Condensed Consolidating Financial Information - Statement of Cash Flows (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Condensed consolidating statement of cash flows
Net cash provided by (used in) continuing operating activities	$ 82.6	$ 193.3
Investing activities:
Purchase of equipment and improvements	(46.8)	(33.7)
Acquisitions, net	(0.4)	(86.4)
Other	(25.7)
Net cash used in continuing investing activities	(72.9)	(120.1)
Financing activities:
Net (repayments) borrowings of long-term debt	111.5	(139.3)
Net borrowings (repayments) of floor plan notes payable - non-trade	54.9	100.9
Payment of debt issuance costs		(1.2)
Repurchases of common stock	(167.9)	(14.0)
Dividends	(23.3)	(19.9)
Other	(4.6)
Net cash used in continuing financing activities	(29.4)	(73.5)
Net cash provided by (used in) discontinued operations	2.2	33.9
Effect of exchange rate changes on cash and cash equivalents	0.7	(3.1)
Net change in cash and cash equivalents	(16.8)	30.5
Cash and cash equivalents, beginning of period	62.4	36.3
Cash and cash equivalents, end of period	45.6	66.8
Penske Automotive Group
Condensed consolidating statement of cash flows
Net cash provided by (used in) continuing operating activities	(12.5)	(10.6)
Investing activities:
Purchase of equipment and improvements	(0.4)	(0.5)
Net cash used in continuing investing activities	(0.4)	(0.5)
Financing activities:
Net (repayments) borrowings of long-term debt	77.0
Net borrowings (repayments) of floor plan notes payable - non-trade	0.3	45.0
Repurchases of common stock	(167.9)	(14.0)
Dividends	(23.3)	(19.9)
Distributions from (to) parent	126.8
Net cash used in continuing financing activities	12.9	11.1
Guarantor Subsidiaries
Condensed consolidating statement of cash flows
Net cash provided by (used in) continuing operating activities	104.2	16.3
Investing activities:
Purchase of equipment and improvements	(26.4)	(19.2)
Acquisitions, net		(21.7)
Other	(0.3)
Net cash used in continuing investing activities	(26.7)	(40.9)
Financing activities:
Net (repayments) borrowings of long-term debt	21.2	(1.3)
Net borrowings (repayments) of floor plan notes payable - non-trade	28.5	(9.1)
Distributions from (to) parent	(126.8)	1.2
Net cash used in continuing financing activities	(77.1)	(9.2)
Net cash provided by (used in) discontinued operations	(0.4)	33.8
Non-Guarantor Subsidiaries
Condensed consolidating statement of cash flows
Net cash provided by (used in) continuing operating activities	(9.1)	187.6
Investing activities:
Purchase of equipment and improvements	(20.0)	(14.0)
Acquisitions, net	(0.4)	(64.7)
Other	(25.4)
Net cash used in continuing investing activities	(45.8)	(78.7)
Financing activities:
Net (repayments) borrowings of long-term debt	13.3	(138.0)
Net borrowings (repayments) of floor plan notes payable - non-trade	26.1	65.0
Payment of debt issuance costs		(1.2)
Other	(4.6)
Distributions from (to) parent		(1.2)
Net cash used in continuing financing activities	34.8	(75.4)
Net cash provided by (used in) discontinued operations	2.6	0.1
Effect of exchange rate changes on cash and cash equivalents	0.7	(3.1)
Net change in cash and cash equivalents	(16.8)	30.5
Cash and cash equivalents, beginning of period	62.4	36.3
Cash and cash equivalents, end of period	$ 45.6	$ 66.8