INCOME TAXES Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	May 31, 2017	May 31, 2016	May 31, 2015
Deferred Tax Assets and Liabilities (Narrative) [Abstract]
Temporary differences related to undistributed foreign earnings	$ 47,500
Other outside basis temporary differences of investments in foreign subsidiaries	7,900
Potential net deferred tax liability associated with these undistributed foreign earnings	15,100
Potential net deferred tax liability related to other outside basis temporary differences	2,600
Net deferred tax assets	683	$ 1,131
Valuation allowance	1,164	1,173
Tax Credit Carryforwards [Abstract]
Tax credit carryforwards subject to limitation on utilization	1,800
Tax credit carryforwards not subject to expiration dates	696
Tax credit carryforwards subject to expiration dates	1,100
Unrecognized Tax Benefits (Narrative) [Abstract]
Unrecognized tax benefits that would affect our effective tax rate if recognized	3,400	3,100	$ 2,800
Interest and penalties related to uncertain tax positions recognized in our provision for income taxes	125	26	$ 102
Interest and penalties related to uncertain tax positions accrued	$ 885	$ 765
Income Tax Examinations [Abstract]
Income tax examinations	We are under audit by the IRS and various other domestic and foreign tax authorities with regards to income tax and indirect tax matters and are involved in various challenges and litigation in a number of countries, including, in particular, Australia, Brazil, India, Korea, Spain and the United Kingdom, where the amounts under controversy are significant. In some, although not all, cases, we have reserved for potential adjustments to our provision for income taxes and accrual of indirect taxes that may result from examinations by, or any negotiated agreements with, these tax authorities or final outcomes in judicial proceedings, and we believe that the final outcome of these examinations, agreements or judicial proceedings will not have a material effect on our results of operations. If events occur which indicate payment of these amounts is unnecessary, the reversal of the liabilities would result in the recognition of benefits in the period we determine the liabilities are no longer necessary. If our estimates of the federal, state, and foreign income tax liabilities and indirect tax liabilities are less than the ultimate assessment, it could result in a further charge to expense.
Earliest Tax Year [Member]
Tax Credit Carryforwards [Abstract]
Tax credit carryforward expiration dates	May 31, 2018
Latest Tax Year [Member]
Tax Credit Carryforwards [Abstract]
Tax credit carryforward expiration dates	May 31, 2038
Federal [Member]
Operating Loss Carryforwards [Abstract]
Net operating loss carryforwards	$ 1,600
Federal [Member] | Earliest Tax Year [Member]
Operating Loss Carryforwards [Abstract]
Operating loss carryforwards expiration date	May 31, 2018
Federal [Member] | Latest Tax Year [Member]
Operating Loss Carryforwards [Abstract]
Operating loss carryforwards expiration date	May 31, 2036
State [Member]
Operating Loss Carryforwards [Abstract]
Net operating loss carryforwards	$ 2,400
State [Member] | Earliest Tax Year [Member]
Operating Loss Carryforwards [Abstract]
Operating loss carryforwards expiration date	May 31, 2018
State [Member] | Latest Tax Year [Member]
Operating Loss Carryforwards [Abstract]
Operating loss carryforwards expiration date	May 31, 2037
Foreign [Member]
Operating Loss Carryforwards [Abstract]
Net operating loss carryforwards	$ 1,900
Foreign net operating loss carryforwards not subject to expiration	1,700
Foreign net operating loss carryforwards subject to expiration	187
Unrecognized Tax Benefits (Narrative) [Abstract]
Reasonably possible decrease in the next 12 months in gross unrecognized, net of offsetting tax benefits	78
Reasonably possible decrease in the next 12 months in gross unrecognized tax benefits	$ 152
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. We believe that it was reasonably possible that, as of May 31, 2017, the gross unrecognized tax benefits, could decrease (whether by payment, release, or a combination of both) by as much as $152 million ($78 million net of offsetting tax benefits) in the next 12 months, related primarily to transfer pricing. With some exceptions, we are generally no longer subject to tax examinations in non-U.S. jurisdictions for years prior to fiscal 1997.
Foreign [Member] | Earliest Tax Year [Member]
Operating Loss Carryforwards [Abstract]
Operating loss carryforwards expiration date	May 31, 2018
Foreign [Member] | Latest Tax Year [Member]
Operating Loss Carryforwards [Abstract]
Operating loss carryforwards expiration date	May 31, 2037
Domestic [Member]
Unrecognized Tax Benefits (Narrative) [Abstract]
Reasonably possible decrease in the next 12 months in gross unrecognized, net of offsetting tax benefits	$ 336
Reasonably possible decrease in the next 12 months in gross unrecognized tax benefits	$ 389
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 2016. Many issues are at an advanced stage in the examination process, the most significant of which include the deductibility of certain royalty payments, transfer pricing, extraterritorial income exemptions, domestic production activity, foreign tax credits, and research and development credits taken. With all of these domestic audit issues considered in the aggregate, we believe that it was reasonably possible that, as of May 31, 2017, the gross unrecognized tax benefits related to these audits could decrease (whether by payment, release, or a combination of both) in the next 12 months by as much as $389 million ($336 million net of offsetting tax benefits). 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.