Auto Loan Receivables (Past Due Receivables) (Details) - USD ($) $ in Millions	Nov. 30, 2024	Feb. 29, 2024
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	$ 16,886.9	$ 16,445.2
Past due receivables as a percentage of total ending managed receivables	4.90%	5.44%
Financing Receivable, before Allowance for Credit Loss, Noncurrent	$ 869.5	$ 946.6
Financing Receivable, before Allowance for Credit Loss	$ 17,756.4	$ 17,391.8
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	95.10%	94.56%
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	3.07%	3.07%
Financing Receivable, before Allowance for Credit Loss, Noncurrent	$ 544.9	$ 534.4
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	1.48%	1.93%
Financing Receivable, before Allowance for Credit Loss, Noncurrent	$ 263.1	$ 336.0
Greater Than Ninety Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Past due receivables as a percentage of total ending managed receivables	0.35%	0.44%
Financing Receivable, before Allowance for Credit Loss, Noncurrent	$ 61.5	$ 76.2
Core managed receivables
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	16,360.5	15,998.1
Financing Receivable, before Allowance for Credit Loss, Noncurrent	756.0	815.2
Financing Receivable, before Allowance for Credit Loss	17,116.5	16,813.3
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	475.4	466.3
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	226.8	283.0
Core managed receivables | Greater Than Ninety Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Noncurrent	53.8	65.9
Core managed receivables | Credit Grade A
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	9,560.3	9,088.1
Financing Receivable, before Allowance for Credit Loss, Noncurrent	55.4	53.0
Financing Receivable, before Allowance for Credit Loss	9,615.7	9,141.1
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	35.6	32.1
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	14.9	15.1
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	4.9	5.8
Core managed receivables | Credit Grade B
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	5,600.1	5,666.3
Financing Receivable, before Allowance for Credit Loss, Noncurrent	445.3	457.2
Financing Receivable, before Allowance for Credit Loss	6,045.4	6,123.5
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	284.4	271.3
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	129.6	149.4
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	31.3	36.5
Core managed receivables | Credit Grade C And Other
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	1,200.1	1,243.7
Financing Receivable, before Allowance for Credit Loss, Noncurrent	255.3	305.0
Financing Receivable, before Allowance for Credit Loss	1,455.4	1,548.7
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	155.4	162.9
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	82.3	118.5
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	17.6	23.6
Other managed receivables | Credit Grade C And Other
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	526.4	447.1
Financing Receivable, before Allowance for Credit Loss, Noncurrent	113.5	131.4
Financing Receivable, before Allowance for Credit Loss	639.9	578.5
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	69.5	68.1
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	36.3	53.0
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	$ 7.7	$ 10.3