Auto Loan Receivables (Past Due Receivables) (Details) - USD ($) $ in Millions	Nov. 30, 2021	Feb. 28, 2021
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	$ 14,929.6	$ 13,454.7
Total ending managed receivables	$ 15,524.0	$ 13,847.2
Past due receivables as a percentage of total ending managed receivables	3.83%	2.83%
Financing Receivable, before Allowance for Credit Loss, Noncurrent	$ 594.4	$ 392.5
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	96.17%	97.17%
Thirty One To Sixty Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Past due receivables as a percentage of total ending managed receivables	2.34%	1.78%
Financing Receivable, before Allowance for Credit Loss, Noncurrent	$ 363.1	$ 246.2
Sixty One To Ninety Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Past due receivables as a percentage of total ending managed receivables	1.20%	0.86%
Financing Receivable, before Allowance for Credit Loss, Noncurrent	$ 186.0	$ 119.9
Greater Than Ninety Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Past due receivables as a percentage of total ending managed receivables	0.29%	0.19%
Financing Receivable, before Allowance for Credit Loss, Noncurrent	$ 45.3	$ 26.4
Credit Grade A
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	7,617.6	6,847.2
Total ending managed receivables	7,652.6	6,874.1
Financing Receivable, before Allowance for Credit Loss, Noncurrent	35.0	26.9
Credit Grade A | Thirty One To Sixty Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Noncurrent	23.0	17.3
Credit Grade A | Sixty One To Ninety Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Noncurrent	9.2	7.0
Credit Grade A | Greater Than Ninety Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Noncurrent	2.8	2.6
Credit Grade B
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	5,373.2	4,840.3
Total ending managed receivables	5,626.4	5,008.9
Financing Receivable, before Allowance for Credit Loss, Noncurrent	253.2	168.6
Credit Grade B | Thirty One To Sixty Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Noncurrent	160.4	108.9
Credit Grade B | Sixty One To Ninety Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Noncurrent	74.5	48.4
Credit Grade B | Greater Than Ninety Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Noncurrent	18.3	11.3
Credit Grade C And Other
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	1,938.8	1,767.2
Total ending managed receivables	2,245.0	1,964.2
Financing Receivable, before Allowance for Credit Loss, Noncurrent	306.2	197.0
Credit Grade C And Other | Thirty One To Sixty Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Noncurrent	179.7	120.0
Credit Grade C And Other | Sixty One To Ninety Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Noncurrent	102.3	64.5
Credit Grade C And Other | Greater Than Ninety Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Noncurrent	$ 24.2	$ 12.5