CASH, CASH EQUIVALENTS AND MARKETABLE SECURITIES (Details) - USD ($) $ in Millions	12 Months Ended
	May. 31, 2015	May. 31, 2014
Cash, Cash Equivalents and Marketable Securities [Abstract]
U.S. Treasury securities	$ 668
Commercial paper debt securities	9,203	$ 7,969
Corporate debt securities and other	28,844	16,657
Total investments	38,715	24,626
Investments classified as cash equivalents	6,063	3,576
Investments classified as marketable securities	$ 32,652	$ 21,050
Maturity of marketable security investments	As of May 31, 2015 and 2014, approximately 28% and 45%, respectively, of our marketable securities investments mature within one year and 72% and 55%, respectively, mature within one to six years.