Revenue (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Aug. 31, 2022	Aug. 31, 2021	Aug. 31, 2022	Aug. 31, 2021
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 8,144.8	$ 7,988.4	$ 17,456.4	$ 15,686.0
Used vehicle sales
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	6,284.1	6,104.4	13,298.6	12,261.7
Wholesale vehicle sales
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	1,690.3	1,701.6	3,806.8	3,075.9
Extended protection plan revenues
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	109.8	113.0	226.3	247.3
Third-party finance income, net
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	2.7	2.8	6.1	(1.8)
Advertising & subscription revenues [Domain]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	34.3	34.5	68.7	34.5
Service revenues
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	19.4	21.0	41.2	43.2
Other
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	4.2	11.1	8.7	25.1
Total other sales and revenues
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 170.4	$ 182.4	$ 351.0	$ 348.3