EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended		6 Months Ended
		Nov. 30, 2019	Nov. 30, 2018	Nov. 30, 2019	Nov. 30, 2018
Earnings Per Share [Abstract]
Net income		$ 2,311	$ 2,333	$ 4,448	$ 4,598
Weighted average common shares outstanding		3,245	3,720	3,281	3,812
Dilutive effect of employee stock plans		86	97	89	96
Dilutive weighted average common shares outstanding		3,331	3,817	3,370	3,908
Basic earnings per share		$ 0.71	$ 0.63	$ 1.36	$ 1.21
Diluted earnings per share		$ 0.69	$ 0.61	$ 1.32	$ 1.18
Shares subject to anti-dilutive restricted stock-based awards and stock options excluded from calculation	[1]	55	72	55	76

[1] These weighted shares relate to anti-dilutive restricted service based stock‑based awards and stock options as calculated using the treasury stock method and contingently issuable shares under performance‑based stock option (PSO) and performance‑based restricted stock unit award (PSU) arrangements. Such shares could be dilutive in the future.