Label	Element	Value
Emerging Markets Leaders Portfolio
Risk/Return:	rr_RiskReturnAbstract
Supplement to Prospectus [Text Block]	rr_SupplementToProspectusTextBlock	Prospectus Supplement June 18, 2020 Morgan Stanley Institutional Fund, Inc. Supplement dated June 18, 2020 to the Morgan Stanley Institutional Fund, Inc. Prospectus dated April 30, 2020 Emerging Markets Leaders Portfolio
Risk/Return [Heading]	rr_RiskReturnHeading	Emerging Markets Leaders Portfolio
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The second sentence of the seventh paragraph of the section of the Prospectus entitled "Fund Summary—Emerging Markets Leaders Portfolio—Principal Investment Strategies" is hereby deleted and replaced with the following: The Fund's use of derivatives may involve the purchase and sale of derivative instruments such as options, futures, swaps, CFDs, structured investments and other related instruments and techniques. Please retain this supplement for future reference.

No definition available.

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- Definition

Risk/Return Summary Investment Objectives/Goals Include the following information, in plain English under rule 421(d) under the Securities Act, in the order and subject matter indicated

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Form
-Number N-1A
-Chapter A
-Section 2

+ Details

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- Definition

Principal investment strategies of the Fund. Summarize how the Fund intends to achieve its investment objectives by identifying the Fund's principal investment strategies (including the type or types of securities in which the Fund invests or will invest principally) and any policy to concentrate in securities of issuers in a particular industry or group of industries.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Form
-Number N-1A
-Chapter A
-Section 4
-Subsection a

+ Details

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- Definition

This element contains the text of a prospectus supplement (submission type 497) not already contained in an element containing amended text or other data from a previous submission.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Form
-Number N-1A

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