Annual term loan repayment percentage of initial aggregate principal amount.

No definition available.

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- Definition

Debt instrument covenant leverage ratio.

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Debt instrument maturity.

+ References

No definition available.

+ Details

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- Definition

Debt instrument maturity year.

+ References

No definition available.

+ Details

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Period Type:	duration

- Definition

Represents the amortization payments made as a percentage of debt instrument of the original principal amount.

+ References

No definition available.

+ Details

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Data Type:	num:percentItemType
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Period Type:	duration

- Definition

Represents the variable interest rate floor.

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	instant

- Definition

Debt repayment excess cash generates, percentage.

+ References

No definition available.

+ Details

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Data Type:	num:percentItemType
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Period Type:	duration

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
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Data Type:	num:percentItemType
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/presentationRef
-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 2: http://www.xbrl.org/2003/role/presentationRef
-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://www.xbrl.org/2003/role/presentationRef
-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

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

- Definition

Date the debt agreement requires the first payment to be made, in CCYY-MM-DD format.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6479336&loc=d3e64711-112823

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-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

+ Details

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

- Definition

The reference rate for the variable rate of the debt instrument, such as LIBOR or the US Treasury rate and the maturity of the reference rate used, such as three months or six months LIBOR.

+ References

No definition available.

+ Details

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

+ References

+ Details

Name:	us-gaap_DebtInstrumentInterestRateEffectivePercentage
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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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

+ References

+ Details

Name:	us-gaap_DebtInstrumentMaturityDate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of the required periodic payments applied to principal.

+ References

+ Details

Name:	us-gaap_DebtInstrumentPeriodicPaymentPrincipal
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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

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

+ Details

Name:	us-gaap_LineOfCredit
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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

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

- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

+ Details

Name:	us-gaap_LongTermDebtCurrent
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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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Data Type:	xbrli:monetaryItemType
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Period Type:	instant

- Definition

The cash outflow for debt initially having maturity due after one year or beyond the normal operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3291-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Financing Activities
-URI http://asc.fasb.org/extlink&oid=6513228

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- Details

Name:	us-gaap_LineOfCreditFacilityAxis=mgm_SeniorCreditFacilityMember
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Name:	us-gaap_DebtInstrumentAxis=mgm_SeniorSecuredTermLoanAMember
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Name:	us-gaap_VariableRateAxis=us-gaap_LondonInterbankOfferedRateLIBORMember
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Long-Term Debt - Additional Information (Detail) - USD ($)						1 Months Ended	3 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	May 01, 2017	Feb. 28, 2017	Jan. 31, 2017	Feb. 28, 2017	Mar. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Current portion of long-term debt							$ 0	$ 8,375,000
Credit facility amount							13,247,317,000	13,144,380,000
Long-term debt, fair value							$ 13,900,000,000	13,900,000,000
Minimum [Member]
Debt Instrument [Line Items]
Debt repayment excess cash, percentage							0.00%
Maximum [Member]
Debt Instrument [Line Items]
Debt repayment excess cash, percentage							50.00%
Senior Credit Facility [Member] \| Term Loan A [Member]
Debt Instrument [Line Items]
Credit facility amount							$ 250,000,000
Variable interest rate base							LIBOR
Credit facility, maturity date							2021-04
Term loan repayment percentage of initial aggregate principal amount							5.00%
Repayments of term loan							$ 3,000,000
Debt instrument, interest rate							3.23%
Senior Credit Facility [Member] \| Term Loan A [Member] \| Minimum [Member] \| After Six Months [Member] \| LIBOR [Member]
Debt Instrument [Line Items]
Interest rate margin (as a percent)							1.75%
Senior Credit Facility [Member] \| Term Loan A [Member] \| Maximum [Member] \| After Six Months [Member] \| LIBOR [Member]
Debt Instrument [Line Items]
Interest rate margin (as a percent)							2.75%
Senior Credit Facility [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Credit facility amount							$ 1,250,000,000
Credit facility, maturity date							2021-04
Line of credit facility drawn							$ 50,000,000
Debt instrument, interest rate							3.19%
Senior Credit Facility [Member] \| Term loans [Member]
Debt Instrument [Line Items]
Credit facility amount							$ 247,000,000
MGM Growth Properties Senior Credit Facility [Member]
Debt Instrument [Line Items]
Current portion of long-term debt								$ 8,000,000
MGM Growth Properties Senior Credit Facility [Member] \| Term Loan A [Member]
Debt Instrument [Line Items]
Term loan repayment percentage of initial aggregate principal amount							5.00%
Debt instrument, interest rate							3.73%
Line of credit facility							$ 285,000,000
Long-term debt, maturity year							2021
Repayments of term loan							$ 8,000,000
MGM Growth Properties Senior Credit Facility [Member] \| Term Loan A [Member] \| Minimum [Member] \| After Six Months [Member] \| LIBOR [Member]
Debt Instrument [Line Items]
Interest rate margin (as a percent)							2.25%
MGM Growth Properties Senior Credit Facility [Member] \| Term Loan A [Member] \| Maximum [Member] \| After Six Months [Member] \| LIBOR [Member]
Debt Instrument [Line Items]
Interest rate margin (as a percent)							2.75%
MGM Growth Properties Senior Credit Facility [Member] \| Term Loan B [Member]
Debt Instrument [Line Items]
Term loan repayment percentage of initial aggregate principal amount							1.00%
Debt instrument, interest rate							3.48%
Line of credit facility							$ 1,830,000,000
Long-term debt, maturity year							2023
Repayments of term loan							$ 9,000,000
MGM Growth Properties Senior Credit Facility [Member] \| Term Loan B [Member] \| Subsequent Event [Member]
Debt Instrument [Line Items]
Interest rate margin (as a percent)			2.25%
Interest rate floor (as a percent)			0.00%
MGM Growth Properties Senior Credit Facility [Member] \| Term Loan B [Member] \| LIBOR [Member]
Debt Instrument [Line Items]
Interest rate margin (as a percent)					2.75%
Interest rate floor (as a percent)					0.75%
MGM Growth Properties Senior Credit Facility [Member] \| Term Loan B [Member] \| LIBOR [Member] \| Corporate Family Ratings, Ba3/BB- [Member]
Debt Instrument [Line Items]
Interest rate margin (as a percent)				2.50%
Interest rate floor (as a percent)				0.75%		0.75%
MGM Growth Properties Senior Credit Facility [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of credit facility drawn							0
Line of credit facility							$ 600,000,000
Long-term debt, maturity year							2021
MGM Growth Properties Senior Credit Facility [Member] \| Revolving Credit Facility [Member] \| Minimum [Member] \| After Six Months [Member] \| LIBOR [Member]
Debt Instrument [Line Items]
Interest rate margin (as a percent)							2.25%
MGM Growth Properties Senior Credit Facility [Member] \| Revolving Credit Facility [Member] \| Maximum [Member] \| After Six Months [Member] \| LIBOR [Member]
Debt Instrument [Line Items]
Interest rate margin (as a percent)							2.75%
MGM China Credit Facility [Member]
Debt Instrument [Line Items]
Long-term debt, maturity date							Apr. 30, 2019
MGM China Credit Facility [Member] \| Hong Kong Interbank Offered Rate HIBOR [Member]
Debt Instrument [Line Items]
Variable interest rate base							HIBOR
MGM China Credit Facility [Member] \| Minimum [Member] \| Hong Kong Interbank Offered Rate HIBOR [Member]
Debt Instrument [Line Items]
Interest rate margin (as a percent)							1.375%
MGM China Credit Facility [Member] \| Maximum [Member] \| Hong Kong Interbank Offered Rate HIBOR [Member]
Debt Instrument [Line Items]
Interest rate margin (as a percent)							2.50%
MGM China Credit Facility [Member] \| Amended and Restated Credit Agreement [Member] \| Debt Covenant Terms Through December Thirty One Two Thousand And Seventeen [Member]
Debt Instrument [Line Items]
Leverage ratio						600.00%
MGM China Credit Facility [Member] \| Amended and Restated Credit Agreement [Member] \| Debt Covenant Terms March Thirty One Two Thousand And Eighteen [Member]
Debt Instrument [Line Items]
Leverage ratio						550.00%
MGM China Credit Facility [Member] \| Amended and Restated Credit Agreement [Member] \| Debt Covenant Terms June Thirty Two Thousand And Eighteen [Member]
Debt Instrument [Line Items]
Leverage ratio						500.00%
MGM China Credit Facility [Member] \| Amended and Restated Credit Agreement [Member] \| Debt Covenant Terms September Thirty Two Thousand And Eighteen And Thereafter [Member]
Debt Instrument [Line Items]
Leverage ratio						450.00%
MGM China Credit Facility [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of credit facility drawn							$ 450,000,000
Debt instrument, interest rate							2.45%
Line of credit facility							$ 1,450,000,000
MGM China Credit Facility [Member] \| Term loans [Member]
Debt Instrument [Line Items]
Credit facility amount							1,560,000,000
Line of credit facility							$ 1,550,000,000
Amortization payments of term loan beginning date							Oct. 31, 2017
Weighted average interest rate at the end of the period (as a percent)							2.44%
MGM National Harbor Credit Facility [Member]
Debt Instrument [Line Items]
Interest rate margin (as a percent)							2.25%
MGM National Harbor Credit Facility [Member] \| Scenario Forecast [Member]
Debt Instrument [Line Items]
Amortization payments of aggregate principal balance (as percent)	2.50%	1.875%
MGM National Harbor Credit Facility [Member] \| Term Loan A [Member]
Debt Instrument [Line Items]
Credit facility amount							$ 425,000,000
Debt instrument, interest rate							3.23%
MGM National Harbor Credit Facility [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Variable interest rate base							LIBOR
Line of credit facility drawn							$ 25,000,000
Debt instrument, interest rate							3.10%
Line of credit facility							$ 100,000,000
Long-term debt, maturity date							Jan. 31, 2021
Amortization payments of aggregate principal balance (as percent)							1.25%
MGM National Harbor Credit Facility [Member] \| Term loans [Member]
Debt Instrument [Line Items]
Credit facility amount							$ 425,000,000
Variable interest rate base							LIBOR
Long-term debt, maturity date							Jan. 31, 2021