Auto Loan Receivables (Past Due Receivables) (Details) - USD ($) $ in Millions	Aug. 31, 2021	Feb. 28, 2021
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	$ 14,576.2	$ 13,454.7
Total ending managed receivables	$ 14,984.4	$ 13,847.2
Past due receivables as a percentage of total ending managed receivables	2.72%	2.83%
Financing Receivable, before Allowance for Credit Loss, Noncurrent	$ 408.2	$ 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	97.28%	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	1.73%	1.78%
Financing Receivable, before Allowance for Credit Loss, Noncurrent	$ 258.7	$ 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	0.82%	0.86%
Financing Receivable, before Allowance for Credit Loss, Noncurrent	$ 123.3	$ 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	0.17%	0.19%
Financing Receivable, before Allowance for Credit Loss, Noncurrent	$ 26.2	$ 26.4
Credit Grade A
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	7,315.6	6,847.2
Total ending managed receivables	7,338.0	6,874.1
Financing Receivable, before Allowance for Credit Loss, Noncurrent	22.4	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	14.3	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	6.1	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	2.0	2.6
Credit Grade B
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	5,289.8	4,840.3
Total ending managed receivables	5,457.3	5,008.9
Financing Receivable, before Allowance for Credit Loss, Noncurrent	167.5	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	109.2	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	47.5	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	10.8	11.3
Credit Grade C And Other
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	1,970.8	1,767.2
Total ending managed receivables	2,189.1	1,964.2
Financing Receivable, before Allowance for Credit Loss, Noncurrent	218.3	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	135.2	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	69.7	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	$ 13.4	$ 12.5