FAIR VALUE MEASUREMENTS (Details) (USD $) In Millions, unless otherwise specified	Aug. 31, 2012	May 31, 2012
Assets [Abstract]
Money market funds	$ 25	$ 25
U.S. Treasury, U.S. government and U.S. government agency debt securities	100	100
Commercial paper debt securities	15,435	13,954
Corporate debt securities and other	3,066	2,212
Derivative financial instruments	65	69
Total assets	18,691	16,360
Liabilities [Abstract]
Contingent consideration	403	387
Total debt	14,800	16,500
Fair Value Measurements Using Input Types Level 1 [Member]
Assets [Abstract]
Money market funds	25	25
U.S. Treasury, U.S. government and U.S. government agency debt securities	100	100
Corporate debt securities and other	433	229
Total assets	558	354
Fair Value Measurements Using Input Types Level 2 [Member]
Assets [Abstract]
Commercial paper debt securities	15,435	13,954
Corporate debt securities and other	2,633	1,983
Derivative financial instruments	65	69
Total assets	18,133	16,006
Liabilities [Abstract]
Total debt fair value	17,800	19,300
Fair Value Measurements Using Input Types Level 3 [Member]
Liabilities [Abstract]
Contingent consideration	$ 403	$ 387