Business Combinations - Pro Forma Information (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
Mar. 31, 2024	Mar. 31, 2023
Summary of unaudited consolidated pro forma results of operations
Revenues	$ 7,468.2	$ 7,688.4
Net income attributable to Penske Automotive Group common stockholders	$ 215.4	$ 304.6
Net income per diluted common share (in dollars per share)	$ 3.21	$ 4.40

The pro forma diluted net income per share for a period as if the business combination or combinations had been completed at the beginning of a period.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (h)(2)
-SubTopic 10
-Topic 805
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479328/805-10-50-2

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (h)(3)
-SubTopic 10
-Topic 805
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479328/805-10-50-2

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The pro forma net Income or Loss for the period as if the business combination or combinations had been completed at the beginning of a period.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 805
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (h)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479328/805-10-50-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 805
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (h)(3)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479328/805-10-50-2

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The pro forma revenue for a period as if the business combination or combinations had been completed at the beginning of the period.

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