Auto Loan Receivables (Past Due Receivables) (Details) - USD ($) $ in Millions	Aug. 31, 2020	Feb. 29, 2020
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	$ 13,028.8
Total ending managed receivables	13,379.0	$ 13,617.8
Total past due	$ 350.2	$ 468.9
Past due receivables as a percentage of total ending managed receivables	2.62%	3.44%
Total ending managed receivables, percent
Financing Receivable, Past Due [Line Items]
Item as percent of total ending managed receivables	100.00%	100.00%
Financial Asset, Current
Financing Receivable, Past Due [Line Items]
Past due receivables as a percentage of total ending managed receivables	97.38%
Thirty One To Sixty Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total past due	$ 213.8	$ 296.4
Past due receivables as a percentage of total ending managed receivables	1.60%	2.18%
Sixty One To Ninety Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total past due	$ 106.3	$ 138.3
Past due receivables as a percentage of total ending managed receivables	0.79%	1.01%
Greater Than Ninety Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total past due	$ 30.1	$ 34.2
Past due receivables as a percentage of total ending managed receivables	0.23%	0.25%
Credit Grade A
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	$ 6,713.9
Total ending managed receivables	6,739.6	$ 6,915.9
Total past due	25.7
Credit Grade A | Thirty One To Sixty Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total past due	15.7
Credit Grade A | Sixty One To Ninety Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total past due	7.2
Credit Grade A | Greater Than Ninety Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total past due	2.8
Credit Grade B
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	4,663.4
Total ending managed receivables	4,814.1	4,841.2
Total past due	150.7
Credit Grade B | Thirty One To Sixty Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total past due	94.2
Credit Grade B | Sixty One To Ninety Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total past due	43.5
Credit Grade B | Greater Than Ninety Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total past due	13.0
Credit Grade C And Other
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	1,651.5
Total ending managed receivables	1,825.3	$ 1,860.7
Total past due	173.8
Credit Grade C And Other | Thirty One To Sixty Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total past due	103.9
Credit Grade C And Other | Sixty One To Ninety Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total past due	55.6
Credit Grade C And Other | Greater Than Ninety Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total past due	$ 14.3