EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended		9 Months Ended
		Feb. 28, 2017	Feb. 29, 2016	Feb. 28, 2017	Feb. 29, 2016
Earnings Per Share [Abstract]
Net income		$ 2,239	$ 2,142	$ 6,103	$ 6,087
Weighted average common shares outstanding		4,107	4,182	4,110	4,246
Dilutive effect of employee stock plans		97	74	97	82
Dilutive weighted average common shares outstanding		4,204	4,256	4,207	4,328
Basic earnings per share		$ 0.55	$ 0.51	$ 1.49	$ 1.43
Diluted earnings per share		$ 0.53	$ 0.50	$ 1.45	$ 1.41
Shares subject to anti-dilutive restricted stock-based awards and stock options excluded from calculation	[1]	76	67	75	62

[1] These weighted shares relate to anti-dilutive restricted stock-based awards and stock options as calculated using the treasury stock method and could be dilutive in the future.