EARNINGS PER SHARE (Details) (USD $)
In Millions, except Per Share data, unless otherwise specified
 3 Months Ended 6 Months Ended
Nov. 30, 2012
Nov. 30, 2011
Nov. 30, 2012
Nov. 30, 2011
Computation of Basic and Diluted Earnings Per Share [Abstract]        
Net income $ 2,581 $ 2,192 $ 4,615 $ 4,032
Weighted average common shares outstanding 4,792 5,041 4,829 5,052
Dilutive effect of employee stock plans 76 82 75 85
Dilutive weighted average common shares outstanding 4,868 5,123 4,904 5,137
Basic earnings per share $ 0.54 $ 0.43 $ 0.96 $ 0.80
Diluted earnings per share $ 0.53 $ 0.43 $ 0.94 $ 0.78
Shares subject to anti-dilutive stock options and restricted stock-based awards excluded from calculation 223 [1] 117 [1] 206 [1] 101 [1]
[1] These weighted shares relate to anti-dilutive stock options and restricted stock-based awards as calculated using the treasury stock method (described above) and could be dilutive in the future.