Auto Loan Receivables (Ending Managed Receivables By Major Credit Grade) (Details) - USD ($) $ in Millions	Aug. 31, 2022	Feb. 28, 2022
Financing Receivable, By Major Credit Grade [Line Items]
Financing Receivable, Originated in Current Fiscal Year	$ 4,370.3	$ 7,765.0
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	6,208.6	3,596.9
Financing Receivable, Originated Two Years before Latest Fiscal Year	2,825.3	2,453.3
Financing Receivable, Originated Three Years before Latest Fiscal Year	1,828.0	1,227.7
Financing Receivable, Originated Four Years before Latest Fiscal Year	823.3	492.4
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	293.8	117.0
Financing Receivable, before Allowance for Credit Loss	$ 16,349.3	$ 15,652.3
Total ending managed receivables as percentage by major credit grade	100.00%	100.00%
Core managed receivables
Financing Receivable, By Major Credit Grade [Line Items]
Financing Receivable, Originated in Current Fiscal Year	$ 4,215.3	$ 7,599.8
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	6,065.4	3,573.0
Financing Receivable, Originated Two Years before Latest Fiscal Year	2,806.4	2,418.6
Financing Receivable, Originated Three Years before Latest Fiscal Year	1,801.2	1,203.9
Financing Receivable, Originated Four Years before Latest Fiscal Year	805.4	482.4
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	285.1	112.3
Financing Receivable, before Allowance for Credit Loss	$ 15,978.8	$ 15,390.0
Total ending managed receivables as percentage by major credit grade	97.70%	98.30%
Credit Grade A | Core managed receivables
Financing Receivable, By Major Credit Grade [Line Items]
Financing Receivable, Originated in Current Fiscal Year	$ 2,242.3	$ 3,885.5
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	3,097.9	1,788.3
Financing Receivable, Originated Two Years before Latest Fiscal Year	1,405.5	1,266.1
Financing Receivable, Originated Three Years before Latest Fiscal Year	934.1	574.1
Financing Receivable, Originated Four Years before Latest Fiscal Year	369.8	203.4
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	102.7	32.3
Financing Receivable, before Allowance for Credit Loss	$ 8,152.3	$ 7,749.7
Total ending managed receivables as percentage by major credit grade	49.80%	49.50%
Credit Grade B | Core managed receivables
Financing Receivable, By Major Credit Grade [Line Items]
Financing Receivable, Originated in Current Fiscal Year	$ 1,533.9	$ 2,795.2
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	2,227.8	1,288.5
Financing Receivable, Originated Two Years before Latest Fiscal Year	1,010.7	857.7
Financing Receivable, Originated Three Years before Latest Fiscal Year	645.1	473.1
Financing Receivable, Originated Four Years before Latest Fiscal Year	326.3	205.2
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	128.2	50.4
Financing Receivable, before Allowance for Credit Loss	$ 5,872.0	$ 5,670.1
Total ending managed receivables as percentage by major credit grade	35.90%	36.20%
Credit Grade C And Other | Core managed receivables
Financing Receivable, By Major Credit Grade [Line Items]
Financing Receivable, Originated in Current Fiscal Year	$ 439.1	$ 919.1
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	739.7	496.2
Financing Receivable, Originated Two Years before Latest Fiscal Year	390.2	294.8
Financing Receivable, Originated Three Years before Latest Fiscal Year	222.0	156.7
Financing Receivable, Originated Four Years before Latest Fiscal Year	109.3	73.8
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	54.2	29.6
Financing Receivable, before Allowance for Credit Loss	$ 1,954.5	$ 1,970.2
Total ending managed receivables as percentage by major credit grade	12.00%	12.60%
Credit Grade C And Other | Other managed receivables
Financing Receivable, By Major Credit Grade [Line Items]
Financing Receivable, Originated in Current Fiscal Year	$ 155.0	$ 165.2
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	143.2	23.9
Financing Receivable, Originated Two Years before Latest Fiscal Year	18.9	34.7
Financing Receivable, Originated Three Years before Latest Fiscal Year	26.8	23.8
Financing Receivable, Originated Four Years before Latest Fiscal Year	17.9	10.0
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	8.7	4.7
Financing Receivable, before Allowance for Credit Loss	$ 370.5	$ 262.3
Total ending managed receivables as percentage by major credit grade	2.30%	1.70%