Fair Value Measurements - Short-Term Investments Classified as Available-For-Sale (Detail) (USD $) In Millions, unless otherwise specified	May 31, 2013	May 31, 2012
Available-for-sale investments:
Available-for-sale investments	$ 2,628	$ 1,440
U.S. Treasury and Agencies
Available-for-sale investments:
Available-for-sale investments	1,984	1,157
Corporate commercial paper and bonds
Available-for-sale investments:
Available-for-sale investments	$ 644	$ 283

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

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