DERIVATIVE FINANCIAL INSTRUMENTS Narrative (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Feb. 28, 2017	Feb. 29, 2016	Feb. 28, 2017	Feb. 29, 2016	May 31, 2016
Foreign Currency Forward Contracts Not Designated as Hedges (Narrative) [Abstract]
Net gains (losses) related to forward contracts	$ (74)	$ 93	$ (53)	$ 163
Foreign Currency Forward Contracts Not Designated as Hedges [Abstract]
Description of foreign currency forward contracts not designated as hedges			We also held certain foreign currency contracts that were not designated as hedges pursuant to ASC 815. The notional amounts of such forward contracts we held to purchase U.S. Dollars in exchange for other major international currencies were $2.3 billion and $2.7 billion, respectively, and the notional amount of forward contracts we held to sell U.S. Dollars in exchange for other major international currencies were $2.0 billion and $2.0 billion, respectively. The fair values of our outstanding foreign currency forward contracts were nominal as of February 28, 2017 and May 31, 2016.
Foreign Currency Forward Contracts Not Designated as Hedges [Member] | Forward contracts held to purchase U.S. Dollars [Member]
Foreign Currency Forward Contracts Not Designated as Hedges (Narrative) [Abstract]
Notional amounts of forward contracts	2,300		$ 2,300		$ 2,700
Foreign Currency Forward Contracts Not Designated as Hedges [Member] | Forward contracts held to sell U.S. Dollars [Member]
Foreign Currency Forward Contracts Not Designated as Hedges (Narrative) [Abstract]
Notional amounts of forward contracts	$ 2,000		$ 2,000		$ 2,000