EARNINGS (LOSS) PER SHARE (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended		9 Months Ended
		Feb. 28, 2018	Feb. 28, 2017	Feb. 28, 2018	Feb. 28, 2017
Earnings Per Share [Abstract]
Net income (loss)		$ (4,024)	$ 2,239	$ 418	$ 6,103
Weighted average common shares outstanding		4,122	4,107	4,146	4,110
Dilutive effect of employee stock plans		0	97	122	97
Dilutive weighted average common shares outstanding		4,122	4,204	4,268	4,207
Basic earnings (loss) per share		$ (0.98)	$ 0.55	$ 0.10	$ 1.49
Diluted earnings (loss) per share		$ (0.98)	$ 0.53	$ 0.10	$ 1.45
Shares subject to anti-dilutive restricted stock-based awards and stock options excluded from calculation	[1]	190	76	60	75

[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 PSO and PSU arrangements. Such shares could be dilutive in the future.