Stock-Based Employee Compensation (Details 4) (USD $)	12 Months Ended
	Feb. 28, 2014	Feb. 28, 2013	Feb. 29, 2012
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Weighted average grant-date fair value of stock options granted	$ 16.88	$ 8.39	$ 7.41
Total fair value of stock options vested	$ 20,457,096	$ 22,421,290	$ 31,140,184
Total intrinsic value of stock options exercised	235,540,914	95,033,640	23,139,194
Tax benefit realized from stock options exercised	$ 61,354,379	$ 25,274,158	$ 10,835,473