Stock and Stock-Based Incentive Plans Stock and Stock-Based Incentive Plans (Schedule of Common Stock Repurchases) (Details) - Share Repurchase Program - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Nov. 30, 2017	Nov. 30, 2016	Nov. 30, 2017	Nov. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Treasury Stock, Shares, Acquired	1,488,400	3,780,500	6,976,200	8,715,200
Treasury Stock Acquired, Average Cost Per Share	$ 72.02	$ 52.56	$ 63.90	$ 52.38
Available for repurchase, as of end of period	$ 1,144.6	$ 1,691.5	$ 1,144.6	$ 1,691.5