FAIR VALUE MEASUREMENTS Narrative (Details) - USD ($) $ in Billions	3 Months Ended
Aug. 31, 2018	May 31, 2018
Marketable security investments maturity information [Abstract]
Maturity of marketable security investments	As of August 31, 2018 and May 31, 2018, approximately 23% and 26%, respectively, of our marketable securities investments mature within one year and 77% and 74%, respectively, mature within one to five years.
Percentage of marketable securities investments mature within one year	23.00%	26.00%
Percentage of marketable securities investments mature within one to five years	77.00%	74.00%
Senior notes [Member]
Marketable security investments maturity information [Abstract]
Total debt, carrying value	$ 58.0	$ 58.0
Fair Value Measurements Using Input Types Level 2 [Member] \| Senior notes [Member]
Marketable security investments maturity information [Abstract]
Total debt, fair value	$ 58.7	$ 59.0

Maturity of marketable security investments

No definition available.

Name:	orcl_MaturityOfMarketableSecurityInvestments
Namespace Prefix:	orcl_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of marketable securities investments mature within one to five years.

+ References

No definition available.

+ Details

Name:	orcl_PercentageOfMarketableSecuritiesInvestmentsMatureWithinOneToFiveYears
Namespace Prefix:	orcl_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of marketable securities investments mature within one year.

+ References

No definition available.

+ Details

Name:	orcl_PercentageOfMarketableSecuritiesInvestmentsMatureWithinOneYear
Namespace Prefix:	orcl_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- References

No definition available.

+ Details

Name:	us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=109500613&loc=SL6031897-161870

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

Name:	us-gaap_DebtInstrumentCarryingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=109250915&loc=d3e13433-108611

+ Details

Name:	us-gaap_DebtInstrumentFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_SeniorNotesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: