The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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The amount of assets reported by an equity method investment of the entity.

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Amount of equity, including noncontrolling interest, reported by an equity method investment of the entity.

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The amount of gross profit (loss) reported by an equity method investment of the entity.

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The amount of revenue from sale of goods and services reduced by sales returns, allowances, and discounts reported by an equity method investment of the entity.

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The number of units or percentage investment held in the subsidiary by the limited liability company or limited partnership.

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Equity Method Investees (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Equity Method Investment
Equity method investments	$ 352.8us-gaap_EquityMethodInvestments	$ 346.9us-gaap_EquityMethodInvestments
Condensed income statement information
Revenues	6,620.1	6,177.0	6,043.4
Gross margin	2,181.4	2,043.5	1,897.3
Net income	357.2	304.0	284.2
Equity in net income of affiliates	40.8	30.7	27.6
Condensed balance sheet information
Current assets	1,242.0	1,194.2
Noncurrent assets	9,230.8	8,377.8
Total assets	10,472.8	9,572.0
Current liabilities	958.1	888.8
Noncurrent liabilities	7,276.8	6,517.5
Equity	2,237.9	2,165.7
Total liabilities and equity	10,472.8	9,572.0
Jacobs Group
Equity Method Investment
Ownership percentage of Equity Method Investment	50.00%
The Nix Group
Equity Method Investment
Ownership percentage of Equity Method Investment	50.00%
Ibericar Keldinich SL
Equity Method Investment
Ownership percentage of Equity Method Investment	50.00%
Penske Wynn Ferrari Maserati
Equity Method Investment
Ownership percentage of Equity Method Investment	50.00%
Max Cycles
Equity Method Investment
Ownership percentage of Equity Method Investment	50.00%
Penske Commercial Leasing Australia
Equity Method Investment
Ownership percentage of Equity Method Investment	45.00%
Penske Vehicle Services
Equity Method Investment
Ownership percentage of Equity Method Investment	31.00%
National Powersport Auctions
Equity Method Investment
Ownership percentage of Equity Method Investment	7.00%
Penske Truck Leasing Co., L.P. ("PTL")
Equity Method Investment
Equity method investments	279.5	268.8
Limited partnership interest (as a percent)	9.00%
Jacobs Group, The Nix Group, Ibericar Keldinich SL, Penske Wynn Ferrari Maserati, Max Cycles, Penske Commercial Leasing Australia, QEK Global Solutions, and National Powersport Auctions
Equity Method Investment
Equity method investments	$ 73.3	$ 78.1