Auto Loan Receivables (Past Due Receivables) (Details) - USD ($) $ in Millions	Nov. 30, 2017	Feb. 28, 2017
Financing Receivable, Past Due [Line Items]
Total ending managed receivables	$ 11,455.6	$ 10,681.3
Total past due	$ 405.5	$ 331.0
Past due receivables as a percentage of total ending managed receivables	3.50%	3.10%
Total ending managed receivables, percent
Financing Receivable, Past Due [Line Items]
Item as percent of total ending managed receivables	100.00%	100.00%
Thirty One To Sixty Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total past due	$ 258.6	$ 211.0
Past due receivables as a percentage of total ending managed receivables	2.20%	2.00%
Sixty One To Ninety Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total past due	$ 116.3	$ 93.5
Past due receivables as a percentage of total ending managed receivables	1.00%	0.90%
Greater Than Ninety Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total past due	$ 30.6	$ 26.5
Past due receivables as a percentage of total ending managed receivables	0.30%	0.20%