Auto Loan Receivables (Past Due Receivables) (Details) - USD ($) $ in Millions	Aug. 31, 2022	Feb. 28, 2022
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	$ 15,590.8	$ 15,022.3
Past due receivables as a percentage of total ending managed receivables	4.64%	4.02%
Financing Receivable, before Allowance for Credit Loss, Noncurrent	$ 758.5	$ 630.0
Financing Receivable, before Allowance for Credit Loss	$ 16,349.3	$ 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	95.36%	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	2.70%	2.50%
Financing Receivable, before Allowance for Credit Loss, Noncurrent	$ 441.2	$ 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	1.58%	1.21%
Financing Receivable, before Allowance for Credit Loss, Noncurrent	$ 258.5	$ 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	0.36%	0.31%
Financing Receivable, before Allowance for Credit Loss, Noncurrent	$ 58.8	$ 48.8
Core managed receivables
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	15,311.4	14,815.9
Financing Receivable, before Allowance for Credit Loss, Noncurrent	667.4	574.1
Financing Receivable, before Allowance for Credit Loss	15,978.8	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	392.8	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	224.3	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	50.3	45.0
Core managed receivables | Credit Grade A
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	8,119.0	7,711.9
Financing Receivable, before Allowance for Credit Loss, Noncurrent	33.3	37.8
Financing Receivable, before Allowance for Credit Loss	8,152.3	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	20.8	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	9.8	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	2.7	3.2
Core managed receivables | Credit Grade B
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	5,548.4	5,401.3
Financing Receivable, before Allowance for Credit Loss, Noncurrent	323.6	268.8
Financing Receivable, before Allowance for Credit Loss	5,872.0	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	199.0	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	100.7	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	23.9	19.9
Core managed receivables | Credit Grade C And Other
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	1,644.0	1,702.7
Financing Receivable, before Allowance for Credit Loss, Noncurrent	310.5	267.5
Financing Receivable, before Allowance for Credit Loss	1,954.5	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	173.0	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	113.8	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	23.7	21.9
Other managed receivables | Credit Grade C And Other
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	279.4	206.4
Financing Receivable, before Allowance for Credit Loss, Noncurrent	91.1	55.9
Financing Receivable, before Allowance for Credit Loss	370.5	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	48.4	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	34.2	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	$ 8.5	$ 3.8