FAIR VALUE MEASUREMENTS (Details) - USD ($) $ in Millions	3 Months Ended
	Aug. 31, 2016	May 31, 2016
Assets [Abstract]
Money market funds	$ 4,251	$ 3,750
U.S. Treasury securities	14	214
Commercial paper debt securities	8,339	2,155
Corporate debt securities and other	36,822	35,274
Derivative financial instruments	131	122
Total assets	49,557	41,515
Liabilities [Abstract]
Derivative financial instruments	$ 215	$ 218
Marketable security investments maturity information [Abstract]
Maturity of marketable security investments	As of August 31, 2016 and May 31, 2016, approximately 37% and 28%, respectively, of our marketable securities investments mature within one year and 63% and 72%, respectively, mature within one to six years.
Percentage of marketable securities investments mature within one year	37.00%	28.00%
Percentage of marketable securities investments mature within one to six years	63.00%	72.00%
Short and Long Term Debt [Abstract]
Short-term borrowings	$ 999	$ 3,750
Senior notes	54,100	40,100
Fair Value Measurements Using Input Types Level 1 [Member]
Assets [Abstract]
Money market funds	4,251	3,750
U.S. Treasury securities	14	214
Corporate debt securities and other	166	179
Total assets	4,431	4,143
Fair Value Measurements Using Input Types Level 2 [Member]
Assets [Abstract]
Commercial paper debt securities	8,339	2,155
Corporate debt securities and other	36,656	35,095
Derivative financial instruments	131	122
Total assets	45,126	37,372
Liabilities [Abstract]
Derivative financial instruments	215	218
Total debt fair value	$ 58,100	$ 43,200