Debt instrument issued price percentage.

No definition available.

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Balance Type:	na
Period Type:	duration

- Definition

Debt instrument maturity year.

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Fair value of interest rate swaps designated as cash flow hedges recorded as current liability.

+ References

No definition available.

+ Details

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Namespace Prefix:	mgm_
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Period Type:	instant

- Definition

Fair value of interest rate swaps designated as cash flow hedges recorded as liability.

+ References

No definition available.

+ Details

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- Definition

Fair value of interest rate swaps designated as cash flow hedges recorded as long term liability.

+ References

No definition available.

+ Details

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- Definition

Fair value of interest rate swaps not designated as cash flow hedges recorded as current liability.

+ References

No definition available.

+ Details

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Namespace Prefix:	mgm_
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Period Type:	instant

- Definition

Fair value of interest rate swaps not designated as cash flow hedges recorded as liability.

+ References

No definition available.

+ Details

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Namespace Prefix:	mgm_
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- Definition

Fair value of interest rate swaps not designated as cash flow hedges recorded as long term liability.

+ References

No definition available.

+ Details

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Balance Type:	credit
Period Type:	instant

- Definition

Amount of cash eligible for distribution to members or limited partners of limited liability company (LLC) or limited partnership (LP), subject to reserves to be maintained as defined in operating or partnership agreement, or in a credit facility agreement.

+ References

No definition available.

+ Details

Name:	us-gaap_CashAvailableForDistributions
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- 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=120520924&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=120400017&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
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-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
-Topic 942
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-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Face (par) amount of debt instrument at time of issuance.

+ 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
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-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

+ Details

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

- Definition

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

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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

- Definition

Weighted average interest rate of debt outstanding.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtWeightedAverageInterestRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Average fixed interest rate related to the group of interest rate derivatives.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Nominal or face amount used to calculate payment on derivative.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5580258-113959

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5579245-113959

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
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-URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910

+ Details

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

- Definition

Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.

+ References

+ Details

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

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

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

- Definition

The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

+ References

No definition available.

+ Details

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

- Details

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- Details

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

- Details

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Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis=us-gaap_CashFlowHedgingMember
Namespace Prefix:
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Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=mgm_UnsecuredRevolvingCreditFacilityMember
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Data Type:	na
Balance Type:
Period Type:

- Details

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Period Type:

- Details

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- Details

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Long-Term Debt - Additional Information (Detail) - USD ($)	1 Months Ended	6 Months Ended
	Mar. 31, 2021	Jun. 30, 2021	Feb. 28, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Credit facility amount		$ 12,677,219,000		$ 12,480,586,000
Fair value of interest rate swaps designated as cash flow hedges recorded as liability				41,000,000
Fair value of interest rate swaps designated as cash flow hedges recorded as current liability				1,000,000
Fair value of interest rate swaps designated as cash flow hedges recorded as long-term liability		33,000,000		40,000,000
Fair value of interest rate swaps not designated as cash flow hedges recorded as liability		38,000,000		78,000,000
Fair value of interest rate swaps not designated as cash flow hedges recorded as current liability		11,000,000		31,000,000
Fair value of interest rate swaps not designated as cash flow hedges recorded as long-term liability		27,000,000		47,000,000
Long-term debt, fair value		$ 13,400,000,000		$ 13,200,000,000
4.75% MGM China senior notes, due 2027 [Member]
Debt Instrument [Line Items]
Long-term debt, maturity year	2027	2027
Long-term debt, principal amount	$ 750,000,000
Long-term debt, interest rate (as a percent)	4.75%	4.75%
Long term debt, issued price percentage	99.97%
Operating Partnership Senior Credit Facility [Member] \| Interest Rate Swap [Member]
Debt Instrument [Line Items]
Notional amount		$ 900,000,000
Operating Partnership Senior Credit Facility [Member] \| Interest Rate Swap [Member] \| Cash Flow Hedges [Member]
Debt Instrument [Line Items]
Notional amount		$ 700,000,000
Weighted Average fixed interest rate		1.783%
Revolving Credit Facility [Member] \| Operating Partnership Senior Credit Facility [Member]
Debt Instrument [Line Items]
Line of credit facility drawn		$ 0
Credit facility amount		1,350,000,000
Unsecured Revolving Credit Facility [Member \| MGM China First Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of credit facility		1,250,000,000
Unsecured Revolving Credit Facility [Member \| MGM China Second Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of credit facility		500,000,000
Line of credit facility drawn		0
Line of credit facility, current borrowing capacity		400,000,000
Term Loan [Member] \| MGM China First Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of credit facility drawn		$ 227,000,000
Debt instrument, weighted average interest rate		2.84%
Senior Credit Facility [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of credit facility		$ 1,500,000,000
Line of credit facility drawn		$ 0
Senior Credit Facility [Member] \| Revolving Credit Facility [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Increase the liquidity level including unrestricted cash, cash equivalents			$ 1,000,000,000.0