Revenues - Retail Commercial Truck Dealership (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Revenues
Total revenues	$ 6,906.9	$ 6,987.5	$ 13,882.3	$ 12,761.3
Retail commercial truck dealership
Revenues
Total revenues	768.7	625.3	1,561.0	1,060.0
New vehicle | Retail commercial truck dealership
Revenues
Total revenues	447.3	399.2	919.0	646.7
Used vehicle | Retail commercial truck dealership
Revenues
Total revenues	78.7	59.0	179.0	110.0
Finance and insurance, net | Retail commercial truck dealership
Revenues
Total revenues	4.5	3.8	10.9	6.9
Service and parts | Retail commercial truck dealership
Revenues
Total revenues	219.6	157.3	416.6	281.9
Other | Retail commercial truck dealership
Revenues
Total revenues	$ 18.6	$ 6.0	$ 35.5	$ 14.5