INCOME TAXES (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Feb. 28, 2019	Feb. 28, 2018	Feb. 28, 2019	Feb. 28, 2018	May 31, 2018
Income Tax Examination [Line Items]
Effective income tax rate	11.10%	226.80%	12.60%	96.40%
Federal statutory income tax rate, percent			21.00%
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			$ 389
Deferred Tax Assets, Net [Abstract]
Net deferred tax assets	$ 2,000		$ 2,000		$ 1,300
Domestic [Member]
Income Tax Examinations [Abstract]
Income tax examinations			Domestically, U.S. federal and state taxing authorities are currently examining income tax returns of Oracle and various acquired entities for years through fiscal 2017. Our U.S. federal income tax returns have been examined for all years prior to fiscal 2007, and we are no longer subject to audit for those periods. Our U.S. state income tax returns, with some exceptions, have been examined for all years prior to fiscal 2004, and we are no longer subject to audit for those periods.
Foreign [Member]
Income Tax Examinations [Abstract]
Income tax examinations			Internationally, tax authorities for numerous non-U.S. jurisdictions are also examining returns affecting our unrecognized tax benefits. With some exceptions, we are generally no longer subject to tax examinations in non-U.S. jurisdictions for years prior to fiscal 1997.