Condensed Consolidating Financial Information - Balance Sheet (Details) - USD ($) $ in Millions	Jun. 30, 2016	May 31, 2016	Dec. 31, 2015	Jun. 30, 2015	Dec. 31, 2014	Nov. 30, 2014	Aug. 31, 2012
Condensed consolidating balance sheet
Cash and cash equivalents	$ 97.5		$ 62.4	$ 39.4	$ 36.3
Accounts receivable, net	827.8		782.3
Inventories	3,351.8		3,463.5
Other current assets	101.7		85.6
Assets held for sale	6.8		12.7
Total current assets	4,385.6		4,406.5
Property and equipment, net	1,576.7		1,520.1
Intangible assets	1,722.2		1,731.2
Equity method investments	371.1		336.4
Other long-term assets	19.6		19.2
Total assets	8,075.2		8,013.4
Floor plan notes payable	2,061.8		2,247.2
Floor plan notes payable - non-trade	969.4		1,132.4
Accounts payable	554.8		493.8
Accrued expenses	403.3		378.1
Current portion of long-term debt	47.7		28.0
Liabilities held for sale	4.6		6.2
Total current liabilities	4,041.6		4,285.7
Long-term debt	1,613.1		1,247.0
Deferred tax liabilities	449.4		433.4
Other long-term liabilities	238.2		212.4
Total liabilities	6,342.3		6,178.5
Total equity	1,732.9		1,834.9
Total liabilities and equity	$ 8,075.2		$ 8,013.4
5.75% senior subordinated notes due 2022
Condensed consolidating balance sheet
Interest rate (as a percent)	5.75%		5.75%				5.75%
Domestic Subsidiaries ownership guaranteeing obligations (as a percent)	100.00%
5.375% Senior Subordinated Notes Due 2024
Condensed consolidating balance sheet
Interest rate (as a percent)	5.375%		5.375%			5.375%
Domestic Subsidiaries ownership guaranteeing obligations (as a percent)	100.00%
5.50% senior subordinated notes due 2026
Condensed consolidating balance sheet
Interest rate (as a percent)	5.50%	5.50%
Domestic Subsidiaries ownership guaranteeing obligations (as a percent)	100.00%
Eliminations
Condensed consolidating balance sheet
Accounts receivable, net	$ (439.7)		$ (430.4)
Total current assets	(439.7)		(430.4)
Other long-term assets	(2,316.0)		(2,253.4)
Total assets	(2,755.7)		(2,683.8)
Accrued expenses	(439.7)		(430.4)
Total current liabilities	(439.7)		(430.4)
Long-term debt	(160.7)		(256.4)
Total liabilities	(600.4)		(686.8)
Total equity	(2,155.3)		(1,997.0)
Total liabilities and equity	(2,755.7)		(2,683.8)
Reportable legal entities | Penske Automotive Group
Condensed consolidating balance sheet
Accounts receivable, net	439.7		430.4
Other current assets	3.2		3.9
Total current assets	442.9		434.3
Property and equipment, net	3.6		4.0
Equity method investments	309.6		298.2
Other long-term assets	2,322.1		2,259.9
Total assets	3,078.2		2,996.4
Floor plan notes payable - non-trade	5.0		154.7
Accounts payable	2.6		4.8
Accrued expenses	0.9		0.1
Total current liabilities	8.5		159.6
Long-term debt	1,336.8		1,001.9
Total liabilities	1,345.3		1,161.5
Total equity	1,732.9		1,834.9
Total liabilities and equity	3,078.2		2,996.4
Reportable legal entities | Guarantor Subsidiaries
Condensed consolidating balance sheet
Cash and cash equivalents	11.2
Accounts receivable, net	414.8		400.8
Inventories	1,911.5		1,650.5
Other current assets	33.5		28.3
Assets held for sale	6.8		8.5
Total current assets	2,377.8		2,088.1
Property and equipment, net	950.9		822.0
Intangible assets	1,099.9		878.9
Other long-term assets	7.6		7.2
Total assets	4,436.2		3,796.2
Floor plan notes payable	1,213.7		1,295.0
Floor plan notes payable - non-trade	549.1		339.8
Accounts payable	176.2		143.3
Accrued expenses	171.1		112.3
Current portion of long-term debt	11.2		5.7
Liabilities held for sale	4.4		4.4
Total current liabilities	2,125.7		1,900.5
Long-term debt	196.1		109.2
Deferred tax liabilities	433.7		413.4
Other long-term liabilities	64.5		68.9
Total liabilities	2,820.0		2,492.0
Total equity	1,616.2		1,304.2
Total liabilities and equity	4,436.2		3,796.2
Reportable legal entities | Non-Guarantor Subsidiaries
Condensed consolidating balance sheet
Cash and cash equivalents	86.3		62.4	$ 39.4	$ 36.3
Accounts receivable, net	413.0		381.5
Inventories	1,440.3		1,813.0
Other current assets	65.0		53.4
Assets held for sale			4.2
Total current assets	2,004.6		2,314.5
Property and equipment, net	622.2		694.1
Intangible assets	622.3		852.3
Equity method investments	61.5		38.2
Other long-term assets	5.9		5.5
Total assets	3,316.5		3,904.6
Floor plan notes payable	848.1		952.2
Floor plan notes payable - non-trade	415.3		637.9
Accounts payable	376.0		345.7
Accrued expenses	671.0		696.1
Current portion of long-term debt	36.5		22.3
Liabilities held for sale	0.2		1.8
Total current liabilities	2,347.1		2,656.0
Long-term debt	240.9		392.3
Deferred tax liabilities	15.7		20.0
Other long-term liabilities	173.7		143.5
Total liabilities	2,777.4		3,211.8
Total equity	539.1		692.8
Total liabilities and equity	$ 3,316.5		$ 3,904.6