Fair Value Measurements - Short-Term Investments Classified as Available-For-Sale (Detail) (USD $) In Millions, unless otherwise specified	Aug. 31, 2013	May 31, 2013
Available-for-sale investments:
Available-for-sale investments	$ 2,642	$ 2,628
U.S. Treasury and Agencies
Available-for-sale investments:
Available-for-sale investments	1,697	1,984
Corporate commercial paper and bonds
Available-for-sale investments:
Available-for-sale investments	$ 945	$ 644

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.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

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Reference 3: http://www.xbrl.org/2003/role/presentationRef

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Reference 4: http://www.xbrl.org/2003/role/presentationRef

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Reference 6: http://www.xbrl.org/2003/role/presentationRef

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Reference 8: http://www.xbrl.org/2003/role/presentationRef

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-Name Statement of Financial Accounting Standard (FAS)

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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