Business combinations and divestitures (Acquisition) (Details) (USD $)	0 Months Ended	12 Months Ended								0 Months Ended	11 Months Ended		0 Months Ended			0 Months Ended
	Nov. 19, 2012	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2013	Jun. 28, 2013	May 30, 2013	Aug. 31, 2012	Nov. 19, 2012 Dollar Thrifty	Nov. 19, 2012 Dollar Thrifty	Nov. 19, 2013 Dollar Thrifty	Sep. 01, 2011 Donlen Corporation	May 02, 2013 China Auto	Nov. 19, 2012 Trade name Dollar Thrifty	Nov. 19, 2012 Concession rights Dollar Thrifty
Acquisition
Per share price										$ 87.50	$ 87.50
Recognized identifieable assets acquired, goodwill and liabiliteis assumed, net												$ 2,592,000,000	$ 250,000,000
Payments to acquire business	2,551,000,000
Cash and equivalents acquired in acquisition										404,000,000	404,000,000
Remeasurement gain	8,400,000
Equity interest in acquiree, fair value										41,000,000
Aggregate maximum borrowings							300,000,000	100,000,000	1,950,000,000
Proceeds from issuance of debt											1,950,000,000
Other intangible assets												1,545,000,000	75,000,000		1,140,000,000	405,000,000
Useful life (in years)																9 years
Goodwill		1,329,300,000		392,100,000		1,347,500,000						889,000,000	51,100,000
Percentage of voting interests acquired													100.00%	10.00%
Consideration transferred													250,000,000
Pro forma revenue		10,197,400,000	[1]	9,920,500,000	[2]
Pro forma net income (loss)		$ 437,300,000	[1]	$ 223,100,000	[2]
Business Combination, Step Acquisition, Equity Interest in Acquiree, Including Subsequent Acquisition, Percentage														18.64%

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

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