Description of Business and Summary of Significant Accounting Policies (Details 6) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	May 31, 2016	May 31, 2015	May 31, 2014
Treasury Shares [Abstract]
Stock Repurchase Program, Number Of Shares Authorized To Be Repurchased	25,000,000
Purchase of treasury stock	$ 2,722	$ 1,254	$ 4,857
Treasury Stock Acquired, Average Cost Per Share	$ 149.35	$ 154.03	$ 131.83
Purchase of treasury stock	18,200,000	8,100,000	36,800,000
Stock Repurchase Program, Remaining Number of Shares Authorized to be Repurchased	19,000,000
Stock Repurchase Program Number Of Shares Authorized To Be Repurchased Under the Previously Completed Program	15,000,000