Stock and Stock-Based Incentive Plans Stock and Stock-Based Incentive Plans (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
	Aug. 31, 2016	May 31, 2016	Nov. 30, 2017	Nov. 30, 2016
Stock and Stock-Based Incentive Plans
Share-based Compensation Arrangement by Share-based Payment Award, Plan Modification, Incremental Compensation Cost	$ 10.9	$ 3.5
Share Repurchase Program
Stock and Stock-Based Incentive Plans
Stock Repurchase Program, Authorized Amount			$ 4,550.0
Available for repurchase, as of end of period			$ 1,144.6	$ 1,691.5