Revenues - Retail Commercial Truck Dealership (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Revenues
Total revenues	$ 6,920.7	$ 6,497.3	$ 20,803.0	$ 19,258.6
Retail commercial truck dealership
Revenues
Total revenues	1,019.5	717.3	2,580.5	1,777.3
New truck | Retail commercial truck dealership
Revenues
Total revenues	704.8	464.1	1,623.8	1,110.8
Used truck | Retail commercial truck dealership
Revenues
Total revenues	74.2	81.2	253.2	191.2
Finance and insurance, net | Retail commercial truck dealership
Revenues
Total revenues	5.5	4.8	16.4	11.7
Service and parts | Retail commercial truck dealership
Revenues
Total revenues	223.9	160.9	640.5	442.8
Other | Retail commercial truck dealership
Revenues
Total revenues	$ 11.1	$ 6.3	$ 46.6	$ 20.8