Revenues - Other Disclosures (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Revenues
Total revenues	$ 7,447.8	$ 6,920.7	$ 22,255.3	$ 20,803.0
Commercial vehicle distribution and other
Revenues
Payment period			30 days
Total revenues	157.7	143.4	$ 444.6	438.2
Vehicle Sales | Retail Automotive and Retail Commercial Truck Dealership
Revenues
Payment period			30 days
Service and parts | Retail Automotive and Retail Commercial Truck Dealership
Revenues
Payment period			30 days
Service and parts | Commercial vehicle distribution and other
Revenues
Total revenues	68.4	$ 62.7	$ 197.7	$ 178.3
Finance and insurance, net | Retail Automotive and Retail Commercial Truck Dealership
Revenues
Payment period			30 days
Aggregate reserves relating to chargeback activity	$ 41.8		$ 41.8		$ 38.4