Auto Loan Receivables (Ending Managed Receivables By Major Credit Grade) (Details) (USD $) In Millions, unless otherwise specified	Aug. 31, 2012		Feb. 29, 2012		Aug. 31, 2011		Feb. 28, 2011
Financing Receivable, By Major Credit Grade [Line Items]
Total ending managed receivables	$ 5,342.1	[1]	$ 4,981.8	[1]	$ 4,707.7	[1]	$ 4,334.6	[1]
Total ending managed receivables as percentage by major credit grade	100.00%	[2]	100.00%	[2]	100.00%	[2]	100.00%	[2]
Credit Grade A [Member]
Financing Receivable, By Major Credit Grade [Line Items]
Total ending managed receivables	2,548.5	[1]	2,452.8	[1]	2,385.9	[1]	2,234.1	[1]
Total ending managed receivables as percentage by major credit grade	47.70%	[2]	49.20%	[2]	50.70%	[2]	51.50%	[2]
Credit Grade B [Member]
Financing Receivable, By Major Credit Grade [Line Items]
Total ending managed receivables	2,088.9	[1]	1,923.6	[1]	1,838.3	[1]	1,668.0	[1]
Total ending managed receivables as percentage by major credit grade	39.10%	[2]	38.60%	[2]	39.00%	[2]	38.50%	[2]
Credit Grade C And Other [Member]
Financing Receivable, By Major Credit Grade [Line Items]
Total ending managed receivables	$ 704.7	[1]	$ 605.4	[1]	$ 483.5	[1]	$ 432.5	[1]
Total ending managed receivables as percentage by major credit grade	13.20%	[2]	12.20%	[2]	10.30%	[2]	10.00%	[2]

[1] Classified based on credit grade assigned when customers were initially approved for financing.

[2] Percent of total ending managed receivables.