CASH, CASH EQUIVALENTS AND MARKETABLE SECURITIES (Details) - USD ($) $ in Millions	12 Months Ended
	May 31, 2017	May 31, 2016
Cash Cash Equivalents And Short Term Investments [Abstract]
Corporate debt securities and other	$ 41,618	$ 35,488
Commercial paper debt securities	5,053	2,155
Money market funds	3,302	3,750
Total investments	49,973	41,393
Investments classified as cash equivalents	5,679	5,420
Investments classified as marketable securities	$ 44,294	$ 35,973
Percentage of marketable securities investments mature within one year	32.00%	28.00%
Percentage of marketable securities investments mature within one to five years	68.00%	72.00%
Maturity of marketable security investments	As of May 31, 2017 and 2016, approximately 32% and 28%, respectively, of our marketable securities investments mature within one year and 68% and 72%, respectively, mature within one to five years.
Restricted cash and cash equivalent item, description	Restricted cash that was included within cash and cash equivalents as presented within our consolidated balance sheets as of May 31, 2017 and May 31, 2016 and our consolidated statements of cash flows for the years ended May 31, 2017, May 31, 2016 and May 31, 2015 was nominal.