INCOME TAXES (Details) - USD ($) $ in Millions	3 Months Ended
	Aug. 31, 2017	Aug. 31, 2016	May 31, 2017
Income Tax Examination [Line Items]
Effective income tax rate	14.50%	22.80%
Net deferred tax assets	$ 693		$ 683
Domestic Country [Member]
Income Tax Examination [Line Items]
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 2016. 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 Country [Member]
Income Tax Examination [Line Items]
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.