Basis of presentation and summary of significant accounting policies.

No definition available.

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

- Definition

Debt Instrument, Face Amount After Optional Increase

+ References

No definition available.

+ Details

Name:	mgm_DebtInstrumentFaceAmountAfterOptionalIncrease
Namespace Prefix:	mgm_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Disposal group including discontinued operation consideration notes receivable fair value.

+ References

No definition available.

+ Details

Name:	mgm_DisposalGroupIncludingDiscontinuedOperationConsiderationNotesReceivableFairValue
Namespace Prefix:	mgm_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Minority interest ownership percentage in unconsolidated affiliate.

+ References

No definition available.

+ Details

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

- Definition

Percentage of ownership interest.

+ References

No definition available.

+ Details

Name:	mgm_PercentageOfOwnershipInterest
Namespace Prefix:	mgm_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount charged to advertising expense for the period, which are expenses incurred with the objective of increasing revenue for a specified brand, product or product line.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 720
-SubTopic 35
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=6420018&loc=d3e36677-107848

+ Details

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

- Definition

Future cash outflow to pay for purchases of fixed assets that have occurred.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 5
-URI https://asc.fasb.org/extlink&oid=126999549&loc=d3e4332-108586

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 4
-URI https://asc.fasb.org/extlink&oid=126999549&loc=d3e4313-108586

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 3
-URI https://asc.fasb.org/extlink&oid=126999549&loc=d3e4304-108586

+ Details

Name:	us-gaap_CapitalExpendituresIncurredButNotYetPaid
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 42
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e9054-108599

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 18
-URI https://asc.fasb.org/extlink&oid=99393423&loc=d3e6351-108592

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 20
-URI https://asc.fasb.org/extlink&oid=123594938&loc=d3e13531-108611

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 21
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=123594938&loc=d3e13537-108611

Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 20
-URI https://asc.fasb.org/extlink&oid=99393423&loc=d3e6404-108592

+ Details

Name:	us-gaap_ConcentrationRiskPercentage1
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1B
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=123466505&loc=SL123495323-112611

Reference 2: 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(a)(1))
-URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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

- Definition

Amount of consideration received or receivable for the disposal of assets and liabilities, including discontinued operation.

+ References

No definition available.

+ Details

Name:	us-gaap_DisposalGroupIncludingDiscontinuedOperationConsideration
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 45
-Paragraph 1A
-URI https://asc.fasb.org/extlink&oid=123594786&loc=SL75136599-209740

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(2))
-URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_EquitySecuritiesFvNiCurrentAndNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of unrealized and realized gain (loss) on investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 321
-SubTopic 10
-Section 50
-Paragraph 4
-URI https://asc.fasb.org/extlink&oid=126980263&loc=SL75117546-209714

+ Details

Name:	us-gaap_EquitySecuritiesFvNiGainLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Total loss recognized during the period from the impairment of goodwill plus the loss recognized in the period resulting from the impairment of the carrying amount of intangible assets, other than goodwill.

+ References

No definition available.

+ Details

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

- Definition

Amount of investment in equity method investee and investment in and advance to affiliate.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(18))
-URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of lease income from operating, direct financing, and sales-type leases. Includes, but is not limited to, variable lease payments, interest income, profit (loss) recognized at commencement, and lease payments paid and payable to lessor.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 30
-Section 50
-Paragraph 5
-URI https://asc.fasb.org/extlink&oid=124258985&loc=SL77919372-209981

+ Details

Name:	us-gaap_LeaseIncome
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Yield on the receivable, on which interest has been imputed, as calculated from its issuance value or purchase price. The calculated effective interest rate considers factors such as the issued face value or price paid for the receivable, the time period between payments, and the time until maturity [full receipt] of the receivable.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI https://asc.fasb.org/extlink&oid=124435984&loc=d3e28551-108399

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 50
-Paragraph 1
-URI https://asc.fasb.org/extlink&oid=124429444&loc=SL124452920-239629

+ Details

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

- Definition

Percentage of the Variable Interest Entity's (VIE) voting interest owned by (or beneficial interest in) the reporting entity (directly or indirectly).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 5A
-Subparagraph (d)
-URI https://asc.fasb.org/extlink&oid=123419778&loc=SL6759159-111685

+ Details

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

- Details

Name:	us-gaap_IncomeStatementLocationAxis=mgm_FoodAndBeverageRevenueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeStatementLocationAxis=mgm_EntertainmentRetailAndOtherRevenueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BalanceSheetLocationAxis=us-gaap_OtherNoncurrentAssetsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=mgm_CircusCircusLasVegasAndAdjacentLandMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ConcentrationRiskByBenchmarkAxis=us-gaap_AccountsReceivableMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ConcentrationRiskByTypeAxis=us-gaap_CreditConcentrationRiskMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ProductOrServiceAxis=us-gaap_CasinoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=mgm_SecuredNoteDue2024InterestRateInFirstTwoYearsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=mgm_SecuredNoteDue2024InterestRateInFollowingTwoYearsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=mgm_SecuredNoteDue2024InterestRateInFifthYearMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=mgm_LeoVegasSeniorNotesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=mgm_BellagioBREITVentureMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=mgm_BellagioBlackstoneRealEstateIncomeTrustMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES - Additional Information (Detail) kr in Millions	1 Months Ended	12 Months Ended
	Dec. 31, 2019 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Sep. 30, 2022 SEK (kr)
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Investments in and advances to unconsolidated affiliates		$ 173,039,000	$ 967,044,000
Ownership interest (in percent)		100.00%
Fair value of equity investments		$ 461,000,000	66,000,000
Gain (loss) on equity investments		10,000,000	28,000,000
Impairment charges		0	0	$ 0
Accrual for property and equipment within accounts payable		80,000,000	59,000,000
Advertising expense		235,000,000	121,000,000	88,000,000
Food and Beverage Revenue
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Lease revenue		72,000,000	43,000,000	24,000,000
Entertainment Retail and Other Revenue
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Lease revenue		118,000,000	85,000,000	$ 60,000,000
Other Assets, Net
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Consideration receivable from sale of assets, notes receivable fair value		$ 167,000,000	$ 155,000,000
Circus Circus Las Vegas and Adjacent Land
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Consideration received from sale of real estate assets	$ 163,000,000
Consideration receivable from sale of assets, notes receivable fair value	$ 134,000,000
Secured note effective interest rate (in percent)	7.31%
Accounts Receivable \| Credit Concentration Risk \| Casino
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Gross casino accounts receivable (in percent)		52.00%	53.00%
Secured Note Due 2024 Interest Rate in First Two Years \| Circus Circus Las Vegas and Adjacent Land
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Long-term debt, interest rate (in percent)	3.00%
Secured Note Due 2024 Interest Rate in Following Two Years \| Circus Circus Las Vegas and Adjacent Land
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Long-term debt, interest rate (in percent)	4.00%
Secured Note Due 2024 Interest Rate in Fifth Year \| Circus Circus Las Vegas and Adjacent Land
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Long-term debt, interest rate (in percent)	4.50%
LeoVegas Senior Notes
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Face amount after optional increase \| kr					kr 800
Long-term debt, interest rate (in percent)		7.99%
Bellagio B R E I T Venture
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Minority interest (in percent)		5.00%
Bellagio B R E I T Venture \| Subsidiary Of Blackstone Real Estate Income Trust
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Ownership interest (in percent)		95.00%
Bellagio Blackstone Real Estate Income Trust
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Investments in and advances to unconsolidated affiliates		$ 56,000,000