Auto Loan Receivables (Ending Managed Receivables By Major Credit Grade) (Details) - USD ($) $ in Millions	Feb. 28, 2022	Feb. 28, 2021
Financing Receivable, By Major Credit Grade [Line Items]
Total ending managed receivables	$ 15,652.3	$ 13,847.2
Total ending managed receivables as percentage by major credit grade	100.00%	100.00%
Financing Receivable, Year One, Originated, Current Fiscal Year	$ 7,765.0	$ 5,561.7
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	3,596.9	4,112.6
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	2,453.3	2,337.2
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	1,227.7	1,226.9
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	492.4	494.9
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	117.0	113.9
Core managed receivables
Financing Receivable, By Major Credit Grade [Line Items]
Total ending managed receivables	$ 15,390.0	$ 13,682.7
Total ending managed receivables as percentage by major credit grade	98.30%	98.80%
Financing Receivable, Year One, Originated, Current Fiscal Year	$ 7,599.8	$ 5,526.1
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	3,573.0	4,057.2
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	2,418.6	2,297.7
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	1,203.9	1,208.3
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	482.4	485.5
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	112.3	107.9
Credit Grade A [Member] | Core managed receivables
Financing Receivable, By Major Credit Grade [Line Items]
Total ending managed receivables	$ 7,749.7	$ 6,874.1
Total ending managed receivables as percentage by major credit grade	49.50%	49.60%
Financing Receivable, Year One, Originated, Current Fiscal Year	$ 3,885.5	$ 2,782.0
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	1,788.3	2,146.5
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	1,266.1	1,146.7
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	574.1	568.9
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	203.4	199.6
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	32.3	30.4
Credit Grade B | Core managed receivables
Financing Receivable, By Major Credit Grade [Line Items]
Total ending managed receivables	$ 5,670.1	$ 5,008.9
Total ending managed receivables as percentage by major credit grade	36.20%	36.20%
Financing Receivable, Year One, Originated, Current Fiscal Year	$ 2,795.2	$ 1,993.6
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	1,288.5	1,424.5
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	857.7	870.1
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	473.1	476.0
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	205.2	195.5
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	50.4	49.2
Credit Grade C And Other | Core managed receivables
Financing Receivable, By Major Credit Grade [Line Items]
Total ending managed receivables	$ 1,970.2	$ 1,799.7
Total ending managed receivables as percentage by major credit grade	12.60%	13.00%
Financing Receivable, Year One, Originated, Current Fiscal Year	$ 919.1	$ 750.5
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	496.2	486.2
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	294.8	280.9
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	156.7	163.4
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	73.8	90.4
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	29.6	28.3
Credit Grade C And Other | Other managed receivables
Financing Receivable, By Major Credit Grade [Line Items]
Total ending managed receivables	$ 262.3	$ 164.5
Total ending managed receivables as percentage by major credit grade	1.70%	1.20%
Financing Receivable, Year One, Originated, Current Fiscal Year	$ 165.2	$ 35.6
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	23.9	55.4
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	34.7	39.5
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	23.8	18.6
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	10.0	9.4
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	$ 4.7	$ 6.0