Auto Loan Receivables (Past Due Receivables) (Details) - USD ($) $ in Millions	Nov. 30, 2022	Feb. 28, 2022
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	$ 15,820.9	$ 15,022.3
Past due receivables as a percentage of total ending managed receivables	4.99%	4.02%
Financing Receivable, before Allowance for Credit Loss, Noncurrent	$ 831.8	$ 630.0
Financing Receivable, before Allowance for Credit Loss	$ 16,652.7	$ 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	95.01%	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	2.85%	2.50%
Financing Receivable, before Allowance for Credit Loss, Noncurrent	$ 474.1	$ 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	1.75%	1.21%
Financing Receivable, before Allowance for Credit Loss, Noncurrent	$ 292.1	$ 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	0.39%	0.31%
Financing Receivable, before Allowance for Credit Loss, Noncurrent	$ 65.6	$ 48.8
Core managed receivables
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	15,516.1	14,815.9
Financing Receivable, before Allowance for Credit Loss, Noncurrent	724.2	574.1
Financing Receivable, before Allowance for Credit Loss	16,240.3	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	416.8	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	250.7	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	56.7	45.0
Core managed receivables | Credit Grade A
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	8,340.4	7,711.9
Financing Receivable, before Allowance for Credit Loss, Noncurrent	36.4	37.8
Financing Receivable, before Allowance for Credit Loss	8,376.8	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	21.7	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	11.6	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	3.1	3.2
Core managed receivables | Credit Grade B
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	5,570.5	5,401.3
Financing Receivable, before Allowance for Credit Loss, Noncurrent	356.2	268.8
Financing Receivable, before Allowance for Credit Loss	5,926.7	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	211.9	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	116.4	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	27.9	19.9
Core managed receivables | Credit Grade C And Other
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	1,605.2	1,702.7
Financing Receivable, before Allowance for Credit Loss, Noncurrent	331.6	267.5
Financing Receivable, before Allowance for Credit Loss	1,936.8	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	183.2	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	122.7	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	25.7	21.9
Other managed receivables | Credit Grade C And Other
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	304.8	206.4
Financing Receivable, before Allowance for Credit Loss, Noncurrent	107.6	55.9
Financing Receivable, before Allowance for Credit Loss	412.4	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	57.3	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	41.4	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	$ 8.9	$ 3.8