v3.25.2
REVENUES - Schedule of Revenues Disaggregated by Revenue Source and Geographical Segment (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Disaggregation of Revenue        
Total revenues $ 5,703.5 $ 4,696.4 $ 11,208.8 $ 9,166.9
U.S.        
Disaggregation of Revenue        
Total revenues 4,177.2 3,921.2 8,098.9 7,566.9
U.K.        
Disaggregation of Revenue        
Total revenues 1,526.4 775.2 3,109.9 1,600.0
Total new and used vehicle sales        
Disaggregation of Revenue        
Total revenues 4,747.4 3,921.7 9,334.4 7,627.1
Total new and used vehicle sales | U.S.        
Disaggregation of Revenue        
Total revenues 3,422.7 3,239.9 6,627.7 6,219.1
Total new and used vehicle sales | U.K.        
Disaggregation of Revenue        
Total revenues 1,324.8 681.8 2,706.7 1,408.0
New vehicle retail sales        
Disaggregation of Revenue        
Total revenues 2,735.5 2,364.2 5,415.4 4,546.8
New vehicle retail sales | U.S.        
Disaggregation of Revenue        
Total revenues 2,132.9 2,009.5 4,101.6 3,809.4
New vehicle retail sales | U.K.        
Disaggregation of Revenue        
Total revenues 602.5 354.6 1,313.8 737.4
Used vehicle retail sales        
Disaggregation of Revenue        
Total revenues 1,848.2 1,453.2 3,603.6 2,870.0
Used vehicle retail sales | U.S.        
Disaggregation of Revenue        
Total revenues 1,203.2 1,151.9 2,347.6 2,251.4
Used vehicle retail sales | U.K.        
Disaggregation of Revenue        
Total revenues 645.0 301.3 1,256.0 618.6
Used vehicle wholesale sales        
Disaggregation of Revenue        
Total revenues 163.8 104.3 315.4 210.3
Used vehicle wholesale sales | U.S.        
Disaggregation of Revenue        
Total revenues 86.5 78.4 178.5 158.3
Used vehicle wholesale sales | U.K.        
Disaggregation of Revenue        
Total revenues 77.3 25.9 136.9 52.0
Parts and service sales        
Disaggregation of Revenue        
Total revenues 718.4 574.5 1,410.4 1,150.8
Parts and service sales | U.S.        
Disaggregation of Revenue        
Total revenues 555.5 497.4 1,086.8 992.6
Parts and service sales | U.K.        
Disaggregation of Revenue        
Total revenues 162.8 77.1 323.7 158.2
Finance, insurance and other, net        
Disaggregation of Revenue        
Total revenues 237.8 200.1 464.0 389.0
Variable consideration recognized 5.1 5.6 15.5 18.0
Finance, insurance and other, net | U.S.        
Disaggregation of Revenue        
Total revenues 199.0 183.9 384.5 355.2
Finance, insurance and other, net | U.K.        
Disaggregation of Revenue        
Total revenues $ 38.8 $ 16.3 $ 79.5 $ 33.8