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Label Element Value
Risk/Return: rr_RiskReturnAbstract  
Risk/Return [Heading] rr_RiskReturnHeading Core Plus Fixed Income Portfolio
Objective [Heading] rr_ObjectiveHeading Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock

The Core Plus Fixed Income Portfolio seeks above-average total return over a market cycle of three to five years.

Expense [Heading] rr_ExpenseHeading Fees and Expenses
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 section of this Prospectus entitled "Shareholder Information—Exchange Privilege") held in Related Accounts (as defined in the section of this Prospectus entitled "Shareholder Information—How To Purchase Class A Shares"), amounts to $25,000 or more. More information about this combined purchase discount and other discounts is available from your financial intermediary and in the section of this Prospectus entitled "Shareholder Information—How To Purchase Class A Shares."

Shareholder Fees Caption [Text] rr_ShareholderFeesCaption Shareholder Fees (fees paid directly from your investment)
Operating Expenses Caption [Text] rr_OperatingExpensesCaption Annual Portfolio Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Portfolio Turnover [Heading] rr_PortfolioTurnoverHeading Portfolio Turnover
Portfolio Turnover [Text Block] rr_PortfolioTurnoverTextBlock

The Portfolio pays transaction costs when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Portfolio shares are held in a taxable account. These costs, which are not reflected in Total Annual Portfolio Operating Expenses or in the Example, affect the Portfolio's performance. During the most recent fiscal year, the Portfolio's portfolio turnover rate was 296% of the average value of its portfolio.

Portfolio Turnover, Rate rr_PortfolioTurnoverRate 296.00%rr_PortfolioTurnoverRate
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock

The example below is intended to help you compare the cost of investing in the Portfolio with the cost of investing in other mutual funds.


The example assumes that you invest $10,000 in the Portfolio, your investment has a 5% return each year and that the Portfolio's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading] rr_StrategyHeading Principal Investment Strategies
Strategy Narrative [Text Block] rr_StrategyNarrativeTextBlock

Under normal circumstances, at least 80% of the Portfolio's assets will be invested in fixed income securities. This policy may be changed without shareholder approval; however, you would be notified in writing of any changes. The Portfolio invests primarily in a diversified mix of U.S. dollar-denominated investment grade fixed income securities, particularly U.S. government, corporate, municipal and mortgage-backed securities. The Portfolio will ordinarily seek to maintain an average weighted maturity between five and ten years.


The Adviser employs a value approach toward fixed income investing and evaluates the relative attractiveness among corporate, mortgage and U.S. government securities, and also may consider the relative attractiveness of non-dollar-denominated issues. The Adviser relies upon value measures to guide its decisions regarding sector, security and country selection, such as the relative attractiveness of the extra yield offered by securities other than those issued by the U.S. Treasury. The Adviser also measures various types of risk by monitoring interest rates, inflation, the shape of the yield curve, credit risk, prepayment risk, country risk and currency valuations.


The Portfolio may invest opportunistically in fixed income securities that are rated below "investment grade" or are not rated, but are of equivalent quality. These fixed income securities are often referred to as "high yield securities" or "junk bonds." High yield securities are fixed income securities rated below Baa3 by Moody's Investors Service, Inc. ("Moody's") or below BBB- by Standard & Poor's Rating Group, a division of The McGraw-Hill Companies, Inc. ("S&P"), or if unrated considered by the Adviser to be of equivalent quality. The Portfolio may also invest in public bank loans made by banks or other financial institutions. Public bank loans are privately negotiated loans that are not publicly traded for which information about the issuer has been made publicly available. These public bank loans may be rated investment grade or below investment grade. In addition, the Portfolio may invest in convertible securities.


The Portfolio's mortgage securities may include collateralized mortgage obligations ("CMOs"), commercial mortgage-backed securities ("CMBS"), stripped mortgage-backed securities ("SMBS") and inverse floating rate obligations ("inverse floaters"). In addition, the Portfolio may invest in to-be-announced pass-through mortgage securities, which settle on a delayed delivery basis ("TBAs"). The Portfolio may also invest in securities of foreign issuers, including issuers located in emerging market or developing countries. The securities in which the Portfolio may invest may be denominated in U.S. dollars or in currencies other than U.S. dollars. The Portfolio may also invest in restricted and illiquid securities.


The Portfolio may, but it is not required to, use derivative instruments for a variety of purposes, including hedging, risk management, portfolio management or to earn income. The Portfolio's use of derivatives may involve the purchase and sale of derivative instruments such as futures, options, swaps and other related instruments and techniques. The Portfolio may utilize foreign currency forward exchange contracts, which are also derivatives, in connection with its investments in foreign securities. Derivative instruments used by the Portfolio will be counted towards the 80% policy discussed above to the extent they have economic characteristics similar to the securities included within that policy.

Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock

There is no assurance that the Portfolio will achieve its investment objective and you can lose money investing in this Portfolio. The principal risks of investing in the Portfolio include:


•  Fixed Income Securities. Fixed income securities are subject to the risk of the issuer's inability to meet principal and interest payments on its obligations (i.e., credit risk) and are subject to price volatility resulting from, among other things, interest rate sensitivity, market perception of the creditworthiness of the issuer and general market liquidity (i.e., market risk). The historically low interest rate environment increases the risk associated with rising interest rates, including the potential for periods of volatility and increased redemptions. The Portfolio may face a heightened level of interest rate risk, especially since the Federal Reserve Board has ended its quantitative easing program and may begin to raise rates. Securities with longer durations are likely to be more sensitive to changes in interest rates, generally making them more volatile than securities with shorter durations. Lower rated fixed income securities have greater volatility because there is less certainty that principal and interest payments will be made as scheduled. A portion of the Portfolio's fixed income securities may be rated below investment grade. To the extent that the Portfolio invests in convertible securities, and the convertible security's investment value is greater than its conversion value, its price will be likely to increase when interest rates fall and decrease when interest rates rise. If the conversion value exceeds the investment value, the price of the convertible security will tend to fluctuate directly with the price of the underlying security.


•  Municipal Securities. Municipal obligations may be general obligations or revenue bonds. General obligation bonds are secured by the issuer's full faith and credit as well as its taxing power for payment of principal or interest. Revenue bonds are payable solely from the revenues derived from a specified revenue source, and therefore involve the risk that the revenues so derived will not be sufficient to meet interest and/or principal payment obligations. The value of municipal securities may be affected by political changes as well as uncertainties related to taxation, legislative developments and the rights of municipal security holders. Municipal securities and issuers of municipal securities may be more susceptible to downgrade, default and bankruptcy as a result of recent periods of economic stress. Municipal securities involve the risk that an issuer may call securities for redemption, which could force the Portfolio to reinvest the proceeds at a lower rate of interest.


•  High Yield Securities ("Junk Bonds"). The Portfolio's investments in high yield securities expose it to a substantial degree of credit risk. High yield securities may be issued by companies that are restructuring, are smaller and less creditworthy or are more highly indebted than other companies, and therefore they may have more difficulty making scheduled payments of principal and interest. High yield securities are subject to greater risk of loss of income and principal than higher rated securities and may be considered speculative. High yield securities may experience reduced liquidity, and sudden and substantial decreases in price. An economic downturn affecting an issuer of high yield securities may result in an increased incidence of default. In the event of a default, the Portfolio may incur additional expenses to seek recovery.


•  Public Bank Loans. Certain public bank loans are illiquid, meaning the Portfolio may not be able to sell them quickly at a fair price. To the extent a bank loan has been deemed illiquid, it will be subject to the Portfolio's restrictions on investment in illiquid securities. The secondary market for bank loans may be subject to irregular trading activity, wide bid/ask spreads and extended trade settlement periods. Bank loans are subject to the risk of default in the payment of interest or principal on a loan, which will result in a reduction of income to the Portfolio, and a potential decrease in the Portfolio's NAV. The risk of default will increase in the event of an economic downturn or a substantial increase in interest rates. Because public bank loans usually rank lower in priority of payment to senior loans, they present a greater degree of investment risk. These bank loans may exhibit greater price volatility as well.


•  Mortgage Securities. Investments in mortgage securities are subject to the risk that if interest rates decline, borrowers may pay off their mortgages sooner than expected which may adversely affect the Portfolio's return. Rising interest rates tend to discourage refinancings, with the result that the average life and volatility of mortgage securities will increase and market price will decrease. Rates of prepayment, faster or slower than expected by the Adviser, could reduce the Portfolio's yield, increase the volatility of the Portfolio and/or cause a decline in NAV. Certain mortgage-backed securities may be more volatile and less liquid than other traditional types of debt securities. In addition, an unexpectedly high rate of defaults on the mortgages held by a mortgage pool may adversely affect the value of a mortgage-backed security and could result in losses to the Portfolio. Investments in TBAs may give rise to a form of leverage and may cause the Portfolio's turnover rate to appear higher. Leverage may cause the Portfolio to be more volatile than if the Portfolio had not been leveraged.


•  U.S. Government Securities. The U.S. government securities in which the Portfolio invests can be subject to two types of risk: credit risk and interest rate risk. When the general level of interest rates goes up, the prices of most fixed income securities go down. When the general level of interest rates goes down, the prices of most fixed income securities go up. While the credit risk associated with U.S. government securities generally is considered to be minimal, the interest rate risk can be substantial. With respect to U.S. government securities that are not backed by the full faith and credit of the U.S. Government, there is the risk that the U.S. Government will not provide financial support to such U.S. government agencies, instrumentalities or sponsored enterprises if it is not obligated to do so by law.


•  Foreign and Emerging Market Securities. Investments in foreign markets entail special risks such as currency, political, economic and market risks. There also may be greater market volatility, less reliable financial information, higher transaction and custody costs, decreased market liquidity and less government and exchange regulation associated with investments in foreign markets. In addition, investments in certain foreign markets, which have historically been considered stable, may become more volatile and subject to increased risk due to ongoing developments and changing conditions in such markets. Moreover, the growing interconnectivity of global economies and financial markets has increased the probability that adverse developments and conditions in one country or region will affect the stability of economies and financial markets in other countries or regions. The risks of investing in emerging market countries are greater than risks associated with investments in foreign developed countries. In addition, the Portfolio's investments in foreign issuers may be denominated in foreign currencies and therefore, to the extent unhedged, the value of the investment will fluctuate with the U.S. dollar exchange rates. To the extent hedged by the use of foreign currency forward exchange contracts, the precise matching of the foreign currency forward exchange contract amounts and the value of the securities involved will not generally be possible because the future value of such securities in foreign currencies will change as a consequence of market movements in the value of those securities between the date on which the contract is entered into and the date it matures. There is additional risk that such transactions reduce or preclude the opportunity for gain if the value of the currency should move in the direction opposite to the position taken and that foreign currency forward exchange contracts create exposure to currencies in which the Portfolio's securities are not denominated. The use of foreign currency forward exchange contracts involves the risk of loss from the insolvency or bankruptcy of the counterparty to the contract or the failure of the counterparty to make payments or otherwise comply with the terms of the contract.


•  Liquidity. The Portfolio's investments in restricted and illiquid securities may entail greater risk than investments in publicly traded securities. These securities may be more difficult to sell, particularly in times of market turmoil. Additionally, the market for certain investments deemed liquid at the time of purchase may become illiquid under adverse market or economic conditions. Illiquid securities may be more difficult to value. If the Portfolio is forced to sell an illiquid security to fund redemptions or for other cash needs, it may be forced to sell the security at a loss.


•  Derivatives. A derivative instrument often has risks similar to its underlying asset and may have additional risks, including imperfect correlation between the value of the derivative and the underlying asset, risks of default by the counterparty to certain transactions, magnification of losses incurred due to changes in the market value of the securities, instruments, indices or interest rates to which they relate and risks that the transactions may not be liquid. Certain derivative transactions may give rise to a form of leverage. Leverage magnifies the potential for gain and the risk of loss.


Shares of the Portfolio are not bank deposits and are not guaranteed or insured by the Federal Deposit Insurance Corporation or any other government agency.

Risk Lose Money [Text] rr_RiskLoseMoney There is no assurance that the Portfolio will achieve its investment objective and you can lose money investing in this Portfolio.
Risk Not Insured Depository Institution [Text] rr_RiskNotInsuredDepositoryInstitution Shares of the Portfolio are not bank deposits and are not guaranteed or insured by the Federal Deposit Insurance Corporation or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Performance Information
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock

The bar chart and table below provide some indication of the risks of investing in the Portfolio by showing changes in the Portfolio's Class I shares' performance from year-to-year and by showing how the Portfolio's average annual returns for the past one, five and 10 year periods and since inception compare with those of a broad measure of market performance, as well as an index that represents a group of similar mutual funds, over time. The performance of the other Classes, which is shown in the table below, will differ because the Classes have different ongoing fees. The Portfolio's returns in the table include the maximum applicable sales charge for Class A and assume you sold your shares at the end of each period (unless otherwise noted). The Portfolio's past performance, before and after taxes, is not necessarily an indication of how the Portfolio will perform in the future. Updated performance information is available online at www.morganstanley.com/im.

Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns The bar chart and table below provide some indication of the risks of investing in the Portfolio by showing changes in the Portfolio's Class I shares' performance from year-to-year and by showing how the Portfolio's average annual returns for the past one, five and 10 year periods and since inception compare with those of a broad measure of market performance, as well as an index that represents a group of similar mutual funds, over time.
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress www.morganstanley.com/im
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture The Portfolio's past performance, before and after taxes, is not necessarily an indication of how the Portfolio will perform in the future.
Bar Chart [Heading] rr_BarChartHeading Annual Total Returns—Calendar Years
Bar Chart Closing [Text Block] rr_BarChartClosingTextBlock

High Quarter

 

9/30/09

   

4.79

%

 

Low Quarter

 

9/30/08

   

–7.10

%

 
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel High Quarter
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Sep. 30, 2009
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 4.79%rr_BarChartHighestQuarterlyReturn
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel Low Quarter
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Sep. 30, 2008
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (7.10%)rr_BarChartLowestQuarterlyReturn
Performance Table Does Reflect Sales Loads rr_PerformanceTableDoesReflectSalesLoads The Portfolio's returns in the table include the maximum applicable sales charge for Class A and assume you sold your shares at the end of each period (unless otherwise noted).
Index No Deduction for Fees, Expenses, Taxes [Text] rr_IndexNoDeductionForFeesExpensesTaxes (reflects no deduction for fees, expenses or taxes)
Performance Table Uses Highest Federal Rate rr_PerformanceTableUsesHighestFederalRate The after-tax returns shown in the table above are calculated using the historical highest individual federal marginal income tax rates during the period shown and do not reflect the impact of state and local taxes.
Performance Table Not Relevant to Tax Deferred rr_PerformanceTableNotRelevantToTaxDeferred Actual after-tax returns depend on the investor's tax situation and may differ from those shown, and after-tax returns are not relevant to investors who hold their Portfolio shares through tax deferred arrangements such as 401(k) plans or individual retirement accounts.
Performance Table One Class of after Tax Shown [Text] rr_PerformanceTableOneClassOfAfterTaxShown After-tax returns for the Portfolio's other Classes will vary from Class I shares' returns.
Performance Table Explanation after Tax Higher rr_PerformanceTableExplanationAfterTaxHigher After-tax returns may be higher than before-tax returns due to foreign tax credits and/or an assumed benefit from capital losses that would have been realized had Portfolio shares been sold at the end of the relevant periods, as applicable.
Performance Table Closing [Text Block] rr_PerformanceTableClosingTextBlock

The after-tax returns shown in the table above are calculated using the historical highest individual federal marginal income tax rates during the period shown and do not reflect the impact of state and local taxes. After-tax returns for the Portfolio's other Classes will vary from Class I shares' returns. Actual after-tax returns depend on the investor's tax situation and may differ from those shown, and after-tax returns are not relevant to investors who hold their Portfolio shares through tax deferred arrangements such as 401(k) plans or individual retirement accounts. After-tax returns may be higher than before-tax returns due to foreign tax credits and/or an assumed benefit from capital losses that would have been realized had Portfolio shares been sold at the end of the relevant periods, as applicable.

Caption rr_AverageAnnualReturnCaption Average Annual Total Returns (for periods ended December 31, 2014)
Barclays U.S. Aggregate Index (reflects no deduction for fees, expenses or taxes)
  
Risk/Return: rr_RiskReturnAbstract  
Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 5.97%rr_AverageAnnualReturnYear01
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Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 4.45%rr_AverageAnnualReturnYear05
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Average Annual Returns, 10 Years rr_AverageAnnualReturnYear10 4.71%rr_AverageAnnualReturnYear10
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Average Annual Returns, Since Inception rr_AverageAnnualReturnSinceInception 7.50%rr_AverageAnnualReturnSinceInception
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Average Annual Returns, Inception Date rr_AverageAnnualReturnInceptionDate Nov. 14, 1984 [1]
Lipper Core Plus Bond Funds Index (reflects no deduction for taxes)
  
Risk/Return: rr_RiskReturnAbstract  
Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 5.62%rr_AverageAnnualReturnYear01
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Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 5.62%rr_AverageAnnualReturnYear05
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Average Annual Returns, 10 Years rr_AverageAnnualReturnYear10 5.34%rr_AverageAnnualReturnYear10
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Average Annual Returns, Since Inception rr_AverageAnnualReturnSinceInception    [3]
Class I Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases (as a percentage of offering price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) (as a percentage based on the lesser of the offering price or NAV at redemption) rr_MaximumDeferredSalesChargeOverOther none
Advisory Fee rr_ManagementFeesOverAssets 0.375%rr_ManagementFeesOverAssets
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Distribution and/or Shareholder Service (12b-1) Fee rr_DistributionAndService12b1FeesOverAssets none
Other Expenses rr_OtherExpensesOverAssets 0.43%rr_OtherExpensesOverAssets
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Total Annual Portfolio Operating Expenses rr_ExpensesOverAssets 0.81%rr_ExpensesOverAssets
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Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets (0.29%)rr_FeeWaiverOrReimbursementOverAssets
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Total Annual Portfolio Operating Expenses After Fee Waiver and/or Expense Reimbursement rr_NetExpensesOverAssets 0.52%rr_NetExpensesOverAssets
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Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 53rr_ExpenseExampleYear01
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Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 167rr_ExpenseExampleYear03
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Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 291rr_ExpenseExampleYear05
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Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 653rr_ExpenseExampleYear10
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Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 8.08%rr_AverageAnnualReturnYear01
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Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 6.30%rr_AverageAnnualReturnYear05
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Average Annual Returns, 10 Years rr_AverageAnnualReturnYear10 3.80%rr_AverageAnnualReturnYear10
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Average Annual Returns, Since Inception rr_AverageAnnualReturnSinceInception 7.43%rr_AverageAnnualReturnSinceInception
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Average Annual Returns, Inception Date rr_AverageAnnualReturnInceptionDate Nov. 14, 1984
Class I Shares | After Taxes on Distributions
  
Risk/Return: rr_RiskReturnAbstract  
Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 6.67%rr_AverageAnnualReturnYear01
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Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 4.68%rr_AverageAnnualReturnYear05
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Average Annual Returns, 10 Years rr_AverageAnnualReturnYear10 2.01%rr_AverageAnnualReturnYear10
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Average Annual Returns, Since Inception rr_AverageAnnualReturnSinceInception 4.71%rr_AverageAnnualReturnSinceInception
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Class I Shares | After Taxes on Distributions and Sale of Fund Shares
  
Risk/Return: rr_RiskReturnAbstract  
Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 4.55%rr_AverageAnnualReturnYear01
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Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 4.23%rr_AverageAnnualReturnYear05
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Average Annual Returns, 10 Years rr_AverageAnnualReturnYear10 2.21%rr_AverageAnnualReturnYear10
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Average Annual Returns, Since Inception rr_AverageAnnualReturnSinceInception 4.74%rr_AverageAnnualReturnSinceInception
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Class A Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases (as a percentage of offering price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice 4.25%rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice
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Maximum deferred sales charge (load) (as a percentage based on the lesser of the offering price or NAV at redemption) rr_MaximumDeferredSalesChargeOverOther none [5]
Advisory Fee rr_ManagementFeesOverAssets 0.375%rr_ManagementFeesOverAssets
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Distribution and/or Shareholder Service (12b-1) Fee rr_DistributionAndService12b1FeesOverAssets 0.25%rr_DistributionAndService12b1FeesOverAssets
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Other Expenses rr_OtherExpensesOverAssets 0.48%rr_OtherExpensesOverAssets
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Total Annual Portfolio Operating Expenses rr_ExpensesOverAssets 1.11%rr_ExpensesOverAssets
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Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets (0.24%)rr_FeeWaiverOrReimbursementOverAssets
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Total Annual Portfolio Operating Expenses After Fee Waiver and/or Expense Reimbursement rr_NetExpensesOverAssets 0.87%rr_NetExpensesOverAssets
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Expenses Deferred Charges [Text Block] rr_ExpensesDeferredChargesTextBlock Investments that are not subject to any sales charges at the time of purchase are subject to a contingent deferred sales charge ("CDSC") of 0.50% that will be imposed if you sell your shares within 18 months after the last day of the month of purchase, except for certain specific circumstances.
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 section of this Prospectus entitled "Shareholder Information—Exchange Privilege") held in Related Accounts (as defined in the section of this Prospectus entitled "Shareholder Information—How To Purchase Class A Shares"), amounts to $25,000 or more.
Expense Breakpoint, Minimum Investment Required [Amount] rr_ExpenseBreakpointMinimumInvestmentRequiredAmount 25,000rr_ExpenseBreakpointMinimumInvestmentRequiredAmount
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Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 510rr_ExpenseExampleYear01
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Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 691rr_ExpenseExampleYear03
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Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 887rr_ExpenseExampleYear05
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Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,452rr_ExpenseExampleYear10
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Annual Return 2005 rr_AnnualReturn2005 4.81%rr_AnnualReturn2005
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Annual Return 2006 rr_AnnualReturn2006 4.08%rr_AnnualReturn2006
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Annual Return 2007 rr_AnnualReturn2007 5.13%rr_AnnualReturn2007
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Annual Return 2008 rr_AnnualReturn2008 (16.42%)rr_AnnualReturn2008
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Annual Return 2009 rr_AnnualReturn2009 11.62%rr_AnnualReturn2009
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Annual Return 2010 rr_AnnualReturn2010 7.78%rr_AnnualReturn2010
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Annual Return 2011 rr_AnnualReturn2011 6.19%rr_AnnualReturn2011
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Annual Return 2012 rr_AnnualReturn2012 10.00%rr_AnnualReturn2012
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Annual Return 2013 rr_AnnualReturn2013 (0.23%)rr_AnnualReturn2013
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Annual Return 2014 rr_AnnualReturn2014 8.08%rr_AnnualReturn2014
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Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 3.10%rr_AverageAnnualReturnYear01
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Average Annual Returns, 5 Years rr_AverageAnnualReturnYear05 5.09%rr_AverageAnnualReturnYear05
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Average Annual Returns, 10 Years rr_AverageAnnualReturnYear10 3.08%rr_AverageAnnualReturnYear10
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Average Annual Returns, Since Inception rr_AverageAnnualReturnSinceInception 4.55%rr_AverageAnnualReturnSinceInception
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Average Annual Returns, Inception Date rr_AverageAnnualReturnInceptionDate Nov. 07, 1996
Class L
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases (as a percentage of offering price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) (as a percentage based on the lesser of the offering price or NAV at redemption) rr_MaximumDeferredSalesChargeOverOther none
Advisory Fee rr_ManagementFeesOverAssets 0.375%rr_ManagementFeesOverAssets
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Distribution and/or Shareholder Service (12b-1) Fee rr_DistributionAndService12b1FeesOverAssets 0.50%rr_DistributionAndService12b1FeesOverAssets
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Other Expenses rr_OtherExpensesOverAssets 2.22%rr_OtherExpensesOverAssets
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Total Annual Portfolio Operating Expenses rr_ExpensesOverAssets 3.10%rr_ExpensesOverAssets
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Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets (1.98%)rr_FeeWaiverOrReimbursementOverAssets
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Total Annual Portfolio Operating Expenses After Fee Waiver and/or Expense Reimbursement rr_NetExpensesOverAssets 1.12%rr_NetExpensesOverAssets
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Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 114rr_ExpenseExampleYear01
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Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 356rr_ExpenseExampleYear03
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Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 617rr_ExpenseExampleYear05
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Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,363rr_ExpenseExampleYear10
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Average Annual Returns, 1 Year rr_AverageAnnualReturnYear01 7.56%rr_AverageAnnualReturnYear01
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Average Annual Returns, Since Inception rr_AverageAnnualReturnSinceInception 4.50%rr_AverageAnnualReturnSinceInception
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Average Annual Returns, Inception Date rr_AverageAnnualReturnInceptionDate Apr. 27, 2012
[1] The Barclays U.S. Aggregate Index tracks the performance of U.S. government agency and Treasury securities, investment-grade corporate debt securities, agency mortgage-backed securities, asset-backed securities and commercial mortgage-backed securities. It is not possible to invest directly in an index.
[2] Since Inception reflects the inception date of Class I.
[3] The Lipper Core Plus Bond Funds Index is an equally weighted performance index of the largest qualifying funds (based on net assets) in the Lipper Core Plus Bond Funds classification. There are currently 30 funds represented in this Index.
[4] The Portfolio's "Adviser," Morgan Stanley Investment Management Inc., has agreed to reduce its advisory fee and/or reimburse the Portfolio so that Total Annual Portfolio Operating Expenses, excluding certain investment related expenses, taxes, interest and other extraordinary expenses (including litigation), will not exceed 0.52% for Class I, 0.87% for Class A and 1.12% for Class L. The fee waivers and/or expense reimbursements will continue for at least one year or until such time as the Fund's Board of Trustees acts to discontinue all or a portion of such waivers and/or reimbursements when it deems such action is appropriate.
[5] Investments that are not subject to any sales charges at the time of purchase are subject to a contingent deferred sales charge ("CDSC") of 0.50% that will be imposed if you sell your shares within 18 months after the last day of the month of purchase, except for certain specific circumstances. See "Shareholder Information-How to Redeem Shares-Class A Shares" for further information about the CDSC waiver categories.