Auto Loan Receivables (Past Due Receivables) (Details) - USD ($) $ in Millions	May 31, 2021	Feb. 28, 2021
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	$ 14,162.6	$ 13,454.7
Total ending managed receivables	14,465.9	13,847.2
Financing Receivable, Past Due	$ 303.3	$ 392.5
Past due receivables as a percentage of total ending managed receivables	2.10%	2.83%
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	97.90%	97.17%
Thirty One To Sixty Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	$ 198.6	$ 246.2
Past due receivables as a percentage of total ending managed receivables	1.37%	1.78%
Sixty One To Ninety Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	$ 84.7	$ 119.9
Past due receivables as a percentage of total ending managed receivables	0.59%	0.86%
Greater Than Ninety Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	$ 20.0	$ 26.4
Past due receivables as a percentage of total ending managed receivables	0.14%	0.19%
Credit Grade A
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	$ 7,038.9	$ 6,847.2
Total ending managed receivables	7,058.5	6,874.1
Financing Receivable, Past Due	19.6	26.9
Credit Grade A | Thirty One To Sixty Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	12.2	17.3
Credit Grade A | Sixty One To Ninety Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	5.7	7.0
Credit Grade A | Greater Than Ninety Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	1.7	2.6
Credit Grade B
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	5,143.3	4,840.3
Total ending managed receivables	5,273.0	5,008.9
Financing Receivable, Past Due	129.7	168.6
Credit Grade B | Thirty One To Sixty Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	86.2	108.9
Credit Grade B | Sixty One To Ninety Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	34.6	48.4
Credit Grade B | Greater Than Ninety Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	8.9	11.3
Credit Grade C And Other
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	1,980.4	1,767.2
Total ending managed receivables	2,134.4	1,964.2
Financing Receivable, Past Due	154.0	197.0
Credit Grade C And Other | Thirty One To Sixty Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	100.2	120.0
Credit Grade C And Other | Sixty One To Ninety Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	44.4	64.5
Credit Grade C And Other | Greater Than Ninety Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	$ 9.4	$ 12.5