DERIVATIVE FINANCIAL INSTRUMENTS Narrative (Details) - USD ($) $ in Billions	12 Months Ended
	May 31, 2019	May 31, 2018
Interest Rate Swap Agreements and Cross-Currency Interest Rate Swap Agreements (Narrative) [Abstract]
Description of fair value hedges	In May 2018, we entered into certain cross-currency interest rate swap agreements to manage the foreign currency exchange rate risk associated with our July 2025 Notes by effectively converting the fixed-rate, Euro denominated 2025 Notes, including the annual interest payments and the payment of principal at maturity, to variable-rate, U.S. Dollar denominated debt based on LIBOR. In July 2014, we entered into certain interest rate swap agreements that have the economic effect of modifying the fixed-interest obligations associated with our October 2019 Notes and our July 2021 Notes so that the interest payable on these senior notes effectively became variable based on LIBOR. The critical terms of the swap agreements match the critical terms of the July 2025 Notes, October 2019 Notes, and July 2021 Notes that the swap agreements pertain to, including the notional amounts and maturity dates.
Cash Flow Hedges (Narrative) [Abstract]
Description of cash flow hedges	In connection with the issuance of the January 2021 Notes, we entered into certain cross-currency swap agreements to manage the related foreign currency exchange risk by effectively converting the fixed-rate, Euro-denominated January 2021 Notes, including the annual interest payments and the payment of principal at maturity, to fixed-rate, U.S. Dollar-denominated debt. The economic effect of the swap agreements was to eliminate the uncertainty of the cash flows in U.S. Dollars associated with the January 2021 Notes by fixing the principal amount of the January 2021 Notes at $1.6 billion with a fixed annual interest rate of 3.53%. We have designated these cross-currency swap agreements as qualifying hedging instruments and are accounting for these as cash flow hedges pursuant to ASC 815. The critical terms of the cross-currency swap agreements correspond to the January 2021 Notes including the annual interest payments being hedged, and the cross-currency swap agreements mature at the same time as the January 2021 Notes.
Foreign Currency Forward Contracts Not Designated as Hedges [Abstract]
Description of foreign currency forward contracts not designated as hedges	We transact business in various foreign currencies and have established a program that primarily utilizes foreign currency forward contracts to offset the risks associated with the effects of certain foreign currency exposures. Under this program, our strategy is to enter into foreign currency forward contracts so that increases or decreases in our foreign currency exposures are offset by gains or losses on the foreign currency forward contracts in order to mitigate the risks and volatility associated with our foreign currency transactions. We may suspend this program from time to time. Our foreign currency exposures typically arise from intercompany sublicense fees, intercompany loans and other intercompany transactions that are generally expected to be cash settled in the near term. Neither do we use these foreign currency forward contracts for trading purposes nor do we designate these forward contracts as hedging instruments pursuant to ASC 815. The fair values of our outstanding foreign currency forward contracts were nominal at May 31, 2019 and 2018.
Forward contracts held to purchase U.S. Dollars [Member] | Foreign Currency Forward Contracts Not Designated as Hedges [Member]
Foreign Currency Forward Contracts Not Designated as Hedges (Narrative) [Abstract]
Notional amounts of forward contracts	$ 3.8	$ 3.4
Forward contracts held to sell U.S. Dollars [Member] | Foreign Currency Forward Contracts Not Designated as Hedges [Member]
Foreign Currency Forward Contracts Not Designated as Hedges (Narrative) [Abstract]
Notional amounts of forward contracts	3.3	$ 1.4
Cash flow hedges [Member] | Cross-Currency Swap Agreements [Member]
Debt Instruments [Abstract]
Senior notes fixed principal amount	$ 1.6
Annual interest rate for the 2.25% notes due January 2021 after the economic effect of the cross-currency swaps	3.53%