Auto Loan Receivables (Ending Managed Receivables By Major Credit Grade) (Details) - USD ($) $ in Millions	Nov. 30, 2022	Feb. 28, 2022
Financing Receivable, By Major Credit Grade [Line Items]
Financing Receivable, Originated in Current Fiscal Year	$ 6,052.1	$ 7,765.0
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	5,630.7	3,596.9
Financing Receivable, Originated Two Years before Latest Fiscal Year	2,527.1	2,453.3
Financing Receivable, Originated Three Years before Latest Fiscal Year	1,582.9	1,227.7
Financing Receivable, Originated Four Years before Latest Fiscal Year	664.2	492.4
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	195.7	117.0
Financing Receivable, before Allowance for Credit Loss	$ 16,652.7	$ 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	$ 5,829.7	$ 7,599.8
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	5,503.5	3,573.0
Financing Receivable, Originated Two Years before Latest Fiscal Year	2,510.2	2,418.6
Financing Receivable, Originated Three Years before Latest Fiscal Year	1,559.1	1,203.9
Financing Receivable, Originated Four Years before Latest Fiscal Year	648.7	482.4
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	189.1	112.3
Financing Receivable, before Allowance for Credit Loss	$ 16,240.3	$ 15,390.0
Total ending managed receivables as percentage by major credit grade	97.50%	98.30%
Credit Grade A | Core managed receivables
Financing Receivable, By Major Credit Grade [Line Items]
Financing Receivable, Originated in Current Fiscal Year	$ 3,154.3	$ 3,885.5
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	2,815.6	1,788.3
Financing Receivable, Originated Two Years before Latest Fiscal Year	1,252.9	1,266.1
Financing Receivable, Originated Three Years before Latest Fiscal Year	800.6	574.1
Financing Receivable, Originated Four Years before Latest Fiscal Year	290.0	203.4
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	63.4	32.3
Financing Receivable, before Allowance for Credit Loss	$ 8,376.8	$ 7,749.7
Total ending managed receivables as percentage by major credit grade	50.30%	49.50%
Credit Grade B | Core managed receivables
Financing Receivable, By Major Credit Grade [Line Items]
Financing Receivable, Originated in Current Fiscal Year	$ 2,079.9	$ 2,795.2
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	2,020.1	1,288.5
Financing Receivable, Originated Two Years before Latest Fiscal Year	907.2	857.7
Financing Receivable, Originated Three Years before Latest Fiscal Year	564.1	473.1
Financing Receivable, Originated Four Years before Latest Fiscal Year	268.0	205.2
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	87.4	50.4
Financing Receivable, before Allowance for Credit Loss	$ 5,926.7	$ 5,670.1
Total ending managed receivables as percentage by major credit grade	35.60%	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	$ 595.5	$ 919.1
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	667.8	496.2
Financing Receivable, Originated Two Years before Latest Fiscal Year	350.1	294.8
Financing Receivable, Originated Three Years before Latest Fiscal Year	194.4	156.7
Financing Receivable, Originated Four Years before Latest Fiscal Year	90.7	73.8
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	38.3	29.6
Financing Receivable, before Allowance for Credit Loss	$ 1,936.8	$ 1,970.2
Total ending managed receivables as percentage by major credit grade	11.60%	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	$ 222.4	$ 165.2
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	127.2	23.9
Financing Receivable, Originated Two Years before Latest Fiscal Year	16.9	34.7
Financing Receivable, Originated Three Years before Latest Fiscal Year	23.8	23.8
Financing Receivable, Originated Four Years before Latest Fiscal Year	15.5	10.0
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	6.6	4.7
Financing Receivable, before Allowance for Credit Loss	$ 412.4	$ 262.3
Total ending managed receivables as percentage by major credit grade	2.50%	1.70%