Auto Loan Receivables (Past Due Receivables) (Details) - USD ($) $ in Millions	Feb. 28, 2023	Feb. 28, 2022
Financing Receivable, Past Due [Line Items]
Total ending managed receivables	$ 16,767.9	$ 15,652.3
Past due receivables as a percentage of total ending managed receivables	5.00%	4.02%
Financing Receivable, before Allowance for Credit Loss, Current	$ 15,930.4	$ 15,022.3
Financing Receivable, before Allowance for Credit Loss, Noncurrent	$ 837.5	$ 630.0
Managed Receivables
Financing Receivable, Past Due [Line Items]
Item as percent of total ending managed receivables	100.00%	100.00%
Core managed receivables
Financing Receivable, Past Due [Line Items]
Total ending managed receivables	$ 16,329.2	$ 15,390.0
Financing Receivable, before Allowance for Credit Loss, Current	15,602.8	14,815.9
Financing Receivable, before Allowance for Credit Loss, Noncurrent	726.4	574.1
Core managed receivables | Credit Grade A [Member]
Financing Receivable, Past Due [Line Items]
Total ending managed receivables	8,489.9	7,749.7
Financing Receivable, before Allowance for Credit Loss, Current	8,450.3	7,711.9
Financing Receivable, before Allowance for Credit Loss, Noncurrent	39.6	37.8
Core managed receivables | Credit Grade B
Financing Receivable, Past Due [Line Items]
Total ending managed receivables	5,913.6	5,670.1
Financing Receivable, before Allowance for Credit Loss, Current	5,540.2	5,401.3
Financing Receivable, before Allowance for Credit Loss, Noncurrent	373.4	268.8
Core managed receivables | Credit Grade C And Other
Financing Receivable, Past Due [Line Items]
Total ending managed receivables	1,925.7	1,970.2
Financing Receivable, before Allowance for Credit Loss, Current	1,612.3	1,702.7
Financing Receivable, before Allowance for Credit Loss, Noncurrent	313.4	267.5
Other managed receivables | Credit Grade C And Other
Financing Receivable, Past Due [Line Items]
Total ending managed receivables	438.7	262.3
Financing Receivable, before Allowance for Credit Loss, Current	327.6	206.4
Financing Receivable, before Allowance for Credit Loss, Noncurrent	$ 111.1	$ 55.9
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	2.90%	2.50%
Financing Receivable, before Allowance for Credit Loss, Noncurrent	$ 486.8	$ 392.1
Thirty One To Sixty Days Past Due [Member] | Core managed receivables
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Noncurrent	426.2	359.1
Thirty One To Sixty Days Past Due [Member] | Core managed receivables | Credit Grade A [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Noncurrent	25.1	25.4
Thirty One To Sixty Days Past Due [Member] | Core managed receivables | Credit Grade B
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Noncurrent	225.7	173.3
Thirty One To Sixty Days Past Due [Member] | Core managed receivables | Credit Grade C And Other
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Noncurrent	175.4	160.4
Thirty One To Sixty Days Past Due [Member] | Other managed receivables | Credit Grade C And Other
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Noncurrent	$ 60.6	$ 33.0
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	1.71%	1.21%
Financing Receivable, before Allowance for Credit Loss, Noncurrent	$ 287.2	$ 189.1
Sixty One To Ninety Days Past Due [Member] | Core managed receivables
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Noncurrent	245.1	170.0
Sixty One To Ninety Days Past Due [Member] | Core managed receivables | Credit Grade A [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Noncurrent	10.6	9.2
Sixty One To Ninety Days Past Due [Member] | Core managed receivables | Credit Grade B
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Noncurrent	120.0	75.6
Sixty One To Ninety Days Past Due [Member] | Core managed receivables | Credit Grade C And Other
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Noncurrent	114.5	85.2
Sixty One To Ninety Days Past Due [Member] | Other managed receivables | Credit Grade C And Other
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Noncurrent	$ 42.1	$ 19.1
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	$ 63.5	$ 48.8
Greater Than Ninety Days Past Due [Member] | Core managed receivables
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Noncurrent	55.1	45.0
Greater Than Ninety Days Past Due [Member] | Core managed receivables | Credit Grade A [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Noncurrent	3.9	3.2
Greater Than Ninety Days Past Due [Member] | Core managed receivables | Credit Grade B
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Noncurrent	27.7	19.9
Greater Than Ninety Days Past Due [Member] | Core managed receivables | Credit Grade C And Other
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Noncurrent	23.5	21.9
Greater Than Ninety Days Past Due [Member] | Other managed receivables | Credit Grade C And Other
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss, Noncurrent	$ 8.4	$ 3.8
Financial Asset, 1 to 29 Days Past Due
Financing Receivable, Past Due [Line Items]
Past due receivables as a percentage of total ending managed receivables	95.00%	95.98%