DERIVATIVE FINANCIAL INSTRUMENTS Narrative (Details) € in Millions, $ in Millions	3 Months Ended
	Aug. 31, 2016 USD ($)	Aug. 31, 2015 USD ($)	Jul. 07, 2016 USD ($)	May 31, 2016 USD ($)	Jul. 08, 2014 USD ($)	Jul. 16, 2013 USD ($)	Jul. 10, 2013 EUR (€)
Debt Instruments [Abstract]
Total debt issued			$ 14,000
Interest Rate Swap Agreements (Narrative) [Abstract]
Description of fair value hedges	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 $2.0 billion of 2.25% senior notes due October 2019 (October 2019 Notes) and our $1.5 billion of 2.80% senior notes due July 2021 (July 2021 Notes) so that the interest payable on these senior notes effectively became variable based on LIBOR. In July 2013, we entered into certain interest rate swap agreements that have the economic effect of modifying the fixed-interest obligations associated with our $1.5 billion of 2.375% senior notes due January 2019 (January 2019 Notes) so that the interest payable on these senior notes effectively became variable based on LIBOR. The critical terms of the interest rate swap agreements match the critical terms of the October 2019 Notes, July 2021 Notes and the January 2019 Notes that the interest rate swap agreements pertain to, including the notional amounts and maturity dates. We do not use any interest rate swap agreements for trading purposes.
Cash Flow Hedges (Narrative) [Abstract]
Description of cash flow hedges	In connection with the issuance of our €1.25 billion of 2.25% senior notes due January 2021 (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. We do not use any cross-currency swap agreements for trading purposes.
Net Investment Hedges (Narrative) [Abstract]
Description of net investment hedge	In July 2013, we designated our €750 million of 3.125% senior notes due July 2025 (July 2025 Notes) as a net investment hedge of our investments in certain of our international subsidiaries that use the Euro as their functional currency in order to reduce the volatility in stockholders’ equity caused by the changes in foreign currency exchange rates of the Euro with respect to the U.S. Dollar.
Foreign Currency Forward Contracts Not Designated as Hedges (Narrative) [Abstract]
Net gains related to forward contracts	$ 6	$ 97
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. We neither use these foreign currency forward contracts for trading purposes nor do we designate these forward contracts as hedging instruments pursuant to ASC 815 (refer to Note 11 of Notes to Consolidated Financial Statements as included in our Annual Report on Form 10-K for the fiscal year ended May 31, 2016 for additional information regarding these contracts). As of August 31, 2016 and May 31, 2016, the notional amounts of the forward contracts we held to purchase U.S. Dollars in exchange for other major international currencies were $2.1 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 $904 million and $2.0 billion, respectively. The fair values of our outstanding foreign currency forward contracts were nominal as of August 31, 2016 and May 31, 2016.
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	$ 2,100			$ 2,700
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	$ 904			$ 2,000
Fair value hedges [Member] | Interest rate swap agreements [Member] | 2.25% senior notes due October 2019 [Member]
Debt Instruments [Abstract]
Total debt issued					$ 2,000
Stated interest rate percentage	2.25%
Maturity date	Oct. 08, 2019
Fair value hedges [Member] | Interest rate swap agreements [Member] | 2.80% senior notes due July 2021 [Member]
Debt Instruments [Abstract]
Total debt issued					$ 1,500
Stated interest rate percentage	2.80%
Maturity date	Jul. 08, 2021
Fair value hedges [Member] | Interest rate swap agreements [Member] | 2.375% senior notes due January 2019 [Member]
Debt Instruments [Abstract]
Total debt issued						$ 1,500
Stated interest rate percentage	2.375%
Maturity date	Jan. 15, 2019
Cash flow hedges [Member] | Cross-currency swap agreements [Member]
Derivative Instrument Detail [Abstract]
Amount of ineffectiveness measured	$ 0	0
Cash flow hedges [Member] | Cross-currency swap agreements [Member] | 2.25% senior notes due January 2021 [Member]
Debt Instruments [Abstract]
Total debt issued | €							€ 1,250
Stated interest rate percentage	2.25%
Maturity date	Jan. 10, 2021
Senior notes fixed principal amount	$ 1,600
Annual interest rate for the 2.25% notes due January 2021 after the economic effect of the cross-currency swaps	3.53%
Net investment hedge [Member] | Foreign currency borrowings [Member]
Derivative Instrument Detail [Abstract]
Amount of ineffectiveness measured	$ 0	$ 0
Net investment hedge [Member] | Foreign currency borrowings [Member] | 3.125% senior notes due July 2025 [Member]
Debt Instruments [Abstract]
Total debt issued | €							€ 750
Stated interest rate percentage	3.125%
Maturity date	Jul. 10, 2025