CASH, CASH EQUIVALENTS AND MARKETABLE SECURITIES (Details) - USD ($) $ in Millions	12 Months Ended
May 31, 2018	May 31, 2017
Cash Cash Equivalents And Short Term Investments [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
Total investments	52,449	49,973
Investments classified as cash equivalents	6,808	5,679
Investments classified as marketable securities	$ 45,641	$ 44,294
Percentage of marketable securities investments mature within one year	26.00%	32.00%
Percentage of marketable securities investments mature within one to five years	74.00%	68.00%
Maturity of marketable security investments	As of May 31, 2018 and 2017, approximately 26% and 32%, respectively, of our marketable securities investments mature within one year and 74% and 68%, respectively, mature within one to five years.
Restricted cash and cash equivalent item, description	Restricted cash that was included within cash and cash equivalents as presented within our consolidated balance sheets as of May 31, 2018 and 2017 and our consolidated statements of cash flows for the years ended May 31, 2018, 2017 and 2016 was nominal.

Maturity of marketable security investments

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Percentage of marketable securities investments mature within one to five years.

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Percentage of marketable securities investments mature within one year.

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Amount of investment in debt and equity securities categorized neither as trading securities nor held-to-maturity securities and intended be sold or mature one year or operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
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Amount of short-term, 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. Excludes cash and cash equivalents within disposal group and discontinued operation.

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

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Sum of the carrying amounts as of the balance sheet date of all investments.

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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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Description of nature and provision of restriction as to withdrawal or usage on cash and cash equivalents.

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