Earnings Per Share - Reconciliation from Basic Earnings Per Share to Diluted Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	May 31, 2020	May 31, 2019	May 31, 2018
Earnings Per Share [Abstract]
Net income available to common stockholders	$ 2,539	$ 4,029	$ 1,933
Determination of shares:
Weighted average common shares outstanding	1,558.8	1,579.7	1,623.8
Assumed conversion of dilutive stock options and awards	32.8	38.7	35.3
DILUTED WEIGHTED AVERAGE COMMON SHARES OUTSTANDING	1,591.6	1,618.4	1,659.1
Earnings per common share:
Basic (in dollars per share)	$ 1.63	$ 2.55	$ 1.19
Diluted (in dollars per share)	$ 1.60	$ 2.49	$ 1.17