EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended		6 Months Ended
		Nov. 30, 2020	Nov. 30, 2019	Nov. 30, 2020	Nov. 30, 2019
Earnings Per Share [Abstract]
Net income		$ 2,442	$ 2,311	$ 4,693	$ 4,448
Weighted average common shares outstanding		2,977	3,245	3,009	3,281
Dilutive effect of employee stock plans		69	86	67	89
Dilutive weighted average common shares outstanding		3,046	3,331	3,076	3,370
Basic earnings per share		$ 0.82	$ 0.71	$ 1.56	$ 1.36
Diluted earnings per share		$ 0.80	$ 0.69	$ 1.53	$ 1.32
Shares subject to anti-dilutive restricted stock-based awards and stock options excluded from calculation	[1]	36	55	36	55

[1] These weighted shares relate to anti-dilutive restricted stock-based awards and stock options, both of which were service-based, as calculated using the treasury stock method and contingently issuable shares, substantially all of which were related to performance based stock option (PSO) arrangements. Such shares could be dilutive in the future.