EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended		9 Months Ended
		Feb. 29, 2020	Feb. 28, 2019	Feb. 29, 2020	Feb. 28, 2019
Earnings Per Share [Abstract]
Net income		$ 2,571	$ 2,745	$ 7,019	$ 7,343
Weighted average common shares outstanding		3,190	3,526	3,251	3,716
Dilutive effect of employee stock plans		81	91	86	95
Dilutive weighted average common shares outstanding		3,271	3,617	3,337	3,811
Basic earnings per share		$ 0.81	$ 0.78	$ 2.16	$ 1.98
Diluted earnings per share		$ 0.79	$ 0.76	$ 2.10	$ 1.93
Shares subject to anti-dilutive restricted stock-based awards and stock options excluded from calculation	[1]	55	67	55	73

[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.