Auto Loan Receivables (Past Due Receivables) (Details) - USD ($) $ in Millions	May 31, 2022	Feb. 28, 2022
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	$ 15,399.7	$ 15,022.3
Past due receivables as a percentage of total ending managed receivables	4.06%	4.02%
Financing Receivable, before Allowance for Credit Loss, Noncurrent	$ 652.3	$ 630.0
Financing Receivable, before Allowance for Credit Loss	$ 16,052.0	$ 15,652.3
Item As A Percent Of Total Ending Managed Receivables	100.00%	100.00%
One to Thirty Days Past Due
Financing Receivable, Past Due [Line Items]
Past due receivables as a percentage of total ending managed receivables	95.94%	95.98%
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	2.50%	2.50%
Financing Receivable, before Allowance for Credit Loss, Noncurrent	$ 400.9	$ 392.1
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	1.26%	1.21%
Financing Receivable, before Allowance for Credit Loss, Noncurrent	$ 202.9	$ 189.1
Greater Than Ninety Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Past due receivables as a percentage of total ending managed receivables	0.30%	0.31%
Financing Receivable, before Allowance for Credit Loss, Noncurrent	$ 48.5	$ 48.8
Core managed receivables
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	15,143.0	14,815.9
Financing Receivable, before Allowance for Credit Loss, Noncurrent	581.9	574.1
Financing Receivable, before Allowance for Credit Loss	15,724.9	15,390.0
Core managed receivables | Thirty One To Sixty Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Noncurrent	360.0	359.1
Core managed receivables | Sixty One To Ninety Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Noncurrent	179.0	170.0
Core managed receivables | Greater Than Ninety Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Noncurrent	42.9	45.0
Core managed receivables | Credit Grade A
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	7,901.3	7,711.9
Financing Receivable, before Allowance for Credit Loss, Noncurrent	32.3	37.8
Financing Receivable, before Allowance for Credit Loss	7,933.6	7,749.7
Core managed receivables | 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	21.6	25.4
Core managed receivables | 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	8.1	9.2
Core managed receivables | Credit Grade A | Greater Than Ninety Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Noncurrent	2.6	3.2
Core managed receivables | Credit Grade B
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	5,549.2	5,401.3
Financing Receivable, before Allowance for Credit Loss, Noncurrent	275.1	268.8
Financing Receivable, before Allowance for Credit Loss	5,824.3	5,670.1
Core managed receivables | 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	175.6	173.3
Core managed receivables | 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	79.5	75.6
Core managed receivables | Credit Grade B | Greater Than Ninety Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Noncurrent	20.0	19.9
Core managed receivables | Credit Grade C And Other
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	1,692.5	1,702.7
Financing Receivable, before Allowance for Credit Loss, Noncurrent	274.5	267.5
Financing Receivable, before Allowance for Credit Loss	1,967.0	1,970.2
Core managed receivables | 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	162.8	160.4
Core managed receivables | 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	91.4	85.2
Core managed receivables | 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	20.3	21.9
Other managed receivables | Credit Grade C And Other
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	256.7	206.4
Financing Receivable, before Allowance for Credit Loss, Noncurrent	70.4	55.9
Financing Receivable, before Allowance for Credit Loss	327.1	262.3
Other managed receivables | 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	40.9	33.0
Other managed receivables | 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	23.9	19.1
Other managed receivables | 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	$ 5.6	$ 3.8