Business Combinations - Pro Forma Information (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Business Combination, Asset Acquisition, and Joint Venture Formation [Abstract]
Revenues	$ 31,087.2	$ 31,790.3
Net income attributable to Penske Automotive Group common stockholders	$ 928.2	$ 1,091.1
Net income per diluted common share (in dollars per share)	$ 13.88	$ 16.05