Derivatives (Effect of derivatives on consolidated statements of income) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012		Mar. 31, 2011
Swap [Member] | Designated as hedging instruments [Member] | Cost of equipment rentals excluding depreciation (2), (3) [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of income (expese) recognized on hedged item	$ (5)	[1],[2]	$ (3)	[1],[2]
Foreign Exchange Forward [Member] | Not designated as hedging instruments [Member] | Other income (expense), net [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of income (expense) recognized on derivative	0		4
Amount of income (expese) recognized on hedged item	$ 0		$ (4)

[1] Amounts recognized on hedged item reflect the use of 1.2 million and 0.9 million gallons of diesel covered by the fixed price swaps during the three months ended March 31, 2012 and 2011, respectively.

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