominal Unpaid Principal Balance	$ 1,400,000,000		976,000,000
HVF II Series 2014-A
Debt Instrument [Line Items]
Average interest rate (as a percent)	1.42%
Nominal Unpaid Principal Balance	$ 2,446,000,000		869,000,000
HVF II Us Fleet Variable Medium Term Notes
Debt Instrument [Line Items]
Nominal Unpaid Principal Balance	$ 780,000,000		0
Us Fleet Medium Term Notes 2015 Series 2
Debt Instrument [Line Items]
Average interest rate (as a percent)	2.93%
Nominal Unpaid Principal Balance	$ 780,000,000		0
Donlen ABS Program
Debt Instrument [Line Items]
Nominal Unpaid Principal Balance	$ 160,000,000		247,000,000
HFLF Series 2013-2 Notes
Debt Instrument [Line Items]
Average interest rate (as a percent)	1.05%
Nominal Unpaid Principal Balance	$ 160,000,000		247,000,000
HFLF Medium Term Notes
Debt Instrument [Line Items]
Nominal Unpaid Principal Balance	$ 1,027,000,000		900,000,000
HFLF Series 2013-A Notes
Debt Instrument [Line Items]
Average interest rate (as a percent)	0.83%
Nominal Unpaid Principal Balance	$ 370,000,000		500,000,000
HFLF Series 2014-1 Notes
Debt Instrument [Line Items]
Average interest rate (as a percent)	0.71%
Nominal Unpaid Principal Balance	$ 368,000,000		400,000,000
HFLF Series 2015-1 Notes
Debt Instrument [Line Items]
Average interest rate (as a percent)	0.83%
Nominal Unpaid Principal Balance	$ 289,000,000	$ 300,000,000	0
Other Fleet Debt
Debt Instrument [Line Items]
Nominal Unpaid Principal Balance	$ 2,207,000,000		1,880,000,000
U.S. Fleet Financing Facility
Debt Instrument [Line Items]
Average interest rate (as a percent)	2.94%
Nominal Unpaid Principal Balance	$ 190,000,000		164,000,000
European Revolving Credit Facility
Debt Instrument [Line Items]
Average interest rate (as a percent)	2.55%
Nominal Unpaid Principal Balance	$ 380,000,000		304,000,000
European Fleet Notes
Debt Instrument [Line Items]
Average interest rate (as a percent)	4.375%
Nominal Unpaid Principal Balance	$ 475,000,000		517,000,000
European Securitization
Debt Instrument [Line Items]
Average interest rate (as a percent)	1.90%
Nominal Unpaid Principal Balance	$ 365,000,000		270,000,000
Canadian Securitization
Debt Instrument [Line Items]
Average interest rate (as a percent)	1.93%
Nominal Unpaid Principal Balance	$ 142,000,000		105,000,000
Dollar Thrifty Sponsored Canadian Securitization
Debt Instrument [Line Items]
Average interest rate (as a percent)	1.95%
Nominal Unpaid Principal Balance	$ 61,000,000		40,000,000
Australian Securitization
Debt Instrument [Line Items]
Average interest rate (as a percent)	3.71%
Nominal Unpaid Principal Balance	$ 93,000,000		112,000,000
Brazilian Fleet Financing
Debt Instrument [Line Items]
Average interest rate (as a percent)	17.55%
Nominal Unpaid Principal Balance	$ 9,000,000		11,000,000
Capitalized Leases
Debt Instrument [Line Items]
Average interest rate (as a percent)	3.19%
Nominal Unpaid Principal Balance	$ 501,000,000		364,000,000
Senior Notes
Debt Instrument [Line Items]
Average interest rate (as a percent)	6.58%
Nominal Unpaid Principal Balance	$ 3,900,000,000		3,900,000,000
4.25% Senior Notes due April 2018
Debt Instrument [Line Items]
Nominal Unpaid Principal Balance	$ 250,000,000		250,000,000
Interest rate (as a percentage)	4.25%
7.50% Senior Notes due October 2018
Debt Instrument [Line Items]
Nominal Unpaid Principal Balance	$ 700,000,000		700,000,000
Interest rate (as a percentage)	7.50%
6.75% Senior Notes due April 2019
Debt Instrument [Line Items]
Nominal Unpaid Principal Balance	$ 1,250,000,000		1,250,000,000
Interest rate (as a percentage)	6.75%
5.875% Senior Notes due October 2020
Debt Instrument [Line Items]
Nominal Unpaid Principal Balance	$ 700,000,000		700,000,000
Interest rate (as a percentage)	5.875%
7.375% Senior Notes due January 2021
Debt Instrument [Line Items]
Nominal Unpaid Principal Balance	$ 500,000,000		500,000,000
Interest rate (as a percentage)	7.375%
6.25% Senior Notes due October 2022
Debt Instrument [Line Items]
Nominal Unpaid Principal Balance	$ 500,000,000		$ 500,000,000
Interest rate (as a percentage)	6.25%