INCOME TAXES (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Feb. 29, 2020	Feb. 28, 2019	Feb. 29, 2020	Feb. 28, 2019	May 31, 2019
Income Tax Disclosure [Abstract]
Effective income tax rate	16.40%	11.10%	16.10%	12.60%
Income tax net benefit, adjustments to estimate of U.S. Tax Cuts and Jobs Act of 2017 one-time transition tax and remeasurement of net deferred tax assets and liabilities		$ 236		$ 389
Deferred Tax Assets, Net [Abstract]
Net deferred tax assets	$ 2,800		$ 2,800		$ 2,400