Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Supplement [Text Block]	ck0000741375_SupplementTextBlock	Prospectus Supplement September 17, 2013 Morgan Stanley Institutional Fund Trust Supplement dated September 17, 2013 to the Morgan Stanley Institutional Fund, Inc. (the "Fund") Prospectus dated January 31, 2013 of: Core Plus Fixed Income Portfolio
Risk/Return [Heading]	rr_RiskReturnHeading	Core Plus Fixed Income Portfolio
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	The table below describes the fees and expenses that you may pay if you buy and hold shares of the Portfolio. For purchases of Class A shares, you may qualify for a sales charge discount if the cumulative net asset value ("NAV") of Class A shares of the Portfolio purchased in a single transaction, together with the NAV of all Class A shares of other portfolios of Morgan Stanley Institutional Fund Trust (the "Fund") or Class A shares of other Morgan Stanley Multi-Class Funds (as defined in the "General Shareholder Information—Exchange Privilege" section on page 49 of this Prospectus) held in Related Accounts (as defined in the "Purchasing Class A Shares" section on page 43 of this Prospectus), amounts to $25,000 or more. More information about this combined purchase discount and other discounts is available from your financial adviser and in the "Purchasing Class A Shares" section on page 43 of this Prospectus. Please retain this supplement for future reference.
Class A Shares
Risk/Return:	rr_RiskReturnAbstract
Expense Breakpoint Discounts [Text]	rr_ExpenseBreakpointDiscounts	For purchases of Class A shares, you may qualify for a sales charge discount if the cumulative net asset value ("NAV") of Class A shares of the Portfolio purchased in a single transaction, together with the NAV of all Class A shares of other portfolios of Morgan Stanley Institutional Fund Trust (the "Fund") or Class A shares of other Morgan Stanley Multi-Class Funds (as defined in the "General Shareholder Information-Exchange Privilege" section on page 49 of this Prospectus) held in Related Accounts (as defined in the "Purchasing Class A Shares" section on page 43 of this Prospectus), amounts to $25,000 or more.
Expense Breakpoint, Minimum Investment Required [Amount]	rr_ExpenseBreakpointMinimumInvestmentRequiredAmount	$ 25,000

No authoritative reference available.

No definition available.

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- Definition

Include the narrative explanations in the order indicated. A Fund may modify the narrative explanations if the explanation contains comparable information to that shown. The narrative explanation regarding sales charge discounts is only required by a Fund that offers such discounts and should specify the minimum level of investment required to qualify for a discount.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Form

-Number N-1A

-Chapter A

-Section 3

-Subsection instructions

-Paragraph 1

-Subparagraph b

+ Details

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- Definition

This element represents the minimum level of investment required to qualify for discounted sales charges or fund expenses (SEC Form N-1A 2006-09-14 A.3.instructions.1.b).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Form

-Number N-1A

-Chapter A

-Section 3

-Subsection instructions

-Paragraph 1

-Subparagraph b

+ Details

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Namespace Prefix:	rr_
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- Definition

This table describes the fees and expenses that you may pay if you buy and hold shared of the Fund. You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $[_____] in [name of fund family] funds. Include the narrative explanations in the order indicated. A Fund may modify the narrative explanations if the explanation contains comparable information to that shown. The narrative explanation regarding sales charge discounts is only required by a Fund that offers such discounts and should specify the minimum level of investment required to qualify for a discount. Modify the narrative explanation to state that Fund shares are sold on a national securities exchange at the end of the time periods indicated, and that brokerage commissions for buying and selling Fund shares through a broker are not reflected.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Form

-Number N-1A

-Chapter A

-Section 3

-Subsection instructions

-Paragraph 1

-Subparagraph b

+ Details

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- Details

Name:	rr_RiskReturnAbstract
Namespace Prefix:	rr_
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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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