Depreciation of Revenue Earning Equipment and Lease Charges (Details 2) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Revenue earning equipment
Net gains included in adjustment of depreciation upon disposal of revenue earning equipment	$ 12.7	$ 30.9	$ 93.3	$ 93.3
Net increase (decrease) in depreciation expenses	(59.4)		(96.7)
Equipment Rental
Revenue earning equipment
Net gains included in adjustment of depreciation upon disposal of revenue earning equipment	3.0	4.6	10.4	7.3
Car Rental
Revenue earning equipment
Net gains included in adjustment of depreciation upon disposal of revenue earning equipment	$ 9.7	$ 26.3	$ 82.9	$ 86.0