FAIR VALUE MEASUREMENTS (Details) - USD ($) $ in Millions	May 31, 2018	May 31, 2017
Assets [Abstract]
Corporate debt securities and other	$ 44,302	$ 41,618
Commercial paper debt securities	1,647	5,053
Money market funds	6,500	3,302
Derivative financial instruments	29	40
Total assets	52,478	50,013
Liabilities [Abstract]
Derivative financial instruments	158	191
Fair Value Measurements Using Input Types Level 1 [Member]
Assets [Abstract]
Corporate debt securities and other	223	580
Commercial paper debt securities	0	0
Money market funds	6,500	3,302
Derivative financial instruments	0	0
Total assets	6,723	3,882
Liabilities [Abstract]
Derivative financial instruments	0	0
Fair Value Measurements Using Input Types Level 2 [Member]
Assets [Abstract]
Corporate debt securities and other	44,079	41,038
Commercial paper debt securities	1,647	5,053
Money market funds	0	0
Derivative financial instruments	29	40
Total assets	45,755	46,131
Liabilities [Abstract]
Derivative financial instruments	$ 158	$ 191

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Unsecured short-term debt instrument issued by corporations which are highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three-years ago does not become a cash equivalent when its remaining maturity is three months.

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Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement.

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Fair value, before effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement.

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Fair value of firm holdings in corporate fixed income securities. Includes pledged and unpledged holdings.

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Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method.

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Investment in short-term money-market instruments (such as commercial paper, banker's acceptances, repurchase agreements, government securities, certificates of deposit, and so forth) which are highly liquid (that is, readily convertible to known amounts of cash) and so near their maturity that they present an insignificant risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify as cash equivalents by definition. Original maturity means an original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three-years ago does not become a cash equivalent when its remaining maturity is three months.

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