Revenues - Retail Commercial Truck Dealership (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Revenues
Total revenues	$ 29,527.4	$ 27,814.8	$ 25,554.7
Retail commercial truck dealership
Revenues
Total revenues	3,684.3	3,541.3	2,465.7
New vehicle | Retail commercial truck dealership
Revenues
Total revenues	2,480.2	2,308.7	1,540.1
Used vehicle | Retail commercial truck dealership
Revenues
Total revenues	229.9	301.3	270.6
Finance and insurance, net | Retail commercial truck dealership
Revenues
Total revenues	21.9	20.5	16.8
Service and parts | Retail commercial truck dealership
Revenues
Total revenues	907.3	852.2	609.0
Other | Retail commercial truck dealership
Revenues
Total revenues	$ 45.0	$ 58.6	$ 29.2