Revenues - Retail Automotive Dealership (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Revenues
Total revenues	$ 7,339.0	$ 6,975.4
Retail automotive dealership
Revenues
Total revenues	6,299.8	6,029.2	$ 23,700.0
Retail automotive dealership | U.S.
Revenues
Total revenues	3,378.2	3,343.6
Retail automotive dealership | U.K.
Revenues
Total revenues	2,472.4	2,262.9
Retail automotive dealership | Germany, Italy, and Japan
Revenues
Total revenues	449.2	422.7
New vehicle | Retail automotive dealership
Revenues
Total revenues	2,721.3	2,445.5
Used vehicle | Retail automotive dealership
Revenues
Total revenues	2,297.1	2,422.9
Finance and insurance, net | Retail automotive dealership
Revenues
Total revenues	206.8	217.3
Service and parts | Retail automotive dealership
Revenues
Total revenues	683.0	586.2
Fleet and wholesale | Retail automotive dealership
Revenues
Total revenues	$ 391.6	$ 357.3