Business Combinations - Pro Forma Information (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2024	Jun. 30, 2024
Summary of unaudited consolidated pro forma results of operations
Revenues	$ 7,964.7	$ 15,689.0
Net income attributable to Penske Automotive Group common stockholders	$ 245.8	$ 465.7
Net income per diluted common share (in dollars per share)	$ 3.67	$ 6.95

Amount, after tax, of pro forma income (loss) of combined entity as if acquisition date of business combination occurred as of beginning of period.

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