Revenues - Retail Commercial Truck Dealership (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Revenues
Total revenues	$ 7,447.8	$ 6,920.7	$ 22,255.3	$ 20,803.0
Retail commercial truck dealership
Revenues
Total revenues	964.7	1,019.5	2,779.5	2,580.5
New truck | Retail commercial truck dealership
Revenues
Total revenues	644.4	704.8	1,861.0	1,623.8
Used truck | Retail commercial truck dealership
Revenues
Total revenues	68.4	74.2	170.3	253.2
Finance and insurance, net | Retail commercial truck dealership
Revenues
Total revenues	5.9	5.5	15.9	16.4
Service and parts | Retail commercial truck dealership
Revenues
Total revenues	235.1	223.9	695.2	640.5
Other | Retail commercial truck dealership
Revenues
Total revenues	$ 10.9	$ 11.1	$ 37.1	$ 46.6