Objective, Primary [Text Block]

rr_ProspectusTable

Objective [Heading]

rr_ObjectiveHeading

Investment Objective

rr_ObjectivePrimaryTextBlock

The Global Strategist Portfolio (the “Fund”) 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, hold and sell shares of the Fund. You may pay fees other than the fees and expenses of the Fund, such as brokerage commissions and other fees charged by financial intermediaries, which are not reflected in the tables and examples below.

For purchases of Class A shares, you may qualify for a sales charge discount if the cumulative net asset value per share (“NAV”) of Class A shares of the Fund being purchased in a single transaction, together with the NAV of any Class A, Class L and Class C shares of the Fund already held in Related Accounts (as defined in the section of the Prospectus entitled “Shareholder Information—Sales Charges Applicable to Purchases of Class A Shares”) as of the date of the transaction as well as Class A, Class L and Class C shares of any other Morgan Stanley Multi-Class Fund excluding Morgan Stanley Institutional Fund Trust Short Duration Income, Ultra-Short Income and Ultra-Short Municipal Income Portfolios (as defined in the section of the Prospectus entitled “Shareholder Information—Exchange Privilege”) and including shares of Morgan Stanley Money Market Funds (as defined in the section of the Prospectus entitled “Shareholder Information—Exchange Privilege”) that you acquired in an exchange of Class A, Class L or Class C shares of the Fund or Class A, Class L or Class C shares of another Morgan Stanley Multi-Class Fund excluding Morgan Stanley Institutional Fund Trust Short Duration Income, Ultra-Short Income and Ultra-Short Municipal Income Portfolios already held in Related Accounts as of the date of the transaction, amounts to $25,000 or more. More information about this combined purchase discount and other discounts is available from your financial intermediary, on page 26 of the Prospectus in the section entitled “Shareholder Information—Sales Charges Applicable to Purchases of Class A Shares” and in Appendix A attached to the Prospectus.

Class I shares may be available on brokerage platforms of firms that have agreements with the Fund’s principal underwriter permitting such firms to (i) offer Class I shares solely when acting as an agent for the investor and (ii) impose on an investor transacting in Class I shares through such platforms a commission and/or other forms of compensation to the broker. Shares of the Fund are available in other share classes that have different fees and expenses.

Expense Breakpoint Discounts [Text]

rr_ExpenseBreakpointDiscounts

Expense Breakpoint, Minimum Investment Required [Amount]

rr_ExpenseBreakpointMinimumInvestmentRequiredAmount

$ 25,000

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

Shareholder Fees (fees paid directly from your investment)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

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 Fund with the cost of investing in other mutual funds.

The example assumes that you invest $10,000 in the Fund, your investment has a 5% return each year and that the Fund’s operating expenses remain the same (except that the example incorporates the fee waiver and/or expense reimbursement arrangement for only the first year). After eight years, Class C shares of the Fund generally will convert automatically to Class A shares of the Fund. The example for Class C shares reflects the conversion to Class A shares after eight years. Please refer to the section of the Prospectus entitled “Shareholder Information—Conversion Features” for more information. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example by, Year, Caption [Text]

rr_ExpenseExampleByYearCaption

If You SOLD Your Shares

Expense Example, No Redemption, By Year, Caption [Text]

rr_ExpenseExampleNoRedemptionByYearCaption

If You HELD Your Shares

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio Turnover

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The Fund pays transaction costs, such as commissions, 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 Fund shares are held in a taxable account. These costs, which are not reflected in Total Annual Fund Operating Expenses or in the Example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 115% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

115.00%

Strategy [Heading]

rr_StrategyHeading

Principal Investment Strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The Adviser and/or “Sub-Adviser,” Morgan Stanley Investment Management Limited, seek to achieve the Fund’s investment objective by investing primarily in a blend of equity and fixed-income securities of U.S. and non-U.S. issuers. Equity securities may include common and preferred stocks, depositary receipts, convertible securities, equity-linked securities, real estate investment trusts (“REITs”), rights and warrants to purchase equity securities and limited partnership interests. Fixed-income securities may include mortgage-related or mortgage-backed securities, floating rate securities, inflation-linked fixed-income securities, securities issued or guaranteed by the U.S. Government, its agencies or instrumentalities, securities issued or guaranteed by non-U.S. governments, their agencies or instrumentalities, corporate bonds and notes issued by U.S. and non-U.S. entities.

The Adviser and/or Sub-Adviser will utilize a top-down investment approach that focuses on asset class, sector, region, country and currency and thematic allocations. The Fund’s allocations will be based upon the Adviser’s and/or Sub-Adviser’s evaluations and analyses, taking into account results of its fundamental market research and recommendations generated by the Adviser’s and/or Sub-Adviser’s quantitative models. The Adviser’s and/or Sub-Adviser’s research process focuses on the following factors across asset classes: 1) valuation (both relative and absolute), 2) dynamics, including earnings revisions, interest rate policy and inflation expectations and 3) technicals, such as investor flows and sentiment. The Fund may invest in any country, including developing or emerging market countries. The Fund’s investments may be U.S. and non-U.S. dollar denominated. In determining whether to sell a security, the Adviser and/or Sub-Adviser consider a number of factors, including changes in capital appreciation potential, or the overall assessment of asset class, sector, region, country, and currency and thematic allocation shifts.

The Fund may invest a portion of its assets in below investment grade fixed-income securities (commonly referred to as “junk bonds”). The Fund may also invest in restricted and illiquid securities. The mortgage-backed securities in which the Fund may invest

include mortgage pass-through securities that represent a participation interest in a pool of mortgage loans originated by U.S. governmental or private lenders such as banks.

The Fund may also invest up to 10% of its total assets in other investment companies, including exchange-traded funds (“ETFs”).

The Fund may, but it is not required to, use derivative instruments for a variety of purposes, including hedging, risk management, Fund management or to earn income. The Fund’s use of derivatives may involve the purchase and sale of derivative instruments such as futures, options, swaps and structured investments (including commodity-linked notes), and other related instruments and techniques. The Fund may utilize foreign currency forward exchange contracts, which are also derivatives, in connection with its investments in foreign securities. Derivative instruments used by the Fund will be counted toward the Fund’s exposure to the types of securities listed above to the extent they have economic characteristics similar to such securities.

The Fund may, consistent with its principal investment strategies, invest up to 25% of its total assets in a wholly-owned subsidiary of the Fund organized as a company under the laws of the Cayman Islands (the “Subsidiary”). The Subsidiary may invest, directly or indirectly through the use of derivatives, in securities, commodities, commodity-related instruments and other investments, primarily futures, swaps and notes. The Subsidiary is advised by the Adviser.

Investments in the Subsidiary are intended to provide the Fund with exposure to commodities markets within the limitations of the federal tax requirements that apply to the Fund. The Subsidiary primarily obtains its commodity exposure by investing in commodity-linked derivative instruments, which may include, but are not limited to, total return swaps, commodity (U.S. or foreign) futures and commodity-linked notes. The Subsidiary may also invest in other instruments, including fixed-income securities, either as investments or to serve as margin or collateral for its swap positions, and foreign currency transactions (including forward contracts).

Risk [Heading]

rr_RiskHeading

Principal Risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

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

•

Equity Securities. In general, prices of equity securities are more volatile than those of fixed-income securities. The prices of equity securities fluctuate, and sometimes widely fluctuate, in response to activities specific to the issuer of the security as well as factors unrelated to the fundamental condition of the issuer, including general market, economic and political conditions. To the extent that the Fund 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.

•

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 (i.e., interest rate risk), market perception of the creditworthiness of the issuer and general market liquidity (i.e., market risk). The Fund may face a heightened level of interest rate risk in times of monetary policy change and/or uncertainty, such as when the Federal Reserve Board adjusts a quantitative easing program and/or changes rates. A changing interest rate environment increases certain risks, including the potential for periods of volatility, increased redemptions, shortened durations (i.e., prepayment risk) and extended durations (i.e., extension risk). The Fund is not limited as to the maturities (when a debt security provides its final payment) or durations (measure of interest rate sensitivity) of the securities in which it may invest. 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 Fund’s fixed-income securities may be rated below investment grade. Investing in emerging markets intensifies this risk, because lower quality fixed-income securities are more volatile in price.

•

High Yield Securities (“Junk Bonds”). The Fund’s investments in high yield securities expose it to a substantial degree of credit risk. Investing in emerging markets intensifies risk, because high yield securities may be more volatile in price in certain environments. 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 Fund may incur additional expenses to seek recovery.

•

Mortgage-Backed Securities. Mortgage-backed securities entail prepayment risk, which generally increases during a period of falling interest rates. Rising interest rates tend to discourage refinancings, with the result that the average life and volatility of mortgage-backed securities will increase and market price will decrease. Rates of prepayment, faster or slower than expected by the Adviser, could reduce the Fund’s yield, increase the volatility of the Fund and/or cause a decline in NAV. Mortgage-backed

securities are also subject to extension risk, which is the risk that rising interest rates could cause mortgages or other obligations underlying the securities to be prepaid more slowly than expected, thereby lengthening the duration of such securities, increasing their sensitivity to interest rate changes and causing their prices to decline. Certain mortgage-backed securities may be more volatile and less liquid than other traditional types of debt securities. In addition, mortgage-backed securities are subject to credit risk. 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 Fund. The risk of such defaults is generally higher in the case of mortgage pools that include subprime mortgages. Furthermore, mortgage-backed securities may be subject to risks associated with the assets underlying those securities, such as a decline in value. Investments in mortgage-backed securities may give rise to a form of leverage (indebtedness) and may cause the Fund’s portfolio turnover rate to appear higher. Leverage may cause the Fund to be more volatile than if the Fund had not been leveraged. The risks associated with mortgage-backed securities typically become elevated during periods of distressed economic, market, health and labor conditions. In particular, increased levels of unemployment, delays and delinquencies in payments of mortgage and rent obligations, and uncertainty regarding the effects and extent of government intervention with respect to mortgage payments and other economic matters may adversely affect the Fund’s investments in mortgage-backed securities.

•

REITs. Investing in REITs exposes investors to the risks of owning real estate directly, as well as to risks that relate specifically to the way in which REITs are organized and operated. Operating REITs requires specialized management skills and the Fund indirectly bears management expenses along with the direct expenses of the Fund. REITs are also subject to certain provisions under federal tax law and the failure of a company to qualify as a REIT could have adverse consequences for the Fund.

•

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, less stringent investor protections and disclosure standards, 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 that 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. Certain foreign markets may rely heavily on particular industries or foreign capital and are more vulnerable to diplomatic developments, the imposition of economic sanctions against a particular country or countries, organizations, companies, entities and/or individuals, changes in international trading patterns, trade barriers and other protectionist or retaliatory measures. Investments in foreign markets may also be adversely affected by governmental actions such as the imposition of capital controls, nationalization of companies or industries, expropriation of assets or the imposition of punitive taxes. The governments of certain countries may prohibit or impose substantial restrictions on foreign investing in their capital markets or in certain sectors or industries. In addition, a foreign government may limit or cause delay in the convertibility or repatriation of its currency which would adversely affect the U.S. dollar value and/or liquidity of investments denominated in that currency. Certain foreign investments may become less liquid in response to market developments or adverse investor perceptions, or become illiquid after purchase by the Fund, particularly during periods of market turmoil. When the Fund holds illiquid investments, its portfolio may be harder to value. The risks of investing in emerging market countries are greater than the risks associated with investments in foreign developed countries. Certain emerging market countries may be subject to less stringent requirements regarding accounting, auditing, financial reporting and record keeping and therefore, material information related to an investment may not be available or reliable. In addition, the Fund is limited in its ability to exercise its legal rights or enforce a counterparty’s legal obligations in certain jurisdictions outside of the United States, in particular, in emerging markets countries. Certain emerging market or developing countries are among the largest debtors to commercial banks and foreign governments. The issuer or governmental authority that controls the repayment of sovereign debt may not be willing or able to repay the principal and/or pay interest when due in accordance with the terms of such obligations. In addition, foreign governments may default on their debt securities, which may require holders of such securities to participate in debt rescheduling or additional lending to defaulting governments. Moreover, there is no bankruptcy proceeding by which defaulted sovereign debt may be collected in whole or in part. In addition, the Fund’s investments in foreign issuers may be denominated in foreign currencies and therefore, to the extent unhedged, the value of those investments will fluctuate with 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 may 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 Fund’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. Economic sanctions may be, and have been, imposed against certain countries, organizations, companies, entities and/or individuals. Economic sanctions and other similar governmental actions could, among other things, effectively restrict or eliminate the Fund’s ability to purchase or sell securities or groups of securities, and thus may make the Fund’s investments in such

securities less liquid or more difficult to value. In addition, as a result of economic sanctions, the Fund may be forced to sell or otherwise dispose of investments at inopportune times or prices.

•

U.S. Government Securities. Different types of U.S. government securities are subject to different levels of credit risk, including the risk of default, depending on the nature of the particular government support for that security. For example, a U.S. government-sponsored entity, such as Federal National Mortgage Association or Federal Home Loan Mortgage Corporation, although chartered or sponsored by an Act of Congress, may issue securities that are neither insured nor guaranteed by the U.S. Treasury and, therefore, are not backed by the full faith and credit of the United States. With respect to U.S. government securities that are not backed by the full faith and credit of the United States, 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.

•

Liquidity. The Fund may make investments that are illiquid or restricted or that may become less liquid in response to overall economic conditions or adverse investor perceptions, and which may entail greater risk than investments in other types of securities. These investments may be more difficult to value or sell, particularly in times of market turmoil, and there may be little trading in the secondary market available for particular securities. Liquidity risk may be magnified in a market where credit spread and interest rate volatility is rising and where investor redemptions from fixed-income mutual funds may be higher than normal. If the Fund is forced to sell an illiquid or restricted security to fund redemptions or for other cash needs, it may be forced to sell the security at a loss or for less than its fair value.

•

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 the derivative instrument relates 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. Investments in currency derivatives may substantially change the Fund’s exposure to currency exchange rates and could result in losses to the Fund if currencies do not perform as the Adviser expects. Foreign currency forward exchange contracts and currency futures and options contracts create exposure to currencies in which the Fund’s securities are not denominated.

•

LIBOR Discontinuance or Unavailability Risk. The London InterBank Offered Rate (“LIBOR”) is intended to represent the rate at which contributing banks may obtain short-term borrowings from each other in the London interbank market. The regulatory authority that oversees financial services firms and financial markets in the U.K. has announced that, after the end of 2021, it would no longer persuade or compel contributing banks to make rate submissions for purposes of determining the LIBOR rate. However, subsequent announcements by the FCA, the LIBOR administrator and other regulators indicate that it is possible that certain LIBOR tenors may continue beyond 2021. As a result, it is possible that commencing in 2022 (or on a later date, if a particular LIBOR tenor is expected to continue beyond the end of 2021), LIBOR may no longer be available or no longer deemed an appropriate reference rate upon which to determine the interest rate on or impacting certain derivatives and other instruments or investments comprising some of the Fund’s portfolio.

•

Investment Company Securities. Subject to the limitations set forth in the Investment Company Act of 1940, as amended (the “1940 Act”), or as otherwise permitted by the SEC, the Fund may acquire shares in other investment companies, including foreign investment companies and ETFs, which may be managed by the Adviser or its affiliates. The market value of the shares of other investment companies may differ from the NAV of the Fund. The shares of closed-end investment companies frequently trade at a discount to their NAV. As a shareholder in an investment company, the Fund would bear its ratable share of that entity’s expenses, including its investment advisory and administration fees. At the same time, the Fund would continue to pay its own advisory and administration fees and other expenses. As a result, the Fund and its shareholders, in effect, will be absorbing duplicate levels of fees with respect to investments in other investment companies.

•

Subsidiary Risk. The Subsidiary is not registered under the 1940 Act and is not subject to all the investor protections of the 1940 Act. Changes in the laws of the United States and/or the Cayman Islands could result in the inability of the Fund and/or the Subsidiary to operate as described herein and could adversely affect the Fund. By investing in the Subsidiary, the Fund is indirectly exposed to the risks associated with the Subsidiary’s investments.

•

Tax Risk. The Fund may seek to gain exposure to the commodity markets through investments in the Subsidiary. Historically, the Internal Revenue Service (“IRS”) has issued private letter rulings in which the IRS specifically concluded that income and gains from investments in commodity index-linked structured notes (the “Notes Rulings”) or a wholly-owned foreign subsidiary that invests in commodity-linked instruments are “qualifying income” for purposes of compliance with Subchapter M of the Internal Revenue Code of 1986, as amended (the “Code”). The Fund has not received such a private letter ruling, and is not able to rely on private letter rulings issued to other taxpayers. The IRS recently issued a revenue procedure, which states that the IRS will not in the future issue private letter rulings that would require a determination of whether an asset (such as a commodity index-linked note) is a “security” under the 1940 Act. In connection with issuing such revenue procedure, the IRS has revoked the Notes Rulings. The IRS also recently issued final regulations that would generally treat the Fund’s income inclusion with respect to the Subsidiary as qualifying income either if (A) there is a distribution out of the earnings and profits of the Subsidiary that are attributable to such income inclusion or (B) such inclusion is derived with respect to the Fund’s business of investing in stock,

securities, or currencies. The Fund intends to treat its income from the Subsidiary as qualifying income. No assurances can be provided that the IRS would not be able to successfully assert that the Fund’s income from such investments was not “qualifying income,” in which case the Fund would fail to qualify as a regulated investment company under Subchapter M of the Code if over 10% of its gross income was derived from these investments. If the Fund failed to qualify as a regulated investment company, it would be subject to federal and state income tax on all of its taxable income at regular corporate tax rates with no deduction for any distributions paid to shareholders, which would significantly adversely affect the returns to, and could cause substantial losses for, Fund shareholders. The Cayman Islands does not currently impose any income, corporate or capital gains tax, estate duty, inheritance tax, gift tax or withholding tax on the Subsidiary. If Cayman Islands law changes such that the Subsidiary must pay Cayman Islands taxes, Fund shareholders would likely suffer decreased investment returns.

•

Market and Geopolitical Risk. The value of your investment in the Fund is based on the values of the Fund’s investments, which may change due to economic and other events that affect markets generally, as well as those that affect particular regions, countries, industries, companies or governments. These events may be sudden and unexpected, and could adversely affect the liquidity of the Fund’s investments, which may in turn impact valuation, the Fund’s ability to sell securities and/or its ability to meet redemptions. The risks associated with these developments may be magnified if certain social, political, economic and other conditions and events (such as war, natural disasters, epidemics and pandemics, terrorism, conflicts and social unrest) adversely interrupt the global economy and financial markets. It is difficult to predict when events affecting the U.S. or global financial markets may occur, the effects that such events may have and the duration of those effects (which may last for extended periods). These events may negatively impact broad segments of businesses and populations and have a significant and rapid negative impact on the performance of the Fund’s investments, adversely affect and increase the volatility of the Fund’s share price and exacerbate pre-existing risks to the Fund.

•	Portfolio Turnover. Consistent with its investment policies, the Fund will purchase and sell securities without regard to the effect on portfolio turnover. Higher portfolio turnover will cause the Fund to incur additional transaction costs.

Shares of the Fund 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 Fund will achieve its investment objective, and you can lose money investing in this Fund.

Risk Not Insured Depository Institution [Text]

rr_RiskNotInsuredDepositoryInstitution

Shares of the Fund 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 Fund by showing changes in the Fund’s Class I shares’ performance from year-to-year and by showing how the Fund’s average annual returns for the past one, five and 10 year periods and since inception compare with those of broad measures 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 Fund’s returns in the table include the maximum applicable sales charge for Class A and Class C and assume you sold your shares at the end of each period (unless otherwise noted). The Fund’s past performance, before and after taxes, is not necessarily an indication of how the Fund will perform in the future. Updated performance information is available online at www.morganstanley.com/im or by calling toll-free 1-800-548-7786.

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

Performance Availability Phone [Text]

rr_PerformanceAvailabilityPhone

1-800-548-7786

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

www.morganstanley.com/im

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

The Fund’s past performance, before and after taxes, is not necessarily an indication of how the Fund will perform in the future.

Bar Chart [Heading]

rr_BarChartHeading

Annual Total Returns—Calendar Years

Performance Table Does Reflect Sales Loads

rr_PerformanceTableDoesReflectSalesLoads

The Fund’s returns in the table include the maximum applicable sales charge for Class A and Class C and assume you sold your shares at the end of each period (unless otherwise noted).

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

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 Fund 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 Fund’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 Fund shares been sold at the end of the relevant periods, as applicable.

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

High Quarter

06/30/20

13.92%

Low Quarter

03/31/20

-17.50%

Performance Table Heading

rr_PerformanceTableHeading

Average Annual Total Returns(for the calendar periods ended December 31, 2021)

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 Fund’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 Fund 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 Fund shares been sold at the end of the relevant periods, as applicable.

(MSIFT Global Strategist Portfolio - Classes I, A, L, C and IS) | (Global Strategist Portfolio) | MSCI All Country World Index (reflects no deduction for fees, expenses or taxes)

rr_ProspectusTable

rr_AverageAnnualReturnYear01

18.54%

^[1]

rr_AverageAnnualReturnYear05

14.40%

^[1]

rr_AverageAnnualReturnYear10

11.85%

^[1]

(MSIFT Global Strategist Portfolio - Classes I, A, L, C and IS) | (Global Strategist Portfolio) | Customized MSIM Global Allocation Index (reflects no deduction for fees, expenses or taxes)

rr_AverageAnnualReturnSinceInception

8.47%

^[1],[2]

rr_ProspectusTable

rr_AverageAnnualReturnYear01

8.78%

^[3]

rr_AverageAnnualReturnYear05

9.99%

^[3]

rr_AverageAnnualReturnYear10

7.58%

^[3]

(MSIFT Global Strategist Portfolio - Classes I, A, L, C and IS) | (Global Strategist Portfolio) | Lipper Flexible Portfolio Funds Index (reflects no deduction for taxes)

rr_AverageAnnualReturnSinceInception

^[3]

rr_ProspectusTable

rr_AverageAnnualReturnYear01

13.66%

^[4]

rr_AverageAnnualReturnYear05

11.21%

^[4]

rr_AverageAnnualReturnYear10

9.27%

^[4]

(MSIFT Global Strategist Portfolio - Classes I, A, L, C and IS) | (Global Strategist Portfolio) | Class I

rr_AverageAnnualReturnSinceInception

7.42%

^[2],[4]

Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price)

rr_ProspectusTable

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

rr_MaximumDeferredSalesChargeOverOther

none

rr_ManagementFeesOverAssets

0.45%

^[5]

rr_DistributionAndService12b1FeesOverAssets

none

rr_OtherExpensesOverAssets

0.31%

^[6]

rr_AcquiredFundFeesAndExpensesOverAssets

0.01%

rr_ExpensesOverAssets

0.77%

^[7]

Total Annual Fund Operating Expenses After Expense Reimbursement

rr_FeeWaiverOrReimbursementOverAssets

0.02%

^[7]

rr_NetExpensesOverAssets

0.75%

^[7]

rr_ExpenseExampleYear01

$ 77

rr_ExpenseExampleYear03

244

rr_ExpenseExampleYear05

426

rr_ExpenseExampleYear10

952

rr_ExpenseExampleNoRedemptionYear01

rr_ExpenseExampleNoRedemptionYear03

244

rr_ExpenseExampleNoRedemptionYear05

426

Highest Quarterly Return, Label

rr_ExpenseExampleNoRedemptionYear10

$ 952

Annual Return 2012

rr_AnnualReturn2012

15.85%

Annual Return 2013

rr_AnnualReturn2013

15.78%

Annual Return 2014

rr_AnnualReturn2014

3.13%

Annual Return 2015

rr_AnnualReturn2015

(6.15%)

Annual Return 2016

rr_AnnualReturn2016

5.58%

Annual Return 2017

rr_AnnualReturn2017

16.67%

Annual Return 2018

rr_AnnualReturn2018

(6.29%)

Annual Return 2019

rr_AnnualReturn2019

18.04%

Annual Return 2020

rr_AnnualReturn2020

11.53%

Annual Return 2021

rr_AnnualReturn2021

8.68%

rr_HighestQuarterlyReturnLabel

High Quarter

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

13.92%

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Jun. 30, 2020

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Low Quarter

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(17.50%)

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Mar. 31, 2020

rr_AverageAnnualReturnYear01

8.68%

rr_AverageAnnualReturnYear05

9.36%

rr_AverageAnnualReturnYear10

7.93%

(MSIFT Global Strategist Portfolio - Classes I, A, L, C and IS) | (Global Strategist Portfolio) | Class I | Return After Taxes on Distributions

rr_AverageAnnualReturnSinceInception

7.48%

rr_ProspectusTable

rr_AverageAnnualReturnYear01

5.72%

^[8]

rr_AverageAnnualReturnYear05

7.52%

^[8]

rr_AverageAnnualReturnYear10

6.45%

^[8]

(MSIFT Global Strategist Portfolio - Classes I, A, L, C and IS) | (Global Strategist Portfolio) | Class I | Return After Taxes on Distributions and Sale of Fund Shares

rr_AverageAnnualReturnSinceInception

5.69%

^[8]

rr_ProspectusTable

rr_AverageAnnualReturnYear01

5.45%

rr_AverageAnnualReturnYear05

6.86%

rr_AverageAnnualReturnYear10

5.90%

(MSIFT Global Strategist Portfolio - Classes I, A, L, C and IS) | (Global Strategist Portfolio) | Class A

rr_AverageAnnualReturnSinceInception

5.44%

Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price)

rr_ProspectusTable

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

5.25%

rr_MaximumDeferredSalesChargeOverOther

none

^[9]

rr_ManagementFeesOverAssets

0.45%

^[5]

rr_DistributionAndService12b1FeesOverAssets

0.25%

rr_OtherExpensesOverAssets

0.32%

^[6]

rr_AcquiredFundFeesAndExpensesOverAssets

0.01%

rr_ExpensesOverAssets

1.03%

^[7]

Total Annual Fund Operating Expenses After Expense Reimbursement

rr_FeeWaiverOrReimbursementOverAssets

none

^[7]

rr_NetExpensesOverAssets

1.03%

^[7]

Expenses Deferred Charges [Text Block]

rr_ExpensesDeferredChargesTextBlock

Investments in Class A shares that are not subject to any sales charges at the time of purchase are subject to a contingent deferred sales charge (“CDSC”) of 1.00% 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 Fund Shares” for further information about the CDSC waiver categories.

rr_ExpenseExampleYear01

$ 625

rr_ExpenseExampleYear03

836

rr_ExpenseExampleYear05

1,064

rr_ExpenseExampleYear10

1,718

rr_ExpenseExampleNoRedemptionYear01

625

rr_ExpenseExampleNoRedemptionYear03

836

rr_ExpenseExampleNoRedemptionYear05

1,064

rr_ExpenseExampleNoRedemptionYear10

$ 1,718

rr_AverageAnnualReturnYear01

2.67%

rr_AverageAnnualReturnYear05

7.86%

rr_AverageAnnualReturnYear10

7.02%

(MSIFT Global Strategist Portfolio - Classes I, A, L, C and IS) | (Global Strategist Portfolio) | Class L

rr_AverageAnnualReturnSinceInception

6.30%

Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price)

rr_ProspectusTable

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

rr_MaximumDeferredSalesChargeOverOther

none

rr_ManagementFeesOverAssets

0.45%

^[5]

rr_DistributionAndService12b1FeesOverAssets

0.75%

rr_OtherExpensesOverAssets

0.33%

^[6]

rr_AcquiredFundFeesAndExpensesOverAssets

0.01%

rr_ExpensesOverAssets

1.54%

^[7]

Total Annual Fund Operating Expenses After Expense Reimbursement

rr_FeeWaiverOrReimbursementOverAssets

none

^[7]

rr_NetExpensesOverAssets

1.54%

^[7]

rr_ExpenseExampleYear01

$ 157

rr_ExpenseExampleYear03

486

rr_ExpenseExampleYear05

839

rr_ExpenseExampleYear10

1,835

rr_ExpenseExampleNoRedemptionYear01

157

rr_ExpenseExampleNoRedemptionYear03

486

rr_ExpenseExampleNoRedemptionYear05

839

rr_ExpenseExampleNoRedemptionYear10

$ 1,835

rr_AverageAnnualReturnYear01

7.74%

rr_AverageAnnualReturnYear05

8.45%

rr_AverageAnnualReturnYear10

(MSIFT Global Strategist Portfolio - Classes I, A, L, C and IS) | (Global Strategist Portfolio) | Class C

rr_AverageAnnualReturnSinceInception

6.44%

Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price)

rr_ProspectusTable

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

rr_MaximumDeferredSalesChargeOverOther

1.00%

^[10]

rr_ManagementFeesOverAssets

0.45%

^[5]

rr_DistributionAndService12b1FeesOverAssets

1.00%

rr_OtherExpensesOverAssets

0.45%

^[6]

rr_AcquiredFundFeesAndExpensesOverAssets

0.01%

rr_ExpensesOverAssets

1.91%

^[7]

Total Annual Fund Operating Expenses After Expense Reimbursement

rr_FeeWaiverOrReimbursementOverAssets

0.06%

^[7]

rr_NetExpensesOverAssets

1.85%

^[7]

Expenses Deferred Charges [Text Block]

rr_ExpensesDeferredChargesTextBlock

The Class C CDSC is only applicable if you sell your shares within one year after the last day of the month of purchase. See “Shareholder Information—How To Redeem Fund Shares” for a complete discussion of the CDSC.

rr_ExpenseExampleYear01

$ 288

rr_ExpenseExampleYear03

594

rr_ExpenseExampleYear05

1,026

rr_ExpenseExampleYear10

1,999

rr_ExpenseExampleNoRedemptionYear01

188

rr_ExpenseExampleNoRedemptionYear03

594

rr_ExpenseExampleNoRedemptionYear05

1,026

rr_ExpenseExampleNoRedemptionYear10

$ 1,999

rr_AverageAnnualReturnYear01

6.47%

rr_AverageAnnualReturnYear05

8.14%

rr_AverageAnnualReturnYear10

(MSIFT Global Strategist Portfolio - Classes I, A, L, C and IS) | (Global Strategist Portfolio) | Class IS

rr_AverageAnnualReturnSinceInception

5.30%

Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price)

rr_ProspectusTable

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

rr_MaximumDeferredSalesChargeOverOther

none

rr_ManagementFeesOverAssets

0.45%

^[5]

rr_DistributionAndService12b1FeesOverAssets

none

rr_OtherExpensesOverAssets

0.23%

^[6]

rr_AcquiredFundFeesAndExpensesOverAssets

0.01%

rr_ExpensesOverAssets

0.69%

^[7]

Total Annual Fund Operating Expenses After Expense Reimbursement

rr_FeeWaiverOrReimbursementOverAssets

none

^[7]

rr_NetExpensesOverAssets

0.69%

^[7]

rr_ExpenseExampleYear01

$ 70

rr_ExpenseExampleYear03

221

rr_ExpenseExampleYear05

384

rr_ExpenseExampleYear10

859

rr_ExpenseExampleNoRedemptionYear01

rr_ExpenseExampleNoRedemptionYear03

221

rr_ExpenseExampleNoRedemptionYear05

384

rr_ExpenseExampleNoRedemptionYear10

$ 859

rr_AverageAnnualReturnYear01

8.67%

rr_AverageAnnualReturnYear05

9.38%

rr_AverageAnnualReturnYear10