CONDENSED CONSOLIDATED BALANCE SHEETS PARENTHETICAL - USD ($) $ in Millions	Feb. 28, 2019	May 31, 2018
Statement Of Financial Position [Abstract]
Allowance for doubtful accounts receivable	$ 351	$ 370
Preferred stock par value per share	$ 0.01	$ 0.01
Preferred stock shares authorized	1,000,000	1,000,000
Preferred stock shares outstanding	0	0
Common stock par value per share	$ 0.01	$ 0.01
Common stock shares authorized	11,000,000,000	11,000,000,000
Common stock shares outstanding	3,443,000,000	3,997,000,000