Impairment loss from discontinuing operation.

No definition available.

Name:	mgm_ImpairmentLossFromDiscontinuingOperation
Namespace Prefix:	mgm_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Percentage of share of impairment charge offset.

+ References

No definition available.

+ Details

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Namespace Prefix:	mgm_
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Period Type:	duration

- Definition

Realized gain (loss) percentage on disposal of portion of equity method investments.

+ References

No definition available.

+ Details

Name:	mgm_RealizedGainLossPercentageOnDisposalOfPortionOfEquityMethodInvestments
Namespace Prefix:	mgm_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Reversal of basis differences.

+ References

No definition available.

+ Details

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

- Definition

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

+ References

No definition available.

+ Details

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

- 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/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=66011266&loc=d3e33918-111571

+ Details

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

- Definition

Amount of gain (loss) on sale or disposal of an equity method investment.

+ References

No definition available.

+ Details

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

- 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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- Details

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- Details

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Namespace Prefix:
Data Type:	na
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- Details

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Namespace Prefix:
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- Details

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- Details

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Investments in and Advances to Unconsolidated Affiliates - Additional Information (Detail) - USD ($) $ in Millions	1 Months Ended	3 Months Ended
	Apr. 30, 2018	Mar. 31, 2018	Dec. 31, 2017
Mandarin Oriental [Member]
Schedule Of Equity Method Investments [Line Items]
Consideration received from sale of discontinued operations		$ 214
Impairment loss from discontinuing operation		127
CityCenter Holdings LLC As Investee [Member]
Schedule Of Equity Method Investments [Line Items]
Reversal of basis differences		$ 64
Percentage of share of impairment charge offset		50.00%
Percentage ownership interest		50.00%	50.00%
Grand Victoria as Investee [Member]
Schedule Of Equity Method Investments [Line Items]
Percentage ownership interest		50.00%	50.00%
Grand Victoria as Investee [Member] \| Subsequent Event [Member]
Schedule Of Equity Method Investments [Line Items]
Percentage ownership interest	50.00%
Realized gain (loss) percentage	50.00%
Recognized gain on sale, unconsolidated affiliates	$ 162
Grand Victoria [Member]
Schedule Of Equity Method Investments [Line Items]
Percentage ownership interest		50.00%
Grand Victoria [Member] \| Subsequent Event [Member]
Schedule Of Equity Method Investments [Line Items]
Consideration received from sale of discontinued operations	$ 328