Revenue (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Nov. 30, 2023	Nov. 30, 2022	Nov. 30, 2023	Nov. 30, 2022
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 6,148.5	$ 6,506.0	$ 20,909.4	$ 23,962.4
Used vehicle sales
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	4,832.1	5,204.6	16,424.7	18,503.2
Wholesale vehicle sales
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	1,165.2	1,152.2	4,001.5	4,959.1
Extended protection plan revenues
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	90.8	91.8	303.8	318.1
Third-party finance (fees)/income, net
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	(1.2)	1.0	(2.4)	7.1
Advertising & subscription revenues [Domain]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	36.7	33.3	101.6	101.9
Service revenues
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	20.3	19.6	63.8	60.8
Other
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	4.7	3.5	16.4	12.3
Total other sales and revenues
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 151.3	$ 149.2	$ 483.2	$ 500.2