Business combinations and divestitures (Pro Forma Impact) (Details) (USD $)	12 Months Ended							4 Months Ended		1 Months Ended		12 Months Ended			12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010		Aug. 31, 2012	Dec. 31, 2011 Donlen Corporation		Dec. 31, 2012 Dollar Thrifty		Dec. 31, 2012 Dollar Thrifty	Dec. 31, 2011 Dollar Thrifty	Nov. 19, 2012 Dollar Thrifty	Dec. 31, 2011 Acquisition-related Costs Donlen Corporation	Dec. 31, 2010 Acquisition-related Costs Donlen Corporation	Dec. 31, 2012 Acquisition-related Costs Dollar Thrifty	Dec. 31, 2011 Acquisition-related Costs Dollar Thrifty	Dec. 31, 2011 Deferred Revenue Eliminated Donlen Corporation	Dec. 31, 2010 Deferred Revenue Eliminated Donlen Corporation	Dec. 31, 2011 Deferred Income Eliminated Donlen Corporation	Dec. 31, 2010 Deferred Income Eliminated Donlen Corporation
Business Acquisition, Pro Forma Information [Abstract]
Revenue of acquiree since acquisition date, actual								$ 142,700,000	[1]	$ 170,600,000	[2]
Earnings or loss of acquiree since acquisition date								2,000,000	[1]	(25,900,000)	[2]
Pro forma revenue	10,193,300,000	[3]	9,920,300,000	[4]	7,904,300,000	[5]													3,200,000	8,700,000
Pro forma net income (loss)	409,100,000	[3]	200,700,000	[4]	(48,600,000)	[5]									(6,100,000)	(6,100,000)					(2,000,000)	(5,300,000)
Amortization of other intangible assets	84,096,000		70,039,000		64,713,000							38,900,000	44,400,000
Interest expense	649,892,000		699,718,000		773,427,000							72,700,000	79,100,000
Labor and Related Expense																	(46,700,000)	46,700,000
Per share price														$ 87.50
Cash and equivalents acquired in acquisition														404,000,000
Aggregate maximum borrowings							$ 1,950,000,000
Pro Forma Adjustments, Assumed Tax Rate												39.00%

[1] Donlen's actual earnings for the four months ended December 31, 2011 was impacted by certain charges related to the amortization expense associated with the acquired intangible assets and the fair value adjustment related to acquired software, as well as, the write-off of certain unamortized debt costs.

[2] Dollar Thrifty's actual earnings for the 43 days ended December 31, 2012 was impacted by certain charges related to the amortization expense associated with the acquired intangible assets and non-recurring compensation costs in connection with the merger.

[3] The unaudited pro forma financial information for the year ended December 31, 2012 combines the historical results of Hertz Holdings and Dollar Thrifty for the year ended December 31, 2012, and the effects of the pro forma adjustments listed below.

[4] The unaudited pro forma financial information for the year ended December 31, 2011 combines the historical results of Hertz Holdings, Donlen and Dollar Thrifty for the year ended December 31, 2011, and the effects of the pro forma adjustments listed below.

[5] The unaudited pro forma financial information for the year ended December 31, 2010 combines the historical results of Hertz Holdings and Donlen for the year ended December 31, 2010, and the effects of the pro forma adjustments listed below.