FAIR VALUE MEASUREMENTS (Details) (USD $) In Millions, unless otherwise specified	Nov. 30, 2012	May 31, 2012
Assets [Abstract]
U.S. Treasury, U.S. government and U.S. government agency debt securities	$ 350	$ 100
Commercial paper debt securities	16,620	13,954
Corporate debt securities and other	4,605	2,237
Derivative financial instruments	57	69
Total assets	21,632	16,360
Liabilities [Abstract]
Contingent consideration	258	387
Total debt	19,800	16,500
Fair Value Measurements Using Input Types Level 1 [Member]
Assets [Abstract]
U.S. Treasury, U.S. government and U.S. government agency debt securities	350	100
Corporate debt securities and other	300	254
Total assets	650	354
Fair Value Measurements Using Input Types Level 2 [Member]
Assets [Abstract]
Commercial paper debt securities	16,620	13,954
Corporate debt securities and other	4,305	1,983
Derivative financial instruments	57	69
Total assets	20,982	16,006
Liabilities [Abstract]
Total debt fair value	22,800	19,300
Fair Value Measurements Using Input Types Level 3 [Member]
Liabilities [Abstract]
Contingent consideration	$ 258	$ 387