Auto Loan Receivables (Ending Managed Receivables By Major Credit Grade) (Details) - USD ($) $ in Millions	Aug. 31, 2021	Feb. 28, 2021
Financing Receivable, By Major Credit Grade [Line Items]
Financing Receivable, Originated in Current Fiscal Year	$ 4,488.0	$ 5,561.7
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	4,496.7	4,112.6
Financing Receivable, Originated Two Years before Latest Fiscal Year	3,192.8	2,337.2
Financing Receivable, Originated Three Years before Latest Fiscal Year	1,714.8	1,226.9
Financing Receivable, Originated Four Years before Latest Fiscal Year	805.3	494.9
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	286.8	113.9
Total ending managed receivables	$ 14,984.4	$ 13,847.2
Total ending managed receivables as percentage by major credit grade	100.00%	100.00%
Credit Grade A
Financing Receivable, By Major Credit Grade [Line Items]
Financing Receivable, Originated in Current Fiscal Year	$ 2,172.9	$ 2,782.0
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	2,229.5	2,146.5
Financing Receivable, Originated Two Years before Latest Fiscal Year	1,658.8	1,146.7
Financing Receivable, Originated Three Years before Latest Fiscal Year	823.5	568.9
Financing Receivable, Originated Four Years before Latest Fiscal Year	357.3	199.6
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	96.0	30.4
Total ending managed receivables	$ 7,338.0	$ 6,874.1
Total ending managed receivables as percentage by major credit grade	49.00%	49.60%
Credit Grade B
Financing Receivable, By Major Credit Grade [Line Items]
Financing Receivable, Originated in Current Fiscal Year	$ 1,640.6	$ 1,993.6
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	1,617.1	1,424.5
Financing Receivable, Originated Two Years before Latest Fiscal Year	1,109.1	870.1
Financing Receivable, Originated Three Years before Latest Fiscal Year	648.2	476.0
Financing Receivable, Originated Four Years before Latest Fiscal Year	322.2	195.5
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	120.1	49.2
Total ending managed receivables	$ 5,457.3	$ 5,008.9
Total ending managed receivables as percentage by major credit grade	36.40%	36.20%
Credit Grade C And Other
Financing Receivable, By Major Credit Grade [Line Items]
Financing Receivable, Originated in Current Fiscal Year	$ 674.5	$ 786.1
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	650.1	541.6
Financing Receivable, Originated Two Years before Latest Fiscal Year	424.9	320.4
Financing Receivable, Originated Three Years before Latest Fiscal Year	243.1	182.0
Financing Receivable, Originated Four Years before Latest Fiscal Year	125.8	99.8
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	70.7	34.3
Total ending managed receivables	$ 2,189.1	$ 1,964.2
Total ending managed receivables as percentage by major credit grade	14.60%	14.20%

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