Condensed Consolidating Financial Information - Statement of Income (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Condensed consolidating statement of income
Revenues	$ 5,081.1	$ 4,824.6
Cost of sales	4,306.8	4,100.8
Gross profit	774.3	723.8
Selling, general and administrative expenses	601.7	558.9
Depreciation	22.4	20.8
Operating income	150.2	144.1
Floor plan interest expense	(13.7)	(12.8)
Other interest expense	(25.0)	(17.2)
Equity in earnings of affiliates	13.2	5.5
Income from continuing operations before income taxes	124.7	119.6
Income taxes	(41.1)	(39.4)
Income from continuing operations	83.6	80.2
Loss from discontinued operations, net of tax	(0.6)
Net income	83.0	80.2
Other comprehensive income (loss), net of tax	26.1	1.2
Comprehensive income	109.1	81.4
Less: Comprehensive income attributable to non-controlling interests	0.8	2.4
Comprehensive income attributable to Penske Automotive Group common stockholders	108.3	79.0
Penske Automotive Group
Condensed consolidating statement of income
Selling, general and administrative expenses	6.0	6.1
Depreciation	0.4	0.4
Operating income	(6.4)	(6.5)
Floor plan interest expense	(1.0)	(0.8)
Other interest expense	(16.5)	(13.3)
Equity in earnings of affiliates	12.5	4.2
Equity in earnings of subsidiaries	135.7	135.1
Income from continuing operations before income taxes	124.3	118.7
Income taxes	(41.1)	(39.4)
Income from continuing operations	83.2	79.3
Loss from discontinued operations, net of tax	(0.6)	(0.1)
Net income	82.6	79.2
Other comprehensive income (loss), net of tax	26.1	1.2
Comprehensive income	108.7	80.4
Less: Comprehensive income attributable to non-controlling interests	0.4	1.5
Comprehensive income attributable to Penske Automotive Group common stockholders	108.3	78.9
Guarantor Subsidiaries
Condensed consolidating statement of income
Revenues	2,667.9	2,389.2
Cost of sales	2,231.2	2,006.2
Gross profit	436.7	383.0
Selling, general and administrative expenses	338.4	295.8
Depreciation	12.7	10.8
Operating income	85.6	76.4
Floor plan interest expense	(8.4)	(6.7)
Other interest expense	(2.1)	1.3
Income from continuing operations before income taxes	75.1	71.0
Income taxes	(32.6)	(29.2)
Income from continuing operations	42.5	41.8
Loss from discontinued operations, net of tax	(0.6)	0.1
Net income	41.9	41.9
Comprehensive income	41.9	41.9
Comprehensive income attributable to Penske Automotive Group common stockholders	41.9	41.9
Non-Guarantor Subsidiaries
Condensed consolidating statement of income
Revenues	2,413.2	2,435.4
Cost of sales	2,075.6	2,094.6
Gross profit	337.6	340.8
Selling, general and administrative expenses	257.3	257.0
Depreciation	9.3	9.6
Operating income	71.0	74.2
Floor plan interest expense	(4.3)	(5.3)
Other interest expense	(6.4)	(5.2)
Equity in earnings of affiliates	0.7	1.3
Income from continuing operations before income taxes	61.0	65.0
Income taxes	(12.3)	(15.6)
Income from continuing operations	48.7	49.4
Loss from discontinued operations, net of tax		(0.1)
Net income	48.7	49.3
Other comprehensive income (loss), net of tax	23.5	(0.3)
Comprehensive income	72.2	49.0
Less: Comprehensive income attributable to non-controlling interests	0.8	2.4
Comprehensive income attributable to Penske Automotive Group common stockholders	71.4	46.6
Eliminations
Condensed consolidating statement of income
Equity in earnings of subsidiaries	(135.7)	(135.1)
Income from continuing operations before income taxes	(135.7)	(135.1)
Income taxes	44.9	44.8
Income from continuing operations	(90.8)	(90.3)
Loss from discontinued operations, net of tax	0.6	0.1
Net income	(90.2)	(90.2)
Other comprehensive income (loss), net of tax	(23.5)	0.3
Comprehensive income	(113.7)	(89.9)
Less: Comprehensive income attributable to non-controlling interests	(0.4)	(1.5)
Comprehensive income attributable to Penske Automotive Group common stockholders	$ (113.3)	$ (88.4)