Auto Loan Receivables (Past Due Receivables) (Details) - USD ($) $ in Millions	Nov. 30, 2023	Feb. 28, 2023
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	$ 16,487.7	$ 15,930.4
Past due receivables as a percentage of total ending managed receivables	5.81%	5.00%
Financing Receivable, before Allowance for Credit Loss, Noncurrent	$ 1,017.4	$ 837.5
Financing Receivable, before Allowance for Credit Loss	$ 17,505.1	$ 16,767.9
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	94.19%	95.00%
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	3.13%	2.90%
Financing Receivable, before Allowance for Credit Loss, Noncurrent	$ 548.4	$ 486.8
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	2.21%	1.71%
Financing Receivable, before Allowance for Credit Loss, Noncurrent	$ 387.0	$ 287.2
Greater Than Ninety Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Past due receivables as a percentage of total ending managed receivables	0.47%	0.39%
Financing Receivable, before Allowance for Credit Loss, Noncurrent	$ 82.0	$ 63.5
Core managed receivables
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	16,089.4	15,602.8
Financing Receivable, before Allowance for Credit Loss, Noncurrent	874.8	726.4
Financing Receivable, before Allowance for Credit Loss	16,964.2	16,329.2
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	480.3	426.2
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	324.7	245.1
Core managed receivables | Greater Than Ninety Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Noncurrent	69.8	55.1
Core managed receivables | Credit Grade A
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	9,079.3	8,450.3
Financing Receivable, before Allowance for Credit Loss, Noncurrent	52.3	39.6
Financing Receivable, before Allowance for Credit Loss	9,131.6	8,489.9
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	31.6	25.1
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	15.5	10.6
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	5.2	3.9
Core managed receivables | Credit Grade B
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	5,715.6	5,540.2
Financing Receivable, before Allowance for Credit Loss, Noncurrent	472.7	373.4
Financing Receivable, before Allowance for Credit Loss	6,188.3	5,913.6
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	270.6	225.7
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	165.0	120.0
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	37.1	27.7
Core managed receivables | Credit Grade C And Other
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	1,294.5	1,612.3
Financing Receivable, before Allowance for Credit Loss, Noncurrent	349.8	313.4
Financing Receivable, before Allowance for Credit Loss	1,644.3	1,925.7
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	178.1	175.4
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	144.2	114.5
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	27.5	23.5
Other managed receivables | Credit Grade C And Other
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	398.3	327.6
Financing Receivable, before Allowance for Credit Loss, Noncurrent	142.6	111.1
Financing Receivable, before Allowance for Credit Loss	540.9	438.7
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	68.1	60.6
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	62.3	42.1
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	$ 12.2	$ 8.4