Auto Loan Receivables (Past Due Receivables) (Details) - USD ($) $ in Millions	May 31, 2020	Feb. 29, 2020
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	$ 12,845.2
Total ending managed receivables	13,171.9	$ 13,617.8
Total past due	$ 326.7	$ 468.9
Past due receivables as a percentage of total ending managed receivables	2.48%	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	97.52%
Thirty One To Sixty Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total past due	$ 198.5	$ 296.4
Past due receivables as a percentage of total ending managed receivables	1.51%	2.18%
Sixty One To Ninety Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total past due	$ 90.2	$ 138.3
Past due receivables as a percentage of total ending managed receivables	0.68%	1.01%
Greater Than Ninety Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total past due	$ 38.0	$ 34.2
Past due receivables as a percentage of total ending managed receivables	0.29%	0.25%
Credit Grade A
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	$ 6,632.0
Total ending managed receivables	6,659.1	$ 6,915.9
Total past due	27.1
Credit Grade A | Thirty One To Sixty Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total past due	16.4
Credit Grade A | Sixty One To Ninety Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total past due	7.0
Credit Grade A | Greater Than Ninety Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total past due	3.7
Credit Grade B
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	4,554.5
Total ending managed receivables	4,699.9	4,841.2
Total past due	145.4
Credit Grade B | Thirty One To Sixty Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total past due	89.3
Credit Grade B | Sixty One To Ninety Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total past due	38.9
Credit Grade B | Greater Than Ninety Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total past due	17.2
Credit Grade C And Other
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	1,658.7
Total ending managed receivables	1,812.9	$ 1,860.7
Total past due	154.2
Credit Grade C And Other | Thirty One To Sixty Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total past due	92.8
Credit Grade C And Other | Sixty One To Ninety Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total past due	44.3
Credit Grade C And Other | Greater Than Ninety Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total past due	$ 17.1