Condensed Consolidating Financial Information (Details 3) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Condensed consolidating statement of cash flows
Net cash from continuing operating activities	$ 211.4	$ 174.0
Investing activities:
Purchase of equipment and improvements	(72.9)	(70.2)
Purchase of car rental vehicles	(76.3)	(73.2)
Acquisitions, net	(86.2)	(30.7)
Other	24.9	(9.7)
Net cash used in continuing investing activities	(210.5)	(183.8)
Financing activities:
Net borrowings (repayments) of long-term debt	(3.1)	(11.2)
Net borrowings (repayments) of floor plan notes payable - non-trade	32.4	37.6
Repurchases of common stock	(15.5)	(15.8)
Dividends	(33.5)	(26.2)
Other	0.3	0.2
Net cash used in continuing financing activities	(19.4)	(15.4)
Net cash provided by discontinued operations	30.1	7.7
Net change in cash and cash equivalents	11.6	(17.5)
Cash and cash equivalents, beginning of period	49.8	43.8
Cash and cash equivalents, end of period	61.4	26.3
Reportable legal entities | Penske Automotive Group
Condensed consolidating statement of cash flows
Net cash from continuing operating activities	33.6	72.1
Investing activities:
Purchase of equipment and improvements	(0.4)	(0.7)
Other	4.1
Net cash used in continuing investing activities	3.7	(0.7)
Financing activities:
Net borrowings (repayments) of long-term debt	10.0	(40.0)
Net borrowings (repayments) of floor plan notes payable - non-trade	1.7	10.6
Repurchases of common stock	(15.5)	(15.8)
Dividends	(33.5)	(26.2)
Net cash used in continuing financing activities	(37.3)	(71.4)
Reportable legal entities | Guarantor Subsidiaries
Condensed consolidating statement of cash flows
Net cash from continuing operating activities	95.8	52.4
Investing activities:
Purchase of equipment and improvements	(51.8)	(45.9)
Purchase of car rental vehicles	(76.3)	(73.2)
Acquisitions, net	(80.5)	(29.3)
Other	20.8	(15.5)
Net cash used in continuing investing activities	(187.8)	(163.9)
Financing activities:
Net borrowings (repayments) of long-term debt	45.1	80.3
Net borrowings (repayments) of floor plan notes payable - non-trade	14.6	(5.7)
Distributions from (to) parent	3.6	0.3
Net cash used in continuing financing activities	63.3	74.9
Net cash provided by discontinued operations	16.1	1.9
Net change in cash and cash equivalents	(12.6)	(34.7)
Cash and cash equivalents, beginning of period	12.6	34.7
Reportable legal entities | Non-Guarantor Subsidiaries
Condensed consolidating statement of cash flows
Net cash from continuing operating activities	82.0	49.5
Investing activities:
Purchase of equipment and improvements	(20.7)	(23.6)
Acquisitions, net	(5.7)	(1.4)
Other		5.8
Net cash used in continuing investing activities	(26.4)	(19.2)
Financing activities:
Net borrowings (repayments) of long-term debt	(58.2)	(51.5)
Net borrowings (repayments) of floor plan notes payable - non-trade	16.1	32.7
Distributions from (to) parent	(3.6)	(0.3)
Other	0.3	0.2
Net cash used in continuing financing activities	(45.4)	(18.9)
Net cash provided by discontinued operations	14.0	5.8
Net change in cash and cash equivalents	24.2	17.2
Cash and cash equivalents, beginning of period	37.2	9.1
Cash and cash equivalents, end of period	$ 61.4	$ 26.3