Derivatives (Effect of derivatives on consolidated statements of income) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014 gal		Dec. 31, 2013 gal		Dec. 31, 2012 gal
Swap
Derivative Instruments, Gain (Loss) [Line Items]
Derivative purchases of underlying commodity (in gallons)	10,500,000		9,700,000		6,300,000
Swap | Designated as hedging instrument | Cost of equipment rentals, excluding depreciation
Derivative Instruments, Gain (Loss) [Line Items]
Amount of income (expense) recognized on hedged item	(40)	[1],[2]	(38)	[1],[2]	(25)	[1],[2]
Foreign Exchange Forward | Not designated as hedging instrument | Other income (expense), net
Derivative Instruments, Gain (Loss) [Line Items]
Amount of income (expense) recognized on derivative	(7)		(3)
Amount of income (expense) recognized on hedged item	7		3

[1] Amounts recognized on hedged item reflect the use of 10.5 million, 9.7 million and 6.3 million gallons of diesel covered by the fixed price swaps during the years ended December 31, 2014, 2013 and 2012, respectively.

[2] Amounts recognized on derivative represent the effective portion of the fixed price diesel swaps.