Auto Loan Receivables (Past Due Receivables) (Details) - USD ($) $ in Millions	Aug. 31, 2023	Feb. 28, 2023
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	$ 16,492.9	$ 15,930.4
Past due receivables as a percentage of total ending managed receivables	5.45%	5.00%
Financing Receivable, before Allowance for Credit Loss, Noncurrent	$ 949.9	$ 837.5
Financing Receivable, before Allowance for Credit Loss	$ 17,442.8	$ 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	94.55%	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	2.94%	2.90%
Financing Receivable, before Allowance for Credit Loss, Noncurrent	$ 512.3	$ 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	2.06%	1.71%
Financing Receivable, before Allowance for Credit Loss, Noncurrent	$ 358.7	$ 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	0.45%	0.39%
Financing Receivable, before Allowance for Credit Loss, Noncurrent	$ 78.9	$ 63.5
Core managed receivables
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	16,128.9	15,602.8
Financing Receivable, before Allowance for Credit Loss, Noncurrent	817.8	726.4
Financing Receivable, before Allowance for Credit Loss	16,946.7	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	449.4	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	302.3	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	66.1	55.1
Core managed receivables | Credit Grade A
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	8,967.5	8,450.3
Financing Receivable, before Allowance for Credit Loss, Noncurrent	47.1	39.6
Financing Receivable, before Allowance for Credit Loss	9,014.6	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	29.1	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	14.1	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	3.9	3.9
Core managed receivables | Credit Grade B
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	5,751.2	5,540.2
Financing Receivable, before Allowance for Credit Loss, Noncurrent	424.7	373.4
Financing Receivable, before Allowance for Credit Loss	6,175.9	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	243.1	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	148.0	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	33.6	27.7
Core managed receivables | Credit Grade C And Other
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	1,410.2	1,612.3
Financing Receivable, before Allowance for Credit Loss, Noncurrent	346.0	313.4
Financing Receivable, before Allowance for Credit Loss	1,756.2	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	177.2	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	140.2	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	28.6	23.5
Other managed receivables | Credit Grade C And Other
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Current	364.0	327.6
Financing Receivable, before Allowance for Credit Loss, Noncurrent	132.1	111.1
Financing Receivable, before Allowance for Credit Loss	496.1	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	62.9	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	56.4	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	$ 12.8	$ 8.4