Disposal Group, Master Lease, Decrease In Annual Rent Payment

No definition available.

Name:	mgm_DisposalGroupMasterLeaseDecreaseInAnnualRentPayment
Namespace Prefix:	mgm_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Master Lease, Fixed Annual Rent Escalator Percentage

+ References

No definition available.

+ Details

Name:	mgm_MasterLeaseFixedAnnualRentEscalatorPercentage
Namespace Prefix:	mgm_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Number Of Integrated Casino, Hotel and Entertainment Resorts

+ References

No definition available.

+ Details

Name:	mgm_NumberOfIntegratedCasinoHotelAndEntertainmentResorts
Namespace Prefix:	mgm_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Organization disclosure.

+ References

No definition available.

+ Details

Name:	mgm_OrganizationDisclosureLineItems
Namespace Prefix:	mgm_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 825
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 28
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482907/825-10-50-28

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 323
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481687/323-10-50-3

+ Details

Name:	us-gaap_EquityMethodInvestmentOwnershipPercentage
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 47
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482785/280-10-55-47

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 54
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482785/280-10-55-54

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 18
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-18

+ Details

Name:	us-gaap_NumberOfReportableSegments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

The cash inflow associated with the amount received from the sale of a portion of the company's business, for example a segment, division, branch or other business, during the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-12

+ Details

Name:	us-gaap_ProceedsFromDivestitureOfBusinesses
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Percentage of subsidiary's or equity investee's stock owned by parent company after stock transaction.

+ References

No definition available.

+ Details

Name:	us-gaap_SaleOfStockPercentageOfOwnershipAfterTransaction
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementScenarioAxis=srt_ScenarioForecastMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=mgm_MGMNorthfieldParkMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=mgm_BetMGMNorthAmericaVentureMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_OtherOwnershipInterestsByNameAxis=mgm_EntainPLCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=mgm_MGMOsakaCorporationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementGeographicalAxis=country_JP
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_OwnershipAxis=mgm_MGMChinaHoldingsLimitedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

ORGANIZATION (Details) $ in Millions	6 Months Ended	9 Months Ended
ORGANIZATION (Details) $ in Millions	Jun. 30, 2026 USD ($)	Sep. 30, 2025 segment resort	May 01, 2026
Organization Disclosure [Line Items]
Number of reportable segments \| segment		4
Subsequent Event \| Forecast
Organization Disclosure [Line Items]
Rent escalator percentage			2.00%
Subsequent Event \| MGM Northfield Park \| Forecast
Organization Disclosure [Line Items]
Cash consideration	$ 546
Decrease in annual rent payment under master lease	$ 53
BetMGM North America Venture
Organization Disclosure [Line Items]
Ownership interest (as a percent)		50.00%
BetMGM North America Venture \| Entain plc
Organization Disclosure [Line Items]
Ownership interest (as a percent)		50.00%
MGM Osaka \| Japan
Organization Disclosure [Line Items]
Ownership interest (as a percent)		50.00%
MGM China
Organization Disclosure [Line Items]
Controlling interest (as a percent)		56.00%
Number of integrated casino \| resort		2