Auto Loan Receivables (Ending Managed Receivables By Major Credit Grade) (Details) - USD ($) $ in Millions	Feb. 28, 2023	Feb. 28, 2022
Financing Receivable, By Major Credit Grade [Line Items]
Total ending managed receivables	$ 16,767.9	$ 15,652.3
Total ending managed receivables as percentage by major credit grade	100.00%	100.00%
Financing Receivable, Year One, Originated, Current Fiscal Year	$ 7,393.1	$ 7,765.0
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	5,117.2	3,596.9
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	2,257.7	2,453.3
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	1,356.4	1,227.7
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	520.7	492.4
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	122.8	117.0
Core managed receivables
Financing Receivable, By Major Credit Grade [Line Items]
Total ending managed receivables	$ 16,329.2	$ 15,390.0
Total ending managed receivables as percentage by major credit grade	97.40%	98.30%
Financing Receivable, Year One, Originated, Current Fiscal Year	$ 7,121.1	$ 7,599.8
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	5,004.7	3,573.0
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	2,242.7	2,418.6
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	1,335.3	1,203.9
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	507.5	482.4
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	117.9	112.3
Credit Grade A [Member] | Core managed receivables
Financing Receivable, By Major Credit Grade [Line Items]
Total ending managed receivables	$ 8,489.9	$ 7,749.7
Total ending managed receivables as percentage by major credit grade	50.60%	49.50%
Financing Receivable, Year One, Originated, Current Fiscal Year	$ 3,890.9	$ 3,885.5
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	2,555.3	1,788.3
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	1,112.0	1,266.1
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	677.1	574.1
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	218.3	203.4
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	36.3	32.3
Credit Grade B | Core managed receivables
Financing Receivable, By Major Credit Grade [Line Items]
Total ending managed receivables	$ 5,913.6	$ 5,670.1
Total ending managed receivables as percentage by major credit grade	35.30%	36.20%
Financing Receivable, Year One, Originated, Current Fiscal Year	$ 2,497.5	$ 2,795.2
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	1,839.9	1,288.5
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	816.2	857.7
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	488.9	473.1
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	215.1	205.2
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	56.0	50.4
Credit Grade C And Other | Core managed receivables
Financing Receivable, By Major Credit Grade [Line Items]
Total ending managed receivables	$ 1,925.7	$ 1,970.2
Total ending managed receivables as percentage by major credit grade	11.50%	12.60%
Financing Receivable, Year One, Originated, Current Fiscal Year	$ 732.7	$ 919.1
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	609.5	496.2
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	314.5	294.8
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	169.3	156.7
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	74.1	73.8
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	25.6	29.6
Credit Grade C And Other | Other managed receivables
Financing Receivable, By Major Credit Grade [Line Items]
Total ending managed receivables	$ 438.7	$ 262.3
Total ending managed receivables as percentage by major credit grade	2.60%	1.70%
Financing Receivable, Year One, Originated, Current Fiscal Year	$ 272.0	$ 165.2
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	112.5	23.9
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	15.0	34.7
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	21.1	23.8
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	13.2	10.0
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	$ 4.9	$ 4.7