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(MSIF - Opportunity Portfolios) | (Asia Opportunity Portfolio)  
Prospectus: rr_ProspectusTable  
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock
The Asia Opportunity Portfolio (the “Fund”) seeks long-term capital appreciation.
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 shares of the Fund and/or certain other Morgan Stanley Funds 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, amounts to $50,000 or more. More information about this combined purchase discount and other discounts is available from your authorized financial intermediary, on page 62 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 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 shares of the Fund and/or certain other Morgan Stanley Funds 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, amounts to $50,000 or more.
Expense Breakpoint, Minimum Investment Required [Amount] rr_ExpenseBreakpointMinimumInvestmentRequiredAmount $ 50,000
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 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 19%  of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 19.00%
Strategy [Heading] rr_StrategyHeading Principal Investment Strategies
Strategy Narrative [Text Block] rr_StrategyNarrativeTextBlock
Under normal market conditions, the Adviser seeks to achieve the Fund’s investment objective by investing primarily in equity securities of issuers located in Asia (excluding Japan), with capitalizations within the range of companies included in the MSCI All Country Asia ex Japan Index.
The Adviser emphasizes a bottom-up stock selection process, seeking attractive investments on an individual company basis. In selecting securities for investment, the Adviser seeks high quality established and emerging companies that the Adviser believes are undervalued at the time of purchase. Fundamental research drives the investment process. The Adviser typically favors companies it believes have sustainable competitive advantages that can be monetized through growth. The investment process integrates analysis of sustainability with respect to disruptive change, financial strength, environmental and social externalities and governance (also referred to as ESG). The Adviser typically focuses a significant portion of the Fund’s investments in a limited number of issuers, which may be in the same industry, sector or geographic region. The Adviser generally considers selling a portfolio holding when it determines that the holding no longer satisfies its investment criteria.
The Adviser views incorporating ESG-related potential risks and opportunities within the investment process as important to ensure long-term stewardship of capital. Over extended time horizons, the Adviser believes that ESG risks are more likely to materialize and externalities not borne by the company are more likely to be priced into the value of securities. Since ESG risks could potentially impact the risk and reward profile of investment opportunities, the Adviser typically engages company management in constructive discussions on a range of ESG issues the Adviser deems materially important.
The Fund may also invest in privately placed and restricted securities.
Under normal market conditions, at least 80% of the Fund’s assets will be invested in equity securities of issuers located in Asia, excluding Japan. This policy may be changed without shareholder approval; however, you would be notified upon 60 days’ notice in writing of any changes.
For purposes of maintaining exposure of at least 80% of the Fund’s assets to equity securities of issuers located in Asia, the Fund may also invest in American Depositary Receipts (“ADRs”), Global Depositary Receipts (“GDRs”) and other types of depositary receipts with respect to issuers located in Asia. The Fund may invest in China A-Shares (shares of publicly traded companies based in mainland China) listed and traded on the Shanghai Stock Exchange through the Shanghai-Hong Kong Stock Connect program, as well as China A-Shares listed and traded on the Shenzhen-Hong Kong Stock Connect program (collectively, “Stock Connect”).
The Fund invests primarily in securities of companies located in China, Hong Kong, India, Indonesia, Korea, Malaysia, the Philippines, Singapore, Taiwan and Thailand, but additional opportunities are also sought, whenever regulations permit, in any of the developed, emerging, and frontier countries and markets in the Asian region.
Risk [Heading] rr_RiskHeading Principal Risks
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 and five year periods and since inception compare with those of a broad measure of market performance. 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 1-800-869-6397.
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 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 and five year periods and since inception compare with those of a broad measure of market performance.
Performance Availability Phone [Text] rr_PerformanceAvailabilityPhone 1-800-869-6397
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress www.morganstanley.com/im
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture   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 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 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 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
03/31/19
25.05%
Low Quarter
03/31/22
-18.81%
Performance Table Heading rr_PerformanceTableHeading Average Annual Total Returns(for the calendar periods ended  December 31, 2024)
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 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.
(MSIF - Opportunity Portfolios) | (Asia Opportunity Portfolio) | Risk Not Insured Depository Institution [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock 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.
(MSIF - Opportunity Portfolios) | (Asia Opportunity Portfolio) | Risk Lose Money [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock There is no assurance that the Fund will achieve its investment objective, and you can lose money investing in this Fund.
(MSIF - Opportunity Portfolios) | (Asia Opportunity Portfolio) | Equity Securities [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock
•
Equity Securities. In general, prices of equity securities are more volatile than those of fixed-income securities. U.S. and foreign stock markets, and equity securities of individual issuers, have experienced periods of substantial price volatility in the past and it is possible that they will do so again in the future. The prices of equity securities fluctuate, sometimes rapidly or widely, 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, political and public health conditions.  During periods when equity securities experience heightened volatility, such as during periods of market, economic or financial uncertainty or distress, the Fund’s investments in equity securities are subject to heightened risks.
 
The value of equity securities declines in response to perceived or actual adverse changes in the economy, economic outlook or financial markets; deterioration in investor sentiment; inflation, interest rate, currency, and commodity price fluctuations; adverse geopolitical, social or environmental developments; issuer- and sector-specific considerations; unexpected trading activity among retail investors; and other factors. Market conditions affect certain types of equity securities to a greater extent than other types of equity securities. If the stock market declines, the value of the  Fund’s equity securities will also likely decline, which will result in a decrease in the value of your investment in the Fund. Although prices can rebound, there is no assurance that prices of the Fund’s equity securities will return to previous levels.
(MSIF - Opportunity Portfolios) | (Asia Opportunity Portfolio) | Active Management Risk [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock
•
Active Management Risk. In pursuing the Fund’s investment objective, the Adviser has considerable leeway in deciding which investments to buy, hold or sell on a day-to-day basis, and which trading strategies to use. For example, the Adviser, in its discretion, may determine to use some permitted trading strategies while not using others. The success or failure of such decisions will affect the Fund’s performance.
(MSIF - Opportunity Portfolios) | (Asia Opportunity Portfolio) | Focused Investing [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock
•
Focused Investing. Although the Fund is a diversified investment company under the Investment Company Act of 1940 (the “1940 Act”), the Fund typically invests a significant portion of its portfolio in a limited number of issuers, which may be in the same industry, sector or geographic region. As a result, the Fund will be more susceptible to risks associated with, and negative events affecting those issuers, industries, sectors or geographic regions, and a decline in the value of a particular instrument may cause the Fund’s overall value to be more volatile and decline to a greater degree than if the Fund were invested more widely.
(MSIF - Opportunity Portfolios) | (Asia Opportunity Portfolio) | Foreign and Emerging Market Securities [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock
•
Foreign and Emerging Market Securities. Investments in foreign markets entail special risks, such as currency, political (including geopolitical), economic and market risks and heightened risks, that may result in losses to the Fund. There also may be greater market volatility, less reliable financial information, less stringent investor protections and disclosure standards, higher transaction and custody costs and risks, 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 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 (including regional and global, military, or other conflicts), the imposition of economic sanctions against a particular country or countries, organizations, companies, entities and/or individuals, changes in international trading patterns, trade barriers (including tariffs) and other protectionist or retaliatory measures. Investments in foreign markets may also be adversely affected by governmental interventions or other 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 and decline in value in response to market developments or adverse investor perceptions, or become illiquid after purchase by the Fund, particularly during periods of market, economic, political and social 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.  Emerging market countries may be subject to increased potential for market manipulation and 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 market countries. 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 or other similar measures may be, and have been, imposed against certain countries, organizations, companies, entities and/or individuals. Economic sanctions and other similar measures could, among other things, effectively restrict or eliminate the Fund’s ability to purchase or sell securities (in the sanctioned country and other markets), negatively impact the value or liquidity of  the Fund’s investments, significantly delay or prevent the settlement of the Fund’s securities transactions, force the Fund to sell or otherwise dispose of investments at inopportune times or prices, or impair the Fund’s ability to meet its investment objective or invest in accordance with its investment strategies.
(MSIF - Opportunity Portfolios) | (Asia Opportunity Portfolio) | Market and Geopolitical Risk [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock
•
Market and Geopolitical Risk. The value of your investment in the Fund is based on the values of the Fund’s investments, which change due to economic, geopolitical and other events that affect the U.S. and global markets generally, as well as those that affect or are perceived or expected to affect particular regions, countries, industries, companies, issuers, sectors, asset classes or governments. These types of events may be sudden and unexpected, and could adversely affect the value (or income generated by) and liquidity of the Fund’s investments, which may in turn impact 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 or events, epidemics and pandemics, terrorism, conflicts, social unrest, recessions, inflation, interest rate changes, supply chain disruptions and the imposition of tariffs, trade barriers and other protectionist or retaliatory measures)  adversely interrupt or otherwise affect the global economy and financial markets. It is difficult to predict when events affecting the  U.S. or global financial markets or economies may occur, the effects that such events may have and the duration of those effects (which may last for extended periods). These types of events may negatively impact broad segments of businesses and populations and have a significant and rapid negative impact on the performance or value 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. The frequency and magnitude of resulting changes in the value of the Fund’s investments cannot be predicted.
(MSIF - Opportunity Portfolios) | (Asia Opportunity Portfolio) | Liquidity [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock
•
Liquidity. The Fund may make investments that are less liquid, illiquid or restricted or that may become illiquid or 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.  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 and may be unable to sell the security at all.
(MSIF - Opportunity Portfolios) | (Asia Opportunity Portfolio) | Asia Market [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock
•
Asia Market. The small size of securities markets and the low trading volume in many countries in Asia may lead to a lack of liquidity. The share prices of companies in the region tend to be volatile and there is a significant possibility of loss. Many of the countries in the region are developing, both politically and economically, and as a result companies in the region may be subject to risks like nationalization or other forms of government interference, and/or may be heavily reliant on only a few industries or commodities. Investments in the region may also be subject to currency risks, such as restrictions on the flow of money in and out of the country, extreme volatility relative to the U.S. dollar and devaluation, all of which could decrease the value of the Fund. Some countries in the region have previously experienced currency devaluations that resulted in higher interest rates, reductions in economic activity and drops in securities prices. In addition, because the Fund concentrates in a single region of the world, the Fund’s performance may be more volatile than that of a fund that invests globally. Consequently, if Asian securities fall out of favor, it may cause the Fund to underperform funds that do not concentrate in a single region of the world.
(MSIF - Opportunity Portfolios) | (Asia Opportunity Portfolio) | China Risk [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock
•
China Risk. Investments in securities of Chinese issuers, including A-shares, involve risks associated with investments in foreign markets as well as special considerations not typically associated with investments in the  U.S. securities markets. For example, the Chinese government has historically exercised substantial control over virtually every sector of the Chinese economy through administrative regulation and/or state ownership and actions of the Chinese central and local government authorities continue to have a substantial effect on economic conditions in China. In addition, the Chinese government has taken actions that influenced the prices at which certain goods may be sold, encouraged companies to invest or concentrate in particular industries, induced mergers between companies in certain industries and induced private companies to publicly offer their securities. Investments in China involve risk of a total loss due to government action or inaction or other adverse circumstances.
 
Additionally, the Chinese economy is export-driven and highly reliant on trade. Adverse changes to the economic conditions, trading policies and taxation of imports of its primary trading partners, such as the United States, Japan and South Korea, would adversely impact the Chinese economy and the Fund’s investments. Moreover, a slowdown in other significant economies of the
 
world, such as the United States, the European Union and certain Asian countries, may adversely affect economic growth or the value of investments in China. An economic downturn in China would adversely impact the Fund’s investments. In addition, certain securities are, or may in the future, become restricted, and/or sanctioned by the  U.S. government or other governments and the Fund may be forced to sell or unable to purchase or sell such restricted securities and incur a loss as a result.
 
Recent developments in relations between the  U.S., other trading partners and China have heightened concerns of increased tariffs and restrictions on trade between the two countries. An increase in tariffs or trade restrictions (and threats thereof) could lead to a significant reduction in international trade, which could have a negative impact on China’s export industry, Chinese issuers, the liquidity or price of the Fund’s direct or indirect investments in China and, therefore, the Fund.
 
These and other developments, including government actions, may result in significant  illiquidity risk or forced disposition for Chinese investments. The Chinese securities markets are emerging markets characterized by a relatively small number of equity issues and relatively low trading volume, resulting in decreased liquidity, greater price volatility (caused by, among other things, military, diplomatic, or trade conflicts), and potentially fewer investment opportunities for the Fund. The Fund’s investments in Chinese securities are also subject to additional risks associated with differing regulatory and audit requirements across the Chinese and  U.S. securities markets. Ongoing political tension between the People’s Republic of China and the Hong Kong Special Administrative Region may have impacts on the economy of Hong Kong, and these impacts remain uncertain.
 
Risks of Investing through Stock Connect. The Fund may invest in A-shares listed and traded through Stock Connect, or on such other stock exchanges in China which participate in Stock Connect from time to time or in the future. Trading through Stock Connect is subject to a number of restrictions that may affect the Fund’s investments and returns. Moreover, Stock Connect A-shares generally may not be sold, purchased or otherwise transferred other than through Stock Connect in accordance with applicable rules. The Stock Connect program is a relatively new program and may be subject to further interpretation and guidance. There can be no assurance as to the program’s continued existence or whether future developments regarding the program may restrict or adversely affect the Fund’s investments or returns. Because certain transactions through Stock Connect may not be subject to certain investor protection programs, the Fund may be exposed to the risks of default of the broker(s) they engage in their trading in China A Shares.
 
Variable Interest Entities. Chinese operating companies sometimes rely on variable interest entity (“VIE”) structures to raise capital from non-Chinese investors because of Chinese government limitations or prohibitions on direct foreign ownership in certain industries. In a VIE structure, a series of contractual arrangements are entered into between a holding company domiciled outside of China and a Chinese operating company or companies, which are intended to mimic direct ownership in the operating company, but in many cases these arrangements have not been tested in court and it is not clear that the contracts are enforceable or that the structures will otherwise work as intended. The offshore holding company, which is not a Chinese operating company, then issues exchange-traded shares that are sold to the public, including non-Chinese investors (such as the Fund). Shares of the offshore entity purchased by the Fund would not be equity ownership interests in the Chinese operating company and the Fund’s interest would be subject to legal, operational and other risks associated with the company’s use of the VIE structure. For example, at any time the Chinese government could determine that the contractual arrangements constituting part of the VIE structure are unenforceable or do not comply with applicable law or regulations, these laws or regulations could change or be interpreted differently in the future, and the Chinese government may with no advance notice otherwise intervene in or exert influence over VIE structures or the related Chinese operating companies. If any of these or similar risks or developments materialize, the Fund’s investment in the offshore entity may suddenly and significantly decline in value or become worthless because of, among other things, difficulty enforcing (or the inability to enforce) the contractual arrangements or materially adverse effects on the Chinese operating company’s performance. In these circumstances, the Fund could experience significant losses with no recourse available. From time to time, the Fund’s investments in U.S.-listed shell companies relying on VIE structures to consolidate China-based operations could be significant.
(MSIF - Opportunity Portfolios) | (Asia Opportunity Portfolio) | India Risk [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock
•
India Risk. To the extent that the Fund invests a substantial portion of its assets in Indian issuers, the value of the Fund’s assets may be adversely affected by political, economic, social and religious factors impacting Indian businesses and the Indian economy, changes in Indian law or regulations and the status of India’s relations with other countries. Indian government actions in the future could have a significant effect on the Indian economy, which could affect private sector companies and the Fund, market conditions, and prices and yields of securities in the Fund’s portfolio. To the extent the Fund invests a significant portion of its assets in Indian businesses and the Indian economy, factors that have an adverse impact on Indian businesses and the Indian economy may have a disproportionate impact on the Fund’s performance.
(MSIF - Opportunity Portfolios) | (Asia Opportunity Portfolio) | Consumer Discretionary Sector Risk [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock
•
Consumer Discretionary Sector Risk. To the extent that the Fund invests a substantial portion of its assets in the consumer discretionary sector,  the Fund will be particularly susceptible to the risks associated with companies operating in such sector(s). Companies in the consumer discretionary sector are subject to risks, including fluctuations in the performance of the overall domestic and international economy, shipment and supply chain disruptions, interest rate changes, currency exchange rates, increased competition and consumer confidence. Performance of such companies may also be adversely affected by factors such as reduced disposable household income, reduced consumer spending, and changing demographics and consumer tastes.
(MSIF - Opportunity Portfolios) | (Asia Opportunity Portfolio) | Financials Sector Risk [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock
•
Financials Sector Risk. To the extent the Fund invests a substantial portion of its assets in the financials sector, factors that have an adverse impact on this sector may have a disproportionate impact on the Fund’s performance. The financials sector can be affected by global and local economic conditions, such as the levels and liquidity of the global and local financial and asset markets, the absolute and relative level and volatility of interest rates and equity prices, investor sentiment, inflation, and the availability and cost of credit. Adverse developments in these conditions can have a greater adverse effect on the financials sector of an emerging market economy than on other industries of its economy. The enactment of new legislation or regulations, as well as changes in interpretation and enforcement of current laws, may affect the manner of operations and profitability of the financials sector.
(MSIF - Opportunity Portfolios) | (Asia Opportunity Portfolio) | MSCI All Country Asia ex Japan Net Index (reflects no deduction for fees, expenses or taxes)  
Prospectus: rr_ProspectusTable  
1 Year rr_AverageAnnualReturnYear01 11.96% [1]
5 Years rr_AverageAnnualReturnYear05 2.57% [1]
Since Inception rr_AverageAnnualReturnSinceInception 6.16% [1],[2]
(MSIF - Opportunity Portfolios) | (Asia Opportunity Portfolio) | Class I  
Prospectus: rr_ProspectusTable  
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum Deferred Sales Charge (as a percentage) rr_MaximumDeferredSalesChargeOverOther none
Redemption Fee (as a percentage of Amount Redeemed) rr_RedemptionFeeOverRedemption 2.00%
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.80% [3]
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets none
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 0.48% [4]
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 1.28% [5]
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets 0.18% [5]
Total Annual Fund Operating Expenses After Expense Reimbursement rr_NetExpensesOverAssets 1.10% [5]
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 112
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 388
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 685
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,529
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 112
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 388
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 685
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 $ 1,529
Annual Return 2016 rr_AnnualReturn2016 (1.34%)
Annual Return 2017 rr_AnnualReturn2017 76.82%
Annual Return 2018 rr_AnnualReturn2018 (13.65%)
Annual Return 2019 rr_AnnualReturn2019 44.74%
Annual Return 2020 rr_AnnualReturn2020 52.53%
Annual Return 2021 rr_AnnualReturn2021 (20.52%)
Annual Return 2022 rr_AnnualReturn2022 (22.01%)
Annual Return 2023 rr_AnnualReturn2023 (6.83%)
Annual Return 2024 rr_AnnualReturn2024 19.72%
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel High Quarter
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 25.05%
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Mar. 31, 2019
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel Low Quarter
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (18.81%)
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Mar. 31, 2022
1 Year rr_AverageAnnualReturnYear01 19.72%
5 Years rr_AverageAnnualReturnYear05 1.07%
Since Inception rr_AverageAnnualReturnSinceInception 9.72%
(MSIF - Opportunity Portfolios) | (Asia Opportunity Portfolio) | Class I | Return After Taxes on Distributions  
Prospectus: rr_ProspectusTable  
1 Year rr_AverageAnnualReturnYear01 19.16% [6]
5 Years rr_AverageAnnualReturnYear05 0.90% [6]
Since Inception rr_AverageAnnualReturnSinceInception 9.46% [6]
(MSIF - Opportunity Portfolios) | (Asia Opportunity Portfolio) | Class I | Return After Taxes on Distributions and Sale of Fund Shares  
Prospectus: rr_ProspectusTable  
1 Year rr_AverageAnnualReturnYear01 11.98%
5 Years rr_AverageAnnualReturnYear05 0.85%
Since Inception rr_AverageAnnualReturnSinceInception 7.91%
(MSIF - Opportunity Portfolios) | (Asia Opportunity Portfolio) | Class A  
Prospectus: rr_ProspectusTable  
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice 5.25%
Maximum Deferred Sales Charge (as a percentage) rr_MaximumDeferredSalesChargeOverOther none [7]
Redemption Fee (as a percentage of Amount Redeemed) rr_RedemptionFeeOverRedemption 2.00%
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.80% [3]
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets 0.25%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 0.49% [4]
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 1.54% [5]
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets 0.09% [5]
Total Annual Fund Operating Expenses After Expense Reimbursement rr_NetExpensesOverAssets 1.45% [5]
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 12 months, except for certain specific circumstances. See “Shareholder Information—How To Redeem Fund Shares” for further information about the CDSC waiver categories.
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 665
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 978
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 1,312
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 2,256
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 665
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 978
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 1,312
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 $ 2,256
1 Year rr_AverageAnnualReturnYear01 13.12%
5 Years rr_AverageAnnualReturnYear05 (0.30%)
Since Inception rr_AverageAnnualReturnSinceInception 8.73%
(MSIF - Opportunity Portfolios) | (Asia Opportunity Portfolio) | Class C  
Prospectus: rr_ProspectusTable  
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum Deferred Sales Charge (as a percentage) rr_MaximumDeferredSalesChargeOverOther 1.00% [8]
Redemption Fee (as a percentage of Amount Redeemed) rr_RedemptionFeeOverRedemption 2.00%
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.80% [3]
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets 1.00%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 0.49% [4]
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 2.29% [5]
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets 0.09% [5]
Total Annual Fund Operating Expenses After Expense Reimbursement rr_NetExpensesOverAssets 2.20% [5]
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.
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 323
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 707
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 1,217
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 2,431
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 223
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 707
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 1,217
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 $ 2,431
1 Year rr_AverageAnnualReturnYear01 17.47%
5 Years rr_AverageAnnualReturnYear05 0.04%
Since Inception rr_AverageAnnualReturnSinceInception 8.66% [9]
(MSIF - Opportunity Portfolios) | (Asia Opportunity Portfolio) | Class R6  
Prospectus: rr_ProspectusTable  
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum Deferred Sales Charge (as a percentage) rr_MaximumDeferredSalesChargeOverOther none
Redemption Fee (as a percentage of Amount Redeemed) rr_RedemptionFeeOverRedemption 2.00%
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.80% [3]
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets none
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 0.48% [4]
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 1.28% [5]
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets 0.23% [5]
Total Annual Fund Operating Expenses After Expense Reimbursement rr_NetExpensesOverAssets 1.05% [5]
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 107
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 383
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 680
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,525
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 107
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 383
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 680
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 $ 1,525
1 Year rr_AverageAnnualReturnYear01 19.90%
5 Years rr_AverageAnnualReturnYear05 1.14%
Since Inception rr_AverageAnnualReturnSinceInception 9.79%
(MSIF - Opportunity Portfolios) | (Developing Opportunity Portfolio)  
Prospectus: rr_ProspectusTable  
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock
The Developing Opportunity Portfolio (the “Fund”) seeks long-term capital appreciation.
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 shares of the Fund and/or certain other Morgan Stanley Funds 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, amounts to $50,000 or more. More information about this combined purchase discount and other discounts is available from your authorized financial intermediary, on page 62 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 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 shares of the Fund and/or certain other Morgan Stanley Funds 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, amounts to $50,000 or more.
Expense Breakpoint, Minimum Investment Required [Amount] rr_ExpenseBreakpointMinimumInvestmentRequiredAmount $ 50,000
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 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 29%  of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 29.00%
Strategy [Heading] rr_StrategyHeading Principal Investment Strategies
Strategy Narrative [Text Block] rr_StrategyNarrativeTextBlock
Under normal market conditions, the Adviser seeks to achieve the Fund’s investment objective by investing primarily in equity securities of issuers located or operating in developing or emerging market countries, with capitalizations within the range of companies included in the MSCI Emerging Markets Net Index. For purposes of this prospectus, “developing markets,” “developing market countries,” “emerging markets” and “emerging market countries” and similar terms are used interchangeably but refer to the same underlying markets and countries.
The Adviser emphasizes a bottom-up stock selection process, seeking attractive investments on an individual company basis. In  selecting securities for investment, the Adviser seeks high quality companies within developing markets that the Adviser believes are  undervalued at the time of purchase. Fundamental research drives the investment process. The Adviser typically favors companies it believes have sustainable competitive advantages that  can be monetized through growth. The investment process integrates analysis of sustainability with respect to disruptive change, financial strength, environmental and social externalities and governance (also referred to as ESG). The Adviser typically focuses a significant portion of the Fund’s investments in a limited number of issuers, which may be in the same industry, sector or geographic region. The Adviser generally considers selling a portfolio holding when it determines that the holding no longer satisfies its investment criteria.    
The Adviser views incorporating ESG-related potential risks and opportunities within the investment process as important to ensure long-term stewardship of capital. Over extended time horizons, the Adviser believes that ESG risks are more likely to materialize and externalities not borne by the company are more likely to be priced into the value of securities. Since ESG risks could potentially impact the risk and reward profile of investment opportunities, the Adviser typically engages company management in constructive discussions on a range of ESG issues the Adviser deems materially important.
The Fund may also invest in privately placed and restricted securities.
Under normal market conditions, at least 80% of the Fund’s assets will be invested in equity securities of issuers located or operating in developing markets. This policy may be changed without shareholder approval; however, you would be notified upon 60 days’ notice in writing of any changes.  
For purposes of the Fund’s 80% policy, developing market countries will include frontier emerging market countries. The term “frontier emerging markets” refers to those emerging market countries outside the “mainstream” emerging markets, whose capital markets have traditionally been difficult for foreign investors to enter or are in early stages of capital market and/or economic development. The countries that comprise frontier emerging markets may change from time to time.
For purposes of maintaining exposure of at least 80% of the Fund’s assets to equity securities of issuers located or operating in developing markets, the Fund may  also invest in  American Depositary Receipts (“ADRs”), Global Depositary Receipts (“GDRs”) and other types of depositary receipts with respect to issuers located or operating in developing markets.  The Fund may invest in China A-Shares (shares of publicly traded companies based in mainland China) listed and traded on the Shanghai Stock Exchange through the Shanghai-Hong Kong Stock Connect program, as well as China A-Shares listed and traded on the Shenzhen-Hong Kong Stock Connect program (collectively, “Stock Connect”).
Risk [Heading] rr_RiskHeading Principal Risks
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 year period and since inception compare with those of a broad measure of market performance. 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 1-800-869-6397.
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 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 year period and since inception compare with those of a broad measure of market performance.
Performance Availability Phone [Text] rr_PerformanceAvailabilityPhone 1-800-869-6397
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 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 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 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
09/30/24
14.06%
Low Quarter
03/31/22
-18.91%
Performance Table Heading rr_PerformanceTableHeading Average Annual Total Returns (for the calendar periods ended  December 31, 2024)
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 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.
(MSIF - Opportunity Portfolios) | (Developing Opportunity Portfolio) | Risk Not Insured Depository Institution [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock 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.
(MSIF - Opportunity Portfolios) | (Developing Opportunity Portfolio) | Risk Lose Money [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock There is no assurance that the Fund will achieve its investment objective, and you can lose money investing in this Fund.
(MSIF - Opportunity Portfolios) | (Developing Opportunity Portfolio) | Equity Securities [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock
•
Equity Securities. In general, prices of equity securities are more volatile than those of fixed-income securities. U.S. and foreign stock markets, and equity securities of individual issuers, have experienced periods of substantial price volatility in the past and it is possible that they will do so again in the future. The prices of equity securities fluctuate, sometimes rapidly or widely, 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, political and public health conditions.  During periods when equity securities experience heightened volatility, such as during periods of market, economic or financial uncertainty or distress, the Fund’s investments in equity securities are subject to heightened risks.
 
The value of equity securities declines in response to perceived or actual adverse changes in the economy, economic outlook or financial markets; deterioration in investor sentiment; inflation, interest rate, currency, and commodity price fluctuations; adverse geopolitical, social or environmental developments; issuer- and sector-specific considerations; unexpected trading activity among retail investors; and other factors. Market conditions affect certain types of equity securities to a greater extent than other types of equity securities. If the stock market declines, the value of the  Fund’s equity securities will also likely decline, which will result in a decrease in the value of your investment in the Fund. Although prices can rebound, there is no assurance that prices of the Fund’s equity securities will return to previous levels.
(MSIF - Opportunity Portfolios) | (Developing Opportunity Portfolio) | Active Management Risk [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock
•
Active Management Risk. In pursuing the Fund’s investment objective, the Adviser has considerable leeway in deciding which investments to buy, hold or sell on a day-to-day basis, and which trading strategies to use. For example, the Adviser, in its discretion, may determine to use some permitted trading strategies while not using others. The success or failure of such decisions will affect the Fund’s performance.
(MSIF - Opportunity Portfolios) | (Developing Opportunity Portfolio) | Focused Investing [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock
•
Focused Investing. Although the Fund is a diversified investment company under the Investment Company Act of 1940 (the “1940 Act”), the Fund typically invests a significant portion of its portfolio in a limited number of issuers, which may be in the same industry, sector or geographic region. As a result, the Fund will be more susceptible to risks associated with, and negative events affecting those issuers, industries, sectors or geographic regions, and a decline in the value of a particular instrument may cause the Fund’s overall value to be more volatile and decline to a greater degree than if the Fund were invested more widely.
(MSIF - Opportunity Portfolios) | (Developing Opportunity Portfolio) | Foreign and Emerging Market Securities [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock
•
Foreign and Emerging Market Securities. Investments in foreign markets entail special risks, such as currency, political (including geopolitical), economic and market risks and heightened risks, that may result in losses to the Fund. There also may be greater market volatility, less reliable financial information, less stringent investor protections and disclosure standards, higher transaction and custody costs and risks, 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 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 (including regional and global, military, or other conflicts), the imposition of economic sanctions against a particular country or countries, organizations, companies, entities and/or individuals, changes in international trading patterns, trade barriers (including tariffs) and other protectionist or retaliatory measures. Investments in foreign markets may also be adversely affected by governmental interventions or other 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 and decline in value in response to market developments or adverse investor perceptions, or become illiquid after purchase by the Fund, particularly during periods of market, economic, political and social 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.  Emerging market countries may be subject to increased potential
for market manipulation and 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 market countries. 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 or other similar measures may be, and have been, imposed against certain countries, organizations, companies, entities and/or individuals. Economic sanctions and other similar measures could, among other things, effectively restrict or eliminate the Fund’s ability to purchase or sell securities (in the sanctioned country and other markets), negatively impact the value or liquidity of  the Fund’s investments, significantly delay or prevent the settlement of the Fund’s securities transactions, force the Fund to sell or otherwise dispose of investments at inopportune times or prices, or impair the Fund’s ability to meet its investment objective or invest in accordance with its investment strategies.
(MSIF - Opportunity Portfolios) | (Developing Opportunity Portfolio) | Market and Geopolitical Risk [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock
•
Market and Geopolitical Risk. The value of your investment in the Fund is based on the values of the Fund’s investments, which change due to economic, geopolitical and other events that affect the U.S. and global markets generally, as well as those that affect or are perceived or expected to affect particular regions, countries, industries, companies, issuers, sectors, asset classes or governments. These types of events may be sudden and unexpected, and could adversely affect the value (or income generated by) and liquidity of the Fund’s investments, which may in turn impact 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 or events, epidemics and pandemics, terrorism, conflicts, social unrest, recessions, inflation, interest rate changes, supply chain disruptions and the imposition of tariffs, trade barriers and other protectionist or retaliatory measures)  adversely interrupt or otherwise affect the global economy and financial markets. It is difficult to predict when events affecting the  U.S. or global financial markets or economies may occur, the effects that such events may have and the duration of those effects (which may last for extended periods). These types of events may negatively impact broad segments of businesses and populations and have a significant and rapid negative impact on the performance or value 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. The frequency and magnitude of resulting changes in the value of the Fund’s investments cannot be predicted.
(MSIF - Opportunity Portfolios) | (Developing Opportunity Portfolio) | Liquidity [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock
•
Liquidity. The Fund may make investments that are less liquid, illiquid or restricted or that may become illiquid or 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.  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 and may be unable to sell the security at all.
(MSIF - Opportunity Portfolios) | (Developing Opportunity Portfolio) | China Risk [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock
•
China Risk. Investments in securities of Chinese issuers, including A-shares, involve risks associated with investments in foreign markets as well as special considerations not typically associated with investments in the  U.S. securities markets. For example, the Chinese government has historically exercised substantial control over virtually every sector of the Chinese economy through administrative regulation and/or state ownership and actions of the Chinese central and local government authorities continue to have a substantial effect on economic conditions in China. In addition, the Chinese government has taken actions that influenced the prices at which certain goods may be sold, encouraged companies to invest or concentrate in particular industries, induced mergers between companies in certain industries and induced private companies to publicly offer their securities. Investments in China involve risk of a total loss due to government action or inaction or other adverse circumstances.
 
Additionally, the Chinese economy is export-driven and highly reliant on trade. Adverse changes to the economic conditions, trading policies and taxation of imports of its primary trading partners, such as the United States, Japan and South Korea, would adversely impact the Chinese economy and the Fund’s investments. Moreover, a slowdown in other significant economies of the world, such as the United States, the European Union and certain Asian countries, may adversely affect economic growth or the value of investments in China. An economic downturn in China would adversely impact the Fund’s investments. In addition, certain securities are, or may in the future, become restricted, and/or sanctioned by the  U.S. government or other governments and the Fund may be forced to sell or unable to purchase or sell such restricted securities and incur a loss as a result.
 
Recent developments in relations between the  U.S., other trading partners and China have heightened concerns of increased tariffs and restrictions on trade between the two countries. An increase in tariffs or trade restrictions (and threats thereof) could lead to a
 
significant reduction in international trade, which could have a negative impact on China’s export industry, Chinese issuers, the liquidity or price of the Fund’s direct or indirect investments in China and, therefore, the Fund.
 
These and other developments, including government actions, may result in significant  illiquidity risk or forced disposition for Chinese investments. The Chinese securities markets are emerging markets characterized by a relatively small number of equity issues and relatively low trading volume, resulting in decreased liquidity, greater price volatility (caused by, among other things, military, diplomatic, or trade conflicts), and potentially fewer investment opportunities for the Fund. The Fund’s investments in Chinese securities are also subject to additional risks associated with differing regulatory and audit requirements across the Chinese and  U.S. securities markets. Ongoing political tension between the People’s Republic of China and the Hong Kong Special Administrative Region may have impacts on the economy of Hong Kong, and these impacts remain uncertain.
 
Risks of Investing through Stock Connect. The Fund may invest in A-shares listed and traded through Stock Connect, or on such other stock exchanges in China which participate in Stock Connect from time to time or in the future. Trading through Stock Connect is subject to a number of restrictions that may affect the Fund’s investments and returns. Moreover, Stock Connect A-shares generally may not be sold, purchased or otherwise transferred other than through Stock Connect in accordance with applicable rules. The Stock Connect program is a relatively new program and may be subject to further interpretation and guidance. There can be no assurance as to the program’s continued existence or whether future developments regarding the program may restrict or adversely affect the Fund’s investments or returns. Because certain transactions through Stock Connect may not be subject to certain investor protection programs, the Fund may be exposed to the risks of default of the broker(s) they engage in their trading in China A Shares.
 
Variable Interest Entities. Chinese operating companies sometimes rely on variable interest entity (“VIE”) structures to raise capital from non-Chinese investors because of Chinese government limitations or prohibitions on direct foreign ownership in certain industries. In a VIE structure, a series of contractual arrangements are entered into between a holding company domiciled outside of China and a Chinese operating company or companies, which are intended to mimic direct ownership in the operating company, but in many cases these arrangements have not been tested in court and it is not clear that the contracts are enforceable or that the structures will otherwise work as intended. The offshore holding company, which is not a Chinese operating company, then issues exchange-traded shares that are sold to the public, including non-Chinese investors (such as the Fund). Shares of the offshore entity purchased by the Fund would not be equity ownership interests in the Chinese operating company and the Fund’s interest would be subject to legal, operational and other risks associated with the company’s use of the VIE structure. For example, at any time the Chinese government could determine that the contractual arrangements constituting part of the VIE structure are unenforceable or do not comply with applicable law or regulations, these laws or regulations could change or be interpreted differently in the future, and the Chinese government may with no advance notice otherwise intervene in or exert influence over VIE structures or the related Chinese operating companies. If any of these or similar risks or developments materialize, the Fund’s investment in the offshore entity may suddenly and significantly decline in value or become worthless because of, among other things, difficulty enforcing (or the inability to enforce) the contractual arrangements or materially adverse effects on the Chinese operating company’s performance. In these circumstances, the Fund could experience significant losses with no recourse available. From time to time, the Fund’s investments in U.S.-listed shell companies relying on VIE structures to consolidate China-based operations could be significant.
(MSIF - Opportunity Portfolios) | (Developing Opportunity Portfolio) | India Risk [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock
•
India Risk. To the extent that the Fund invests a substantial portion of its assets in Indian issuers, the value of the Fund’s assets may be adversely affected by political, economic, social and religious factors impacting Indian businesses and the Indian economy, changes in Indian law or regulations and the status of India’s relations with other countries. Indian government actions in the future could have a significant effect on the Indian economy, which could affect private sector companies and the Fund, market conditions, and prices and yields of securities in the Fund’s portfolio. To the extent the Fund invests a significant portion of its assets in Indian businesses and the Indian economy, factors that have an adverse impact on Indian businesses and the Indian economy may have a disproportionate impact on the Fund’s performance.
(MSIF - Opportunity Portfolios) | (Developing Opportunity Portfolio) | Consumer Discretionary Sector Risk [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock
•
Consumer Discretionary Sector Risk. To the extent that the Fund invests a substantial portion of its assets in the consumer discretionary sector,  the Fund will be particularly susceptible to the risks associated with companies operating in such sector(s). Companies in the consumer discretionary sector are subject to risks, including fluctuations in the performance of the overall domestic and international economy, shipment and supply chain disruptions, interest rate changes, currency exchange rates, increased competition and consumer confidence. Performance of such companies may also be adversely affected by factors such as reduced disposable household income, reduced consumer spending, and changing demographics and consumer tastes.
(MSIF - Opportunity Portfolios) | (Developing Opportunity Portfolio) | Financials Sector Risk [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock
•
Financials Sector Risk. To the extent the Fund invests a substantial portion of its assets in the financials sector, factors that have an adverse impact on this sector may have a disproportionate impact on the Fund’s performance. The financials sector can be affected by global and local economic conditions, such as the levels and liquidity of the global and local financial and asset markets, the absolute and relative level and volatility of interest rates and equity prices, investor sentiment, inflation, and the availability and cost of credit. Adverse developments in these conditions can have a greater adverse effect on the financials sector of an emerging market economy than on other industries of its economy. The enactment of new legislation or regulations, as well as changes in interpretation and enforcement of current laws, may affect the manner of operations and profitability of the financials sector.
(MSIF - Opportunity Portfolios) | (Developing Opportunity Portfolio) | Frontier Emerging Market Securities [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock
•
Frontier Emerging Market Securities.  Investing in the securities of issuers operating in frontier emerging markets involves a high degree of risk and special considerations not typically associated with investing in the securities of other foreign or U.S. issuers. In addition, the risks associated with investing in the securities of issuers operating in emerging market countries are magnified when investing in frontier emerging market countries. These types of investments could be affected by factors not usually associated with investments in U.S. issuers, including risks associated with expropriation and/or nationalization, political or social instability, pervasiveness of corruption and crime, armed conflict, the impact on the economy of civil war, religious or ethnic unrest and the withdrawal or non-renewal of any license enabling the Fund to trade in securities of a particular country, confiscatory taxation, restrictions on transfers of assets, lack of uniform accounting, auditing and financial reporting standards, less publicly available financial and other information, less stringent investor protections and disclosure standards, diplomatic development which could affect U.S. investments in those countries and potential difficulties in enforcing contractual obligations. These risks and special considerations make investments in companies operating in frontier emerging market countries highly speculative in nature and, accordingly, an investment in the Fund must be viewed as highly speculative in nature and may not be suitable for an investor who is not able to afford the loss of his or her entire investment. To the extent that the Fund invests a significant percentage of its assets in a single frontier emerging market country, the Fund will be subject to heightened risk associated with investing in frontier emerging market countries and additional risks associated with that particular country.  A government of a frontier emerging market country may limit or cause delay in the convertibility or repatriation of its currency and therefore could 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. From time to time, certain of the companies in which the Fund expects to invest may operate in, or have dealings with, countries subject to sanctions or embargoes imposed by the U.S. Government and the United Nations and/or countries identified by the U.S. Government as state sponsors of terrorism. A company may suffer damage to its reputation if it is identified as such a company and, as an investor in such companies, the Fund will be indirectly subject to those risks. Certain frontier 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 frontier markets countries. In addition, a substantial portion of 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 could reduce or preclude the opportunity for gain if the value of the currency moves 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.
(MSIF - Opportunity Portfolios) | (Developing Opportunity Portfolio) | MSCI Emerging Markets Net Index (reflects no deduction for fees, expenses or taxes)  
Prospectus: rr_ProspectusTable  
1 Year rr_AverageAnnualReturnYear01 7.50% [10]
Since Inception rr_AverageAnnualReturnSinceInception 1.89% [10],[11]
(MSIF - Opportunity Portfolios) | (Developing Opportunity Portfolio) | Class I  
Prospectus: rr_ProspectusTable  
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum Deferred Sales Charge (as a percentage) rr_MaximumDeferredSalesChargeOverOther none
Redemption Fee (as a percentage of Amount Redeemed) rr_RedemptionFeeOverRedemption 2.00%
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.90% [12]
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets none
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 1.10% [13]
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 2.00% [14]
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets 0.85% [14]
Total Annual Fund Operating Expenses After Expense Reimbursement rr_NetExpensesOverAssets 1.15% [14]
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 117
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 545
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 999
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 2,259
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 117
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 545
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 999
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 $ 2,259
Annual Return 2021 rr_AnnualReturn2021 (18.69%)
Annual Return 2022 rr_AnnualReturn2022 (30.36%)
Annual Return 2023 rr_AnnualReturn2023 5.36%
Annual Return 2024 rr_AnnualReturn2024 16.79%
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel High Quarter
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 14.06%
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Sep. 30, 2024
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel Low Quarter
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (18.91%)
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Mar. 31, 2022
1 Year rr_AverageAnnualReturnYear01 16.79%
Since Inception rr_AverageAnnualReturnSinceInception 0.21%
(MSIF - Opportunity Portfolios) | (Developing Opportunity Portfolio) | Class I | Return After Taxes on Distributions  
Prospectus: rr_ProspectusTable  
1 Year rr_AverageAnnualReturnYear01 16.56% [15]
Since Inception rr_AverageAnnualReturnSinceInception 0.17% [15]
(MSIF - Opportunity Portfolios) | (Developing Opportunity Portfolio) | Class I | Return After Taxes on Distributions and Sale of Fund Shares  
Prospectus: rr_ProspectusTable  
1 Year rr_AverageAnnualReturnYear01 10.06%
Since Inception rr_AverageAnnualReturnSinceInception 0.15%
(MSIF - Opportunity Portfolios) | (Developing Opportunity Portfolio) | Class A  
Prospectus: rr_ProspectusTable  
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice 5.25%
Maximum Deferred Sales Charge (as a percentage) rr_MaximumDeferredSalesChargeOverOther none [16]
Redemption Fee (as a percentage of Amount Redeemed) rr_RedemptionFeeOverRedemption 2.00%
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.90% [12]
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets 0.25%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 1.17% [13]
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 2.32% [14]
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets 0.82% [14]
Total Annual Fund Operating Expenses After Expense Reimbursement rr_NetExpensesOverAssets 1.50% [14]
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 12 months, except for certain specific circumstances. See “Shareholder Information—How To Redeem Fund Shares” for further information about the CDSC waiver categories.
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 670
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 1,137
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 1,630
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 2,982
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 670
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 1,137
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 1,630
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 $ 2,982
1 Year rr_AverageAnnualReturnYear01 10.33%
Since Inception rr_AverageAnnualReturnSinceInception (1.19%)
(MSIF - Opportunity Portfolios) | (Developing Opportunity Portfolio) | Class C  
Prospectus: rr_ProspectusTable  
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum Deferred Sales Charge (as a percentage) rr_MaximumDeferredSalesChargeOverOther 1.00% [17]
Redemption Fee (as a percentage of Amount Redeemed) rr_RedemptionFeeOverRedemption 2.00%
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.90% [12]
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets 1.00%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 1.20% [13]
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 3.10% [14]
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets 0.85% [14]
Total Annual Fund Operating Expenses After Expense Reimbursement rr_NetExpensesOverAssets 2.25% [14]
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.
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 328
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 877
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 1,551
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 3,170
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 228
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 877
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 1,551
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 $ 3,170
1 Year rr_AverageAnnualReturnYear01 14.56%
Since Inception rr_AverageAnnualReturnSinceInception (0.88%)
(MSIF - Opportunity Portfolios) | (Developing Opportunity Portfolio) | Class R6  
Prospectus: rr_ProspectusTable  
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum Deferred Sales Charge (as a percentage) rr_MaximumDeferredSalesChargeOverOther none
Redemption Fee (as a percentage of Amount Redeemed) rr_RedemptionFeeOverRedemption 2.00%
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.90% [12]
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets none
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 24.59% [13]
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 25.49% [14]
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets 24.39% [14]
Total Annual Fund Operating Expenses After Expense Reimbursement rr_NetExpensesOverAssets 1.10% [14]
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 112
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 4,379
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 7,077
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 10,240
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 112
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 4,379
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 7,077
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 $ 10,240
1 Year rr_AverageAnnualReturnYear01 16.81%
Since Inception rr_AverageAnnualReturnSinceInception 0.26%
(MSIF - Opportunity Portfolios) | (Global Opportunity Portfolio)  
Prospectus: rr_ProspectusTable  
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock
The Global Opportunity Portfolio (the “Fund”) seeks long-term capital appreciation.
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 shares of the Fund and/or certain other Morgan Stanley Funds 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, amounts to $50,000 or more. More information about this combined purchase discount and other discounts is available from your authorized financial intermediary, on page 62 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 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 shares of the Fund and/or certain other Morgan Stanley Funds 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, amounts to $50,000 or more.
Expense Breakpoint, Minimum Investment Required [Amount] rr_ExpenseBreakpointMinimumInvestmentRequiredAmount $ 50,000
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 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 19%  of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 19.00%
Strategy [Heading] rr_StrategyHeading Principal Investment Strategies
Strategy Narrative [Text Block] rr_StrategyNarrativeTextBlock
Under normal market conditions, the Adviser seeks to achieve the Fund’s investment objective by investing primarily in established and emerging companies located throughout the world, with capitalizations within the range of companies included in the MSCI All Country World Index.
The Adviser emphasizes a bottom-up stock selection process, seeking attractive investments on an individual company basis. In selecting securities for investment, the Adviser seeks high quality established and emerging companies that the Adviser believes are undervalued at the time of purchase. Fundamental research drives the investment process. The Adviser typically favors companies it believes have sustainable competitive advantages that can be monetized through growth. The investment process integrates analysis of sustainability with respect to disruptive change, financial strength, environmental and social externalities and governance (also referred to as ESG). The Adviser typically focuses a significant portion of the Fund’s investments in a limited number of issuers, which may be in the same industry, sector or geographic region. The Adviser generally considers selling a portfolio holding when it determines that the holding no longer satisfies its investment criteria.
The Adviser views incorporating ESG-related potential risks and opportunities within the investment process as important to ensure long-term stewardship of capital. Over extended time horizons, the Adviser believes that ESG risks are more likely to materialize and externalities not borne by the company are more likely to be priced into the value of securities. Since ESG risks could potentially impact the risk and reward profile of investment opportunities, the Adviser typically engages company management in constructive discussions on a range of ESG issues the Adviser deems materially important.
The Fund may invest in China A-Shares (shares of publicly traded companies based in mainland China) listed and traded on the Shanghai Stock Exchange through the Shanghai-Hong Kong Stock Connect program, as well as China A-Shares listed and traded on the Shenzhen-Hong Kong Stock Connect program (collectively, “Stock Connect”).
The Fund may also invest in American Depositary Receipts (“ADRs”), Global Depositary Receipts (“GDRs”) and other types of depositary receipts with respect to issuers located or operating outside of the United States. The Fund may invest in equity securities. The Fund may also invest in privately placed and restricted securities.
Risk [Heading] rr_RiskHeading Principal Risks
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Performance Information
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
Pursuant to an agreement and plan of reorganization between the Company, on behalf of the Fund, and Van Kampen Equity Trust, on behalf of the Van Kampen Global Growth Fund (the “Predecessor Fund”), on May 21, 2010 the Fund acquired substantially all of the assets and substantially all of the liabilities of the Predecessor Fund in exchange for Class I and Class L shares of the Fund (the “Reorganization”). Pursuant to the Reorganization, Class C and Class I shareholders of the Predecessor Fund received Class L and Class I shares, respectively, of the Fund. As a result of the Reorganization, the Fund is the accounting successor of the Predecessor Fund. The historical performance information shown below reflects, for the period prior to the Reorganization, the historical performance of the Class C and Class I shares of the Predecessor Fund.
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 ten year periods and since inception compare with those of a broad measure of market performance. 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 1-800-869-6397.
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 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 ten year periods and since inception compare with those of a broad measure of market performance.
Performance Availability Phone [Text] rr_PerformanceAvailabilityPhone 1-800-869-6397
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 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 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 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
31.66%
Low Quarter
06/30/22
-27.33%
Performance Table Heading rr_PerformanceTableHeading Average Annual Total Returns1(for the calendar periods ended  December 31, 2024) [18]
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 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.
(MSIF - Opportunity Portfolios) | (Global Opportunity Portfolio) | Risk Not Insured Depository Institution [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock 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.
(MSIF - Opportunity Portfolios) | (Global Opportunity Portfolio) | Risk Lose Money [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock There is no assurance that the Fund will achieve its investment objective, and you can lose money investing in this Fund.
(MSIF - Opportunity Portfolios) | (Global Opportunity Portfolio) | Equity Securities [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock
•
Equity Securities. In general, prices of equity securities are more volatile than those of fixed-income securities. U.S. and foreign stock markets, and equity securities of individual issuers, have experienced periods of substantial price volatility in the past and it is possible that they will do so again in the future. The prices of equity securities fluctuate, sometimes rapidly or widely, 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, political and public health conditions.  During periods when equity securities experience heightened volatility, such as during periods of market, economic or financial uncertainty or distress, the Fund’s investments in equity securities are subject to heightened risks.
 
The value of equity securities declines in response to perceived or actual adverse changes in the economy, economic outlook or financial markets; deterioration in investor sentiment; inflation, interest rate, currency, and commodity price fluctuations; adverse geopolitical, social or environmental developments; issuer- and sector-specific considerations; unexpected trading activity among retail investors; and other factors. Market conditions affect certain types of equity securities to a greater extent than other types of equity securities. If the stock market declines, the value of the  Fund’s equity securities will also likely decline, which will result in a decrease in the value of your investment in the Fund. Although prices can rebound, there is no assurance that prices of the Fund’s equity securities will return to previous levels.
(MSIF - Opportunity Portfolios) | (Global Opportunity Portfolio) | Active Management Risk [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock
•
Active Management Risk. In pursuing the Fund’s investment objective, the Adviser has considerable leeway in deciding which investments to buy, hold or sell on a day-to-day basis, and which trading strategies to use. For example, the Adviser, in its discretion, may determine to use some permitted trading strategies while not using others. The success or failure of such decisions will affect the Fund’s performance.
(MSIF - Opportunity Portfolios) | (Global Opportunity Portfolio) | Focused Investing [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock
•
Focused Investing. Although the Fund is a diversified investment company under the Investment Company Act of 1940 (the “1940 Act”), the Fund typically invests a significant portion of its portfolio in a limited number of issuers, which may be in the same industry, sector or geographic region. As a result, the Fund will be more susceptible to risks associated with, and negative events affecting those issuers, industries, sectors or geographic regions, and a decline in the value of a particular instrument may cause the Fund’s overall value to be more volatile and decline to a greater degree than if the Fund were invested more widely.
(MSIF - Opportunity Portfolios) | (Global Opportunity Portfolio) | Foreign and Emerging Market Securities [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock
•
Foreign and Emerging Market Securities. Investments in foreign markets entail special risks, such as currency, political (including geopolitical), economic and market risks and heightened risks, that may result in losses to the Fund. There also may be greater market volatility, less reliable financial information, less stringent investor protections and disclosure standards, higher transaction and custody costs and risks, 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 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 (including regional and global, military, or other conflicts), the imposition of economic sanctions against a particular country or countries, organizations, companies, entities and/or individuals, changes in international trading patterns, trade barriers (including tariffs) and other protectionist or retaliatory measures. Investments in foreign markets may also be adversely affected by governmental interventions or other 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 and decline in value in response to market developments or adverse investor perceptions, or become illiquid after purchase by the Fund, particularly during periods of market, economic, political and social 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.  Emerging market countries may be subject to increased potential for market manipulation and 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 market countries. 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 or other similar measures may be, and have been, imposed against certain countries, organizations, companies, entities and/or individuals. Economic sanctions and other similar measures could, among other things, effectively restrict or eliminate the Fund’s ability to purchase or sell securities (in the sanctioned country and other markets), negatively impact the value or liquidity of  the Fund’s investments, significantly delay or prevent the settlement of the Fund’s securities transactions, force the Fund to sell or otherwise dispose of investments at inopportune times or prices, or impair the Fund’s ability to meet its investment objective or invest in accordance with its investment strategies.
(MSIF - Opportunity Portfolios) | (Global Opportunity Portfolio) | Market and Geopolitical Risk [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock
•
Market and Geopolitical Risk. The value of your investment in the Fund is based on the values of the Fund’s investments, which change due to economic, geopolitical and other events that affect the U.S. and global markets generally, as well as those that affect or are perceived or expected to affect particular regions, countries, industries, companies, issuers, sectors, asset classes or governments. These types of events may be sudden and unexpected, and could adversely affect the value (or income generated by) and liquidity of the Fund’s investments, which may in turn impact 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 or events, epidemics and pandemics, terrorism, conflicts, social unrest, recessions, inflation, interest rate changes, supply chain disruptions and the imposition of tariffs, trade barriers and other protectionist or retaliatory measures)  adversely interrupt or otherwise affect the global economy and financial markets. It is difficult to predict when events affecting the  U.S. or global financial markets or economies may occur, the effects that such events may have and the duration of those effects (which may last for extended periods). These types of events may negatively impact broad segments of businesses and populations and have a significant and rapid negative impact on the performance or value 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. The frequency and magnitude of resulting changes in the value of the Fund’s investments cannot be predicted.
(MSIF - Opportunity Portfolios) | (Global Opportunity Portfolio) | Liquidity [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock
•
Liquidity. The Fund may make investments that are less liquid, illiquid or restricted or that may become illiquid or 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.  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 and may be unable to sell the security at all.
(MSIF - Opportunity Portfolios) | (Global Opportunity Portfolio) | China Risk [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock
•
China Risk. Investments in securities of Chinese issuers, including A-shares, involve risks associated with investments in foreign markets as well as special considerations not typically associated with investments in the  U.S. securities markets. For example, the Chinese government has historically exercised substantial control over virtually every sector of the Chinese economy through administrative regulation and/or state ownership and actions of the Chinese central and local government authorities continue to have a substantial effect on economic conditions in China. In addition, the Chinese government has taken actions that influenced the prices at which certain goods may be sold, encouraged companies to invest or concentrate in particular industries, induced mergers between companies in certain industries and induced private companies to publicly offer their securities. Investments in China involve risk of a total loss due to government action or inaction or other adverse circumstances.
 
Additionally, the Chinese economy is export-driven and highly reliant on trade. Adverse changes to the economic conditions, trading policies and taxation of imports of its primary trading partners, such as the United States, Japan and South Korea, would adversely impact the Chinese economy and the Fund’s investments. Moreover, a slowdown in other significant economies of the world, such as the United States, the European Union and certain Asian countries, may adversely affect economic growth or the value of investments in China. An economic downturn in China would adversely impact the Fund’s investments. In addition, certain securities are, or may in the future, become restricted, and/or sanctioned by the  U.S. government or other governments and the Fund may be forced to sell or unable to purchase or sell such restricted securities and incur a loss as a result.
 
Recent developments in relations between the  U.S., other trading partners and China have heightened concerns of increased tariffs and restrictions on trade between the two countries. An increase in tariffs or trade restrictions (and threats thereof) could lead to a significant reduction in international trade, which could have a negative impact on China’s export industry, Chinese issuers, the liquidity or price of the Fund’s direct or indirect investments in China and, therefore, the Fund.
 
These and other developments, including government actions, may result in significant  illiquidity risk or forced disposition for Chinese investments. The Chinese securities markets are emerging markets characterized by a relatively small number of equity issues and relatively low trading volume, resulting in decreased liquidity, greater price volatility (caused by, among other things, military, diplomatic, or trade conflicts), and potentially fewer investment opportunities for the Fund. The Fund’s investments in Chinese securities are also subject to additional risks associated with differing regulatory and audit requirements across the Chinese and  U.S. securities markets. Ongoing political tension between the People’s Republic of China and the Hong Kong Special Administrative Region may have impacts on the economy of Hong Kong, and these impacts remain uncertain.
 
Risks of Investing through Stock Connect. The Fund may invest in A-shares listed and traded through Stock Connect, or on such other stock exchanges in China which participate in Stock Connect from time to time or in the future. Trading through Stock Connect is subject to a number of restrictions that may affect the Fund’s investments and returns. Moreover, Stock Connect A-shares generally may not be sold, purchased or otherwise transferred other than through Stock Connect in accordance with applicable rules. The Stock Connect program is a relatively new program and may be subject to further interpretation and guidance. There can be no assurance as to the program’s continued existence or whether future developments regarding the program may restrict or adversely affect the Fund’s investments or returns. Because certain transactions through Stock Connect may not be subject to certain investor protection programs, the Fund may be exposed to the risks of default of the broker(s) they engage in their trading in China A Shares.
 
Variable Interest Entities. Chinese operating companies sometimes rely on variable interest entity (“VIE”) structures to raise capital from non-Chinese investors because of Chinese government limitations or prohibitions on direct foreign ownership in certain industries. In a VIE structure, a series of contractual arrangements are entered into between a holding company domiciled outside of China and a Chinese operating company or companies, which are intended to mimic direct ownership in the operating company, but in many cases these arrangements have not been tested in court and it is not clear that the contracts are enforceable or that the structures will otherwise work as intended. The offshore holding company, which is not a Chinese operating company, then issues exchange-traded shares that are sold to the public, including non-Chinese investors (such as the Fund). Shares of the offshore entity purchased by the Fund would not be equity ownership interests in the Chinese operating company and the Fund’s interest would be subject to legal, operational and other risks associated with the company’s use of the VIE structure. For example, at any time the Chinese government could determine that the contractual arrangements constituting part of the VIE structure are unenforceable or do not comply with applicable law or regulations, these laws or regulations could change or be interpreted differently in the future, and the Chinese government may with no advance notice otherwise intervene in or exert influence over VIE structures or the related Chinese operating companies. If any of these or similar risks or developments materialize, the Fund’s investment in the offshore entity may suddenly and significantly decline in value or become worthless because of, among other things, difficulty enforcing (or the inability to enforce) the contractual arrangements or materially adverse effects on the Chinese operating company’s performance. In these circumstances, the Fund could experience significant losses with no recourse available. From time to time, the Fund’s investments in U.S.-listed shell companies relying on VIE structures to consolidate China-based operations could be significant.
(MSIF - Opportunity Portfolios) | (Global Opportunity Portfolio) | India Risk [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock
•
India Risk. To the extent that the Fund invests a substantial portion of its assets in Indian issuers, the value of the Fund’s assets may be adversely affected by political, economic, social and religious factors impacting Indian businesses and the Indian economy, changes in Indian law or regulations and the status of India’s relations with other countries. Indian government actions in the future could have a significant effect on the Indian economy, which could affect private sector companies and the Fund, market conditions, and prices and yields of securities in the Fund’s portfolio. To the extent the Fund invests a significant portion of its assets in Indian businesses and the Indian economy, factors that have an adverse impact on Indian businesses and the Indian economy may have a disproportionate impact on the Fund’s performance.
(MSIF - Opportunity Portfolios) | (Global Opportunity Portfolio) | Consumer Discretionary Sector Risk [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock
•
Consumer Discretionary Sector Risk. To the extent that the Fund invests a substantial portion of its assets in the consumer discretionary sector,  the Fund will be particularly susceptible to the risks associated with companies operating in such sector(s). Companies in the consumer discretionary sector are subject to risks, including fluctuations in the performance of the overall domestic and international economy, shipment and supply chain disruptions, interest rate changes, currency exchange rates, increased competition and consumer confidence. Performance of such companies may also be adversely affected by factors such as reduced disposable household income, reduced consumer spending, and changing demographics and consumer tastes.
(MSIF - Opportunity Portfolios) | (Global Opportunity Portfolio) | Information Technology Sector Risk [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock
•
Information Technology Sector Risk. To the extent the Fund invests a substantial portion of its assets in the information technology sector, the value of Fund shares may be particularly impacted by events that adversely affect the information technology sector, such as rapid changes in technology product cycles, product obsolescence, government regulation, and competition, and may fluctuate more than that of a fund that does not invest significantly in companies in the technology sector.
(MSIF - Opportunity Portfolios) | (Global Opportunity Portfolio) | MSCI All Country World Net Index (reflects no deduction for fees, expenses or taxes)  
Prospectus: rr_ProspectusTable  
1 Year rr_AverageAnnualReturnYear01 17.49% [19]
5 Years rr_AverageAnnualReturnYear05 10.06% [19]
10 Years rr_AverageAnnualReturnYear10 9.23% [19]
Since Inception rr_AverageAnnualReturnSinceInception 6.85% [19],[20]
(MSIF - Opportunity Portfolios) | (Global Opportunity Portfolio) | Class I  
Prospectus: rr_ProspectusTable  
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum Deferred Sales Charge (as a percentage) rr_MaximumDeferredSalesChargeOverOther none
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.74% [21]
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets none
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 0.19% [22]
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 0.93%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets none
Total Annual Fund Operating Expenses After Expense Reimbursement rr_NetExpensesOverAssets 0.93%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 95
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 296
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 515
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,143
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 95
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 296
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 515
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 $ 1,143
Annual Return 2015 rr_AnnualReturn2015 18.50%
Annual Return 2016 rr_AnnualReturn2016 1.05%
Annual Return 2017 rr_AnnualReturn2017 49.44%
Annual Return 2018 rr_AnnualReturn2018 (5.66%)
Annual Return 2019 rr_AnnualReturn2019 35.44%
Annual Return 2020 rr_AnnualReturn2020 55.47%
Annual Return 2021 rr_AnnualReturn2021 0.22%
Annual Return 2022 rr_AnnualReturn2022 (41.54%)
Annual Return 2023 rr_AnnualReturn2023 49.70%
Annual Return 2024 rr_AnnualReturn2024 27.43%
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel High Quarter
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 31.66%
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Jun. 30, 2020
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel Low Quarter
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (27.33%)
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Jun. 30, 2022
1 Year rr_AverageAnnualReturnYear01 27.43% [18]
5 Years rr_AverageAnnualReturnYear05 11.69% [18]
10 Years rr_AverageAnnualReturnYear10 14.79% [18]
Since Inception rr_AverageAnnualReturnSinceInception 12.81% [18]
(MSIF - Opportunity Portfolios) | (Global Opportunity Portfolio) | Class I | Return After Taxes on Distributions  
Prospectus: rr_ProspectusTable  
1 Year rr_AverageAnnualReturnYear01 24.97% [18],[23]
5 Years rr_AverageAnnualReturnYear05 9.81% [18],[23]
10 Years rr_AverageAnnualReturnYear10 13.56% [18],[23]
Since Inception rr_AverageAnnualReturnSinceInception 11.68% [18],[23]
(MSIF - Opportunity Portfolios) | (Global Opportunity Portfolio) | Class I | Return After Taxes on Distributions and Sale of Fund Shares  
Prospectus: rr_ProspectusTable  
1 Year rr_AverageAnnualReturnYear01 18.15% [18]
5 Years rr_AverageAnnualReturnYear05 8.89% [18]
10 Years rr_AverageAnnualReturnYear10 12.15% [18]
Since Inception rr_AverageAnnualReturnSinceInception 10.71% [18]
(MSIF - Opportunity Portfolios) | (Global Opportunity Portfolio) | Class A  
Prospectus: rr_ProspectusTable  
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice 5.25%
Maximum Deferred Sales Charge (as a percentage) rr_MaximumDeferredSalesChargeOverOther none [24]
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.74% [21]
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets 0.25%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 0.23% [22]
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 1.22%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets none
Total Annual Fund Operating Expenses After Expense Reimbursement rr_NetExpensesOverAssets 1.22%
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 12 months, except for certain specific circumstances. See “Shareholder Information—How To Redeem Fund Shares” for further information about the CDSC waiver categories.
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 643
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 892
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 1,160
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,925
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 643
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 892
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 1,160
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 $ 1,925
1 Year rr_AverageAnnualReturnYear01 20.43%
5 Years rr_AverageAnnualReturnYear05 10.17%
10 Years rr_AverageAnnualReturnYear10 13.83%
Since Inception rr_AverageAnnualReturnSinceInception 15.02%
(MSIF - Opportunity Portfolios) | (Global Opportunity Portfolio) | Class L  
Prospectus: rr_ProspectusTable  
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum Deferred Sales Charge (as a percentage) rr_MaximumDeferredSalesChargeOverOther none
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.74% [21]
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets 0.75% [25]
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 0.25% [22]
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 1.74%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets 0.45% [25]
Total Annual Fund Operating Expenses After Expense Reimbursement rr_NetExpensesOverAssets 1.29%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 131
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 504
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 902
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 2,014
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 131
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 504
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 902
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 $ 2,014
1 Year rr_AverageAnnualReturnYear01 26.98% [18]
5 Years rr_AverageAnnualReturnYear05 11.29% [18]
10 Years rr_AverageAnnualReturnYear10 14.36% [18]
Since Inception rr_AverageAnnualReturnSinceInception 12.40% [18]
(MSIF - Opportunity Portfolios) | (Global Opportunity Portfolio) | Class C  
Prospectus: rr_ProspectusTable  
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum Deferred Sales Charge (as a percentage) rr_MaximumDeferredSalesChargeOverOther 1.00% [26]
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.74% [21]
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets 1.00%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 0.20% [22]
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 1.94%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets none
Total Annual Fund Operating Expenses After Expense Reimbursement rr_NetExpensesOverAssets 1.94%
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.
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 297
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 609
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 1,047
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 2,078
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 197
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 609
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 1,047
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 $ 2,078
1 Year rr_AverageAnnualReturnYear01 25.16%
5 Years rr_AverageAnnualReturnYear05 10.58%
Since Inception rr_AverageAnnualReturnSinceInception 12.97% [27]
(MSIF - Opportunity Portfolios) | (Global Opportunity Portfolio) | Class R6  
Prospectus: rr_ProspectusTable  
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum Deferred Sales Charge (as a percentage) rr_MaximumDeferredSalesChargeOverOther none
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.74% [21]
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets none
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 0.13% [22]
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 0.87%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets none
Total Annual Fund Operating Expenses After Expense Reimbursement rr_NetExpensesOverAssets 0.87%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 89
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 278
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 482
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,073
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 89
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 278
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 482
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 $ 1,073
1 Year rr_AverageAnnualReturnYear01 27.56%
5 Years rr_AverageAnnualReturnYear05 11.79%
10 Years rr_AverageAnnualReturnYear10 14.87%
Since Inception rr_AverageAnnualReturnSinceInception 15.63%
(MSIF - Opportunity Portfolios) | (International Advantage Portfolio)  
Prospectus: rr_ProspectusTable  
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock
The International Advantage Portfolio (the “Fund”) seeks long-term capital appreciation.
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 shares of the Fund and/or certain other Morgan Stanley Funds 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, amounts to $50,000 or more. More information about this combined purchase discount and other discounts is available from your authorized financial intermediary, on page 62 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 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 shares of the Fund and/or certain other Morgan Stanley Funds 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, amounts to $50,000 or more.
Expense Breakpoint, Minimum Investment Required [Amount] rr_ExpenseBreakpointMinimumInvestmentRequiredAmount $ 50,000
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 below assumes that you invest $10,000 in the Fund, your investment has a 5% return each year and 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 26%  of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 26.00%
Strategy [Heading] rr_StrategyHeading Principal Investment Strategies
Strategy Narrative [Text Block] rr_StrategyNarrativeTextBlock
Under normal market conditions, the Adviser seeks to achieve the Fund’s investment objective by investing primarily in established companies on an international basis, with capitalizations within the range of companies included in the MSCI All Country World ex USA Index.
The Adviser emphasizes a bottom-up stock selection process, seeking attractive investments on an individual company basis. In selecting securities for investment, the Adviser seeks high quality established companies that the Adviser believes are undervalued at the time of purchase. The Adviser typically favors companies it believes have sustainable competitive advantages that can be monetized through growth. The investment process integrates analysis of sustainability with respect to disruptive change, financial strength, environmental and social externalities and governance (also referred to as ESG). The Adviser typically focuses a significant portion of the Fund’s investments in a limited number of issuers, which may be in the same industry, sector or geographic region. The Adviser generally considers selling a portfolio holding when it determines that the holding no longer satisfies its investment criteria.
The Adviser views incorporating ESG-related potential risks and opportunities within the investment process as important to ensure long-term stewardship of capital. Over extended time horizons, the Adviser believes that ESG risks are more likely to materialize and externalities not borne by the company are more likely to be priced into the value of securities. Since ESG risks could potentially impact the risk and reward profile of investment opportunities, the Adviser typically engages company management in constructive discussions on a range of ESG issues the Adviser deems materially important.
The Fund may invest in equity securities. The Fund may also invest in privately placed and restricted securities.
The Fund may invest in China A-Shares (shares of publicly traded companies based in mainland China) listed and traded on the Shanghai Stock Exchange through the Shanghai-Hong Kong Stock Connect program, as well as China A-Shares listed and traded on the Shenzhen-Hong Kong Stock Connect program (collectively, “Stock Connect”).
The Fund may invest in foreign securities, which may include emerging market securities. Under normal market conditions, the Fund typically invests at least 80% of its assets in the securities of issuers located outside of the United States. For purposes of maintaining exposure of at least 80% of the Fund’s assets to equity securities of issuers located or operating outside the United States,
the Fund may also invest in American Depositary Receipts (“ADRs”), Global Depositary Receipts (“GDRs”) and other types of depositary receipts with respect to issuers located or operating outside the United States.
Risk [Heading] rr_RiskHeading Principal Risks
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 ten year periods and since inception compare with those of a broad measure of   market performance. 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 1-800-869-6397.
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 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 ten year periods and since inception compare with those of a broad measure of   market performance.
Performance Availability Phone [Text] rr_PerformanceAvailabilityPhone 1-800-869-6397
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 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 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
19.40%
Low Quarter
06/30/22
-20.71%
Performance Table Heading rr_PerformanceTableHeading Average Annual Total Returns(for the calendar periods ended  December 31, 2024)
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.
(MSIF - Opportunity Portfolios) | (International Advantage Portfolio) | Risk Not Insured Depository Institution [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock 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.
(MSIF - Opportunity Portfolios) | (International Advantage Portfolio) | Risk Lose Money [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock There is no assurance that the Fund will achieve its investment objective, and you can lose money investing in this Fund.
(MSIF - Opportunity Portfolios) | (International Advantage Portfolio) | Equity Securities [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock
•
Equity Securities. In general, prices of equity securities are more volatile than those of fixed-income securities. U.S. and foreign stock markets, and equity securities of individual issuers, have experienced periods of substantial price volatility in the past and it is possible that they will do so again in the future. The prices of equity securities fluctuate, sometimes rapidly or widely, 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, political and public health conditions.  During periods when equity securities experience heightened volatility, such as during periods of market, economic or financial uncertainty or distress, the Fund’s investments in equity securities are subject to heightened risks.
 
The value of equity securities declines in response to perceived or actual adverse changes in the economy, economic outlook or financial markets; deterioration in investor sentiment; inflation, interest rate, currency, and commodity price fluctuations; adverse geopolitical, social or environmental developments; issuer- and sector-specific considerations; unexpected trading activity among retail investors; and other factors. Market conditions affect certain types of equity securities to a greater extent than other types of equity securities. If the stock market declines, the value of the  Fund’s equity securities will also likely decline, which will result in a decrease in the value of your investment in the Fund. Although prices can rebound, there is no assurance that prices of the Fund’s equity securities will return to previous levels.
(MSIF - Opportunity Portfolios) | (International Advantage Portfolio) | Active Management Risk [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock
•
Active Management Risk. In pursuing the Fund’s investment objective, the Adviser has considerable leeway in deciding which investments to buy, hold or sell on a day-to-day basis, and which trading strategies to use. For example, the Adviser, in its discretion, may determine to use some permitted trading strategies while not using others. The success or failure of such decisions will affect the Fund’s performance.
(MSIF - Opportunity Portfolios) | (International Advantage Portfolio) | Focused Investing [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock
•
Focused Investing. Although the Fund is a diversified investment company under the Investment Company Act of 1940 (the “1940 Act”), the Fund typically invests a significant portion of its portfolio in a limited number of issuers, which may be in the same industry, sector or geographic region. As a result, the Fund will be more susceptible to risks associated with, and negative events affecting those issuers, industries, sectors or geographic regions, and a decline in the value of a particular instrument may cause the Fund’s overall value to be more volatile and decline to a greater degree than if the Fund were invested more widely.
(MSIF - Opportunity Portfolios) | (International Advantage Portfolio) | Foreign and Emerging Market Securities [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock
•
Foreign and Emerging Market Securities. Investments in foreign markets entail special risks, such as currency, political (including geopolitical), economic and market risks and heightened risks, that may result in losses to the Fund. There also may be greater market volatility, less reliable financial information, less stringent investor protections and disclosure standards, higher transaction and custody costs and risks, 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 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 (including regional and global, military, or other conflicts), the imposition of economic sanctions against a particular country or countries, organizations, companies, entities and/or individuals, changes in international trading patterns, trade barriers (including tariffs) and other protectionist or retaliatory measures. Investments in foreign markets may also be adversely affected by governmental interventions or other 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 and decline in value in response to market developments or adverse investor perceptions, or become illiquid after purchase by the Fund, particularly during periods of market, economic, political and social 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.  Emerging market countries may be subject to increased potential for market manipulation and 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 market countries. 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 or other similar measures may be, and have been, imposed against certain countries, organizations, companies, entities and/or individuals. Economic sanctions and other similar measures could, among other things, effectively restrict or eliminate the Fund’s ability to purchase or sell securities (in the sanctioned country and other markets), negatively impact the value or liquidity of  the Fund’s investments, significantly delay or prevent the settlement of the Fund’s securities transactions, force the Fund to sell or otherwise dispose of investments at inopportune times or prices, or impair the Fund’s ability to meet its investment objective or invest in accordance with its investment strategies.
(MSIF - Opportunity Portfolios) | (International Advantage Portfolio) | Market and Geopolitical Risk [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock
•
Market and Geopolitical Risk. The value of your investment in the Fund is based on the values of the Fund’s investments, which change due to economic, geopolitical and other events that affect the U.S. and global markets generally, as well as those that affect or are perceived or expected to affect particular regions, countries, industries, companies, issuers, sectors, asset classes or governments. These types of events may be sudden and unexpected, and could adversely affect the value (or income generated by) and liquidity of the Fund’s investments, which may in turn impact 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 or events, epidemics and pandemics, terrorism, conflicts, social unrest, recessions, inflation, interest rate changes, supply chain disruptions and the imposition of tariffs, trade barriers and other protectionist or retaliatory measures)  adversely interrupt or otherwise affect the global economy and financial markets. It is difficult to predict when events affecting the  U.S. or global financial markets or economies may occur, the effects that such events may have and the duration of those effects (which may last for extended periods). These types of events may negatively impact broad segments of businesses and populations and have a significant and rapid negative impact on the performance or value 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. The frequency and magnitude of resulting changes in the value of the Fund’s investments cannot be predicted.
(MSIF - Opportunity Portfolios) | (International Advantage Portfolio) | Liquidity [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock
•
Liquidity. The Fund may make investments that are less liquid, illiquid or restricted or that may become illiquid or 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.  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 and may be unable to sell the security at all.
(MSIF - Opportunity Portfolios) | (International Advantage Portfolio) | India Risk [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock
•
India Risk. To the extent that the Fund invests a substantial portion of its assets in Indian issuers, the value of the Fund’s assets may be adversely affected by political, economic, social and religious factors impacting Indian businesses and the Indian economy, changes in Indian law or regulations and the status of India’s relations with other countries. Indian government actions in the future could have a significant effect on the Indian economy, which could affect private sector companies and the Fund, market conditions, and prices and yields of securities in the Fund’s portfolio. To the extent the Fund invests a significant portion of its assets in Indian businesses and the Indian economy, factors that have an adverse impact on Indian businesses and the Indian economy may have a disproportionate impact on the Fund’s performance.
(MSIF - Opportunity Portfolios) | (International Advantage Portfolio) | Consumer Discretionary Sector Risk [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock
•
Consumer Discretionary Sector Risk. To the extent that the Fund invests a substantial portion of its assets in the consumer discretionary sector,  the Fund will be particularly susceptible to the risks associated with companies operating in such sector(s). Companies in the consumer discretionary sector are subject to risks, including fluctuations in the performance of the overall domestic and international economy, shipment and supply chain disruptions, interest rate changes, currency exchange rates, increased competition and consumer confidence. Performance of such companies may also be adversely affected by factors such as reduced disposable household income, reduced consumer spending, and changing demographics and consumer tastes.
(MSIF - Opportunity Portfolios) | (International Advantage Portfolio) | MSCI All Country World ex USA Net Index (reflects no deduction for fees, expenses or taxes)  
Prospectus: rr_ProspectusTable  
1 Year rr_AverageAnnualReturnYear01 5.53% [28]
5 Years rr_AverageAnnualReturnYear05 4.10% [28]
10 Years rr_AverageAnnualReturnYear10 4.80% [28]
Since Inception rr_AverageAnnualReturnSinceInception 4.31% [28],[29]
(MSIF - Opportunity Portfolios) | (International Advantage Portfolio) | Class I  
Prospectus: rr_ProspectusTable  
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum Deferred Sales Charge (as a percentage) rr_MaximumDeferredSalesChargeOverOther none
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.77% [30]
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets none
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 0.23% [31]
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 1.00% [32]
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets none [32]
Total Annual Fund Operating Expenses After Expense Reimbursement rr_NetExpensesOverAssets 1.00% [32]
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 102
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 318
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 552
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,225
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 102
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 318
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 552
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 $ 1,225
Annual Return 2015 rr_AnnualReturn2015 10.23%
Annual Return 2016 rr_AnnualReturn2016 2.47%
Annual Return 2017 rr_AnnualReturn2017 44.75%
Annual Return 2018 rr_AnnualReturn2018 (5.19%)
Annual Return 2019 rr_AnnualReturn2019 30.09%
Annual Return 2020 rr_AnnualReturn2020 32.33%
Annual Return 2021 rr_AnnualReturn2021 13.16%
Annual Return 2022 rr_AnnualReturn2022 (34.46%)
Annual Return 2023 rr_AnnualReturn2023 18.38%
Annual Return 2024 rr_AnnualReturn2024 6.95%
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel High Quarter
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 19.40%
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Jun. 30, 2020
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel Low Quarter
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (20.71%)
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Jun. 30, 2022
1 Year rr_AverageAnnualReturnYear01 6.95%
5 Years rr_AverageAnnualReturnYear05 4.44%
10 Years rr_AverageAnnualReturnYear10 9.62%
Since Inception rr_AverageAnnualReturnSinceInception 9.27%
(MSIF - Opportunity Portfolios) | (International Advantage Portfolio) | Class I | Return After Taxes on Distributions  
Prospectus: rr_ProspectusTable  
1 Year rr_AverageAnnualReturnYear01 7.13% [33]
5 Years rr_AverageAnnualReturnYear05 4.24% [33]
10 Years rr_AverageAnnualReturnYear10 8.97% [33]
Since Inception rr_AverageAnnualReturnSinceInception 8.62% [33]
(MSIF - Opportunity Portfolios) | (International Advantage Portfolio) | Class I | Return After Taxes on Distributions and Sale of Fund Shares  
Prospectus: rr_ProspectusTable  
1 Year rr_AverageAnnualReturnYear01 4.36%
5 Years rr_AverageAnnualReturnYear05 3.50%
10 Years rr_AverageAnnualReturnYear10 7.70%
Since Inception rr_AverageAnnualReturnSinceInception 7.56%
(MSIF - Opportunity Portfolios) | (International Advantage Portfolio) | Class A  
Prospectus: rr_ProspectusTable  
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice 5.25%
Maximum Deferred Sales Charge (as a percentage) rr_MaximumDeferredSalesChargeOverOther none [34]
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.77% [30]
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets 0.25%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 0.26% [31]
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 1.28% [32]
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets none [32]
Total Annual Fund Operating Expenses After Expense Reimbursement rr_NetExpensesOverAssets 1.28% [32]
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 12 months, except for certain specific circumstances. See “Shareholder Information—How To Redeem Fund Shares” for further information about the CDSC waiver categories.
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 649
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 910
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 1,190
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,989
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 649
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 910
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 1,190
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 $ 1,989
1 Year rr_AverageAnnualReturnYear01 1.04%
5 Years rr_AverageAnnualReturnYear05 3.02%
10 Years rr_AverageAnnualReturnYear10 8.69%
Since Inception rr_AverageAnnualReturnSinceInception 8.53%
(MSIF - Opportunity Portfolios) | (International Advantage Portfolio) | Class L  
Prospectus: rr_ProspectusTable  
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum Deferred Sales Charge (as a percentage) rr_MaximumDeferredSalesChargeOverOther none
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.77% [30]
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets 0.75%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 0.67% [31]
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 2.19% [32]
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets 0.34% [32]
Total Annual Fund Operating Expenses After Expense Reimbursement rr_NetExpensesOverAssets 1.85% [32]
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 188
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 653
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 1,144
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 2,497
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 188
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 653
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 1,144
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 $ 2,497
1 Year rr_AverageAnnualReturnYear01 5.99%
5 Years rr_AverageAnnualReturnYear05 3.53%
10 Years rr_AverageAnnualReturnYear10 8.69%
Since Inception rr_AverageAnnualReturnSinceInception 8.37%
(MSIF - Opportunity Portfolios) | (International Advantage Portfolio) | Class C  
Prospectus: rr_ProspectusTable  
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum Deferred Sales Charge (as a percentage) rr_MaximumDeferredSalesChargeOverOther 1.00% [35]
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.77% [30]
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets 1.00%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 0.23% [31]
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 2.00% [32]
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets none [32]
Total Annual Fund Operating Expenses After Expense Reimbursement rr_NetExpensesOverAssets 2.00% [32]
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.
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 303
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 627
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 1,078
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 2,142
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 203
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 627
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 1,078
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 $ 2,142
1 Year rr_AverageAnnualReturnYear01 4.86%
5 Years rr_AverageAnnualReturnYear05 3.40%
Since Inception rr_AverageAnnualReturnSinceInception 7.66% [36]
(MSIF - Opportunity Portfolios) | (International Advantage Portfolio) | Class R6  
Prospectus: rr_ProspectusTable  
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum Deferred Sales Charge (as a percentage) rr_MaximumDeferredSalesChargeOverOther none
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.77% [30]
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets none
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 0.12% [31]
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 0.89% [32]
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets none [32]
Total Annual Fund Operating Expenses After Expense Reimbursement rr_NetExpensesOverAssets 0.89% [32]
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 91
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 284
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 493
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,096
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 91
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 284
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 493
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 $ 1,096
1 Year rr_AverageAnnualReturnYear01 7.04%
5 Years rr_AverageAnnualReturnYear05 4.55%
Since Inception rr_AverageAnnualReturnSinceInception 5.02%
(MSIF - Opportunity Portfolios) | (International Opportunity Portfolio)  
Prospectus: rr_ProspectusTable  
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock
The International Opportunity Portfolio (the “Fund”) seeks long-term capital appreciation.
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 shares of the Fund and/or certain other Morgan Stanley Funds 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, amounts to $50,000 or more. More information about this combined purchase discount and other discounts is available from your authorized financial intermediary, on page 62 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 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 shares of the Fund and/or certain other Morgan Stanley Funds 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, amounts to $50,000 or more.
Expense Breakpoint, Minimum Investment Required [Amount] rr_ExpenseBreakpointMinimumInvestmentRequiredAmount $ 50,000
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 28%  of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 28.00%
Strategy [Heading] rr_StrategyHeading Principal Investment Strategies
Strategy Narrative [Text Block] rr_StrategyNarrativeTextBlock
Under normal market conditions, the Adviser seeks to achieve the Fund’s investment objective by investing primarily in established and emerging companies on an international basis, with capitalizations within the range of companies included in the MSCI All Country World ex USA Index.
The Adviser emphasizes a bottom-up stock selection process, seeking attractive investments on an individual company basis. In selecting securities for investment, the Adviser seeks high quality established and emerging companies that the Adviser believes are undervalued at the time of purchase. Fundamental research drives the investment process. The Adviser typically favors companies it believes have sustainable competitive advantages that can be monetized through growth. The investment process integrates analysis of sustainability with respect to disruptive change, financial strength, environmental and social externalities and governance (also referred to as ESG). The Adviser typically focuses a significant portion of the Fund’s investments in a limited number of issuers, which may be in the same industry, sector or geographic region. The Adviser  generally considers selling a portfolio holding when it determines that the holding no longer satisfies its investment criteria.
The Adviser views incorporating ESG-related potential risks and opportunities within the investment process as important to ensure long-term stewardship of capital. Over extended time horizons, the Adviser believes that ESG risks are more likely to materialize and externalities not borne by the company are more likely to be priced into the value of securities. Since ESG risks could potentially impact the risk and reward profile of investment opportunities, the Adviser typically engages company management in constructive discussions on a range of ESG issues the Adviser deems materially important.
The Fund may invest in China A-Shares (shares of publicly traded companies based in mainland China) listed and traded on the Shanghai Stock Exchange through the Shanghai-Hong Kong Stock Connect program, as well as China A-Shares listed and traded on the Shenzhen-Hong Kong Stock Connect program (collectively, “Stock Connect”).
The Fund may also invest in American Depositary Receipts (“ADRs”), Global Depositary Receipts (“GDRs”) and other types of depositary receipts with respect to issuers located or operating outside of the United States. The Fund may invest in equity securities. The Fund may also invest in privately placed and restricted securities.
The Fund invests primarily in securities of companies located in Europe, Japan, Asia, the Pacific Basin, Latin America, the Middle East and Africa. The Fund may also invest in securities of companies located in the United States to a limited extent.
Risk [Heading] rr_RiskHeading Principal Risks
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 ten year periods and since inception compare with those of a broad measure of   market performance. 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 1-800-869-6397.
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 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 ten year periods and since inception compare with those of a broad measure of   market performance.
Performance Availability Phone [Text] rr_PerformanceAvailabilityPhone 1-800-869-6397
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 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 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 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
34.02%
Low Quarter
03/31/22
-26.33%
Performance Table Heading rr_PerformanceTableHeading Average Annual Total Returns(for the calendar periods ended  December 31, 2024)
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 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.
(MSIF - Opportunity Portfolios) | (International Opportunity Portfolio) | Risk Not Insured Depository Institution [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock 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.
(MSIF - Opportunity Portfolios) | (International Opportunity Portfolio) | Risk Lose Money [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock There is no assurance that the Fund will achieve its investment objective, and you can lose money investing in this Fund.
(MSIF - Opportunity Portfolios) | (International Opportunity Portfolio) | Equity Securities [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock
•
Equity Securities. In general, prices of equity securities are more volatile than those of fixed-income securities. U.S. and foreign stock markets, and equity securities of individual issuers, have experienced periods of substantial price volatility in the past and it is possible that they will do so again in the future. The prices of equity securities fluctuate, sometimes rapidly or widely, 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, political and public health conditions.  During periods when equity securities experience heightened volatility, such as during periods of market, economic or financial uncertainty or distress, the Fund’s investments in equity securities are subject to heightened risks.
 
The value of equity securities declines in response to perceived or actual adverse changes in the economy, economic outlook or financial markets; deterioration in investor sentiment; inflation, interest rate, currency, and commodity price fluctuations; adverse geopolitical, social or environmental developments; issuer- and sector-specific considerations; unexpected trading activity among retail investors; and other factors. Market conditions affect certain types of equity securities to a greater extent than other types of equity securities. If the stock market declines, the value of the  Fund’s equity securities will also likely decline, which will result in a decrease in the value of your investment in the Fund. Although prices can rebound, there is no assurance that prices of the Fund’s equity securities will return to previous levels.
(MSIF - Opportunity Portfolios) | (International Opportunity Portfolio) | Active Management Risk [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock
•
Active Management Risk. In pursuing the Fund’s investment objective, the Adviser has considerable leeway in deciding which investments to buy, hold or sell on a day-to-day basis, and which trading strategies to use. For example, the Adviser, in its discretion, may determine to use some permitted trading strategies while not using others. The success or failure of such decisions will affect the Fund’s performance.
(MSIF - Opportunity Portfolios) | (International Opportunity Portfolio) | Focused Investing [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock
•
Focused Investing. Although the Fund is a diversified investment company under the Investment Company Act of 1940 (the “1940 Act”), the Fund typically invests a significant portion of its portfolio in a limited number of issuers, which may be in the same industry, sector or geographic region. As a result, the Fund will be more susceptible to risks associated with, and negative events affecting those issuers, industries, sectors or geographic regions, and a decline in the value of a particular instrument may cause the Fund’s overall value to be more volatile and decline to a greater degree than if the Fund were invested more widely.
(MSIF - Opportunity Portfolios) | (International Opportunity Portfolio) | Foreign and Emerging Market Securities [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock
•
Foreign and Emerging Market Securities. Investments in foreign markets entail special risks, such as currency, political (including geopolitical), economic and market risks and heightened risks, that may result in losses to the Fund. There also may be greater market volatility, less reliable financial information, less stringent investor protections and disclosure standards, higher transaction and custody costs and risks, 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 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 (including regional and global, military, or other conflicts), the imposition of economic sanctions against a particular country or countries, organizations, companies, entities and/or individuals, changes in international trading patterns, trade barriers (including tariffs) and other protectionist or retaliatory measures. Investments in foreign markets may also be adversely affected by governmental interventions or other 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 and decline in value in response to market developments or adverse investor perceptions, or become illiquid after purchase by the Fund, particularly during periods of market, economic, political and social 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.  Emerging market countries may be subject to increased potential for market manipulation and 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 market countries. 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 or other similar measures may be, and have been, imposed against certain countries, organizations, companies, entities and/or individuals. Economic sanctions and other similar measures could, among other things, effectively restrict or eliminate the Fund’s ability to purchase or sell securities (in the sanctioned country and other markets), negatively impact the value or liquidity of  the Fund’s investments, significantly delay or prevent the settlement of the Fund’s securities transactions, force the Fund to sell or otherwise dispose of investments at inopportune times or prices, or impair the Fund’s ability to meet its investment objective or invest in accordance with its investment strategies.
(MSIF - Opportunity Portfolios) | (International Opportunity Portfolio) | Market and Geopolitical Risk [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock
•
Market and Geopolitical Risk. The value of your investment in the Fund is based on the values of the Fund’s investments, which change due to economic, geopolitical and other events that affect the U.S. and global markets generally, as well as those that affect or are perceived or expected to affect particular regions, countries, industries, companies, issuers, sectors, asset classes or governments. These types of events may be sudden and unexpected, and could adversely affect the value (or income generated by) and liquidity of the Fund’s investments, which may in turn impact 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 or events, epidemics and pandemics, terrorism, conflicts, social unrest, recessions, inflation, interest rate changes, supply chain disruptions and the imposition of tariffs, trade barriers and other protectionist or retaliatory measures)  adversely interrupt or otherwise affect the global economy and financial markets. It is difficult to predict when events affecting the  U.S. or global financial markets or economies may occur, the effects that such events may have and the duration of those effects (which may last for extended periods). These types of events may negatively impact broad segments of businesses and populations and have a significant and rapid negative impact on the performance or value 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. The frequency and magnitude of resulting changes in the value of the Fund’s investments cannot be predicted.
(MSIF - Opportunity Portfolios) | (International Opportunity Portfolio) | Liquidity [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock
•
Liquidity. The Fund may make investments that are less liquid, illiquid or restricted or that may become illiquid or 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.  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 and may be unable to sell the security at all.
(MSIF - Opportunity Portfolios) | (International Opportunity Portfolio) | China Risk [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock
•
China Risk. Investments in securities of Chinese issuers, including A-shares, involve risks associated with investments in foreign markets as well as special considerations not typically associated with investments in the  U.S. securities markets. For example, the Chinese government has historically exercised substantial control over virtually every sector of the Chinese economy through administrative regulation and/or state ownership and actions of the Chinese central and local government authorities continue to have a substantial effect on economic conditions in China. In addition, the Chinese government has taken actions that influenced the prices at which certain goods may be sold, encouraged companies to invest or concentrate in particular industries, induced
mergers between companies in certain industries and induced private companies to publicly offer their securities. Investments in China involve risk of a total loss due to government action or inaction or other adverse circumstances.
 
Additionally, the Chinese economy is export-driven and highly reliant on trade. Adverse changes to the economic conditions, trading policies and taxation of imports of its primary trading partners, such as the United States, Japan and South Korea, would adversely impact the Chinese economy and the Fund’s investments. Moreover, a slowdown in other significant economies of the world, such as the United States, the European Union and certain Asian countries, may adversely affect economic growth or the value of investments in China. An economic downturn in China would adversely impact the Fund’s investments. In addition, certain securities are, or may in the future, become restricted, and/or sanctioned by the  U.S. government or other governments and the Fund may be forced to sell or unable to purchase or sell such restricted securities and incur a loss as a result.
 
Recent developments in relations between the  U.S., other trading partners and China have heightened concerns of increased tariffs and restrictions on trade between the two countries. An increase in tariffs or trade restrictions (and threats thereof) could lead to a significant reduction in international trade, which could have a negative impact on China’s export industry, Chinese issuers, the liquidity or price of the Fund’s direct or indirect investments in China and, therefore, the Fund.
 
These and other developments, including government actions, may result in significant  illiquidity risk or forced disposition for Chinese investments. The Chinese securities markets are emerging markets characterized by a relatively small number of equity issues and relatively low trading volume, resulting in decreased liquidity, greater price volatility (caused by, among other things, military, diplomatic, or trade conflicts), and potentially fewer investment opportunities for the Fund. The Fund’s investments in Chinese securities are also subject to additional risks associated with differing regulatory and audit requirements across the Chinese and  U.S. securities markets. Ongoing political tension between the People’s Republic of China and the Hong Kong Special Administrative Region may have impacts on the economy of Hong Kong, and these impacts remain uncertain.
 
Risks of Investing through Stock Connect. The Fund may invest in A-shares listed and traded through Stock Connect, or on such other stock exchanges in China which participate in Stock Connect from time to time or in the future. Trading through Stock Connect is subject to a number of restrictions that may affect the Fund’s investments and returns. Moreover, Stock Connect A-shares generally may not be sold, purchased or otherwise transferred other than through Stock Connect in accordance with applicable rules. The Stock Connect program is a relatively new program and may be subject to further interpretation and guidance. There can be no assurance as to the program’s continued existence or whether future developments regarding the program may restrict or adversely affect the Fund’s investments or returns. Because certain transactions through Stock Connect may not be subject to certain investor protection programs, the Fund may be exposed to the risks of default of the broker(s) they engage in their trading in China A Shares.
 
Variable Interest Entities. Chinese operating companies sometimes rely on variable interest entity (“VIE”) structures to raise capital from non-Chinese investors because of Chinese government limitations or prohibitions on direct foreign ownership in certain industries. In a VIE structure, a series of contractual arrangements are entered into between a holding company domiciled outside of China and a Chinese operating company or companies, which are intended to mimic direct ownership in the operating company, but in many cases these arrangements have not been tested in court and it is not clear that the contracts are enforceable or that the structures will otherwise work as intended. The offshore holding company, which is not a Chinese operating company, then issues exchange-traded shares that are sold to the public, including non-Chinese investors (such as the Fund). Shares of the offshore entity purchased by the Fund would not be equity ownership interests in the Chinese operating company and the Fund’s interest would be subject to legal, operational and other risks associated with the company’s use of the VIE structure. For example, at any time the Chinese government could determine that the contractual arrangements constituting part of the VIE structure are unenforceable or do not comply with applicable law or regulations, these laws or regulations could change or be interpreted differently in the future, and the Chinese government may with no advance notice otherwise intervene in or exert influence over VIE structures or the related Chinese operating companies. If any of these or similar risks or developments materialize, the Fund’s investment in the offshore entity may suddenly and significantly decline in value or become worthless because of, among other things, difficulty enforcing (or the inability to enforce) the contractual arrangements or materially adverse effects on the Chinese operating company’s performance. In these circumstances, the Fund could experience significant losses with no recourse available. From time to time, the Fund’s investments in U.S.-listed shell companies relying on VIE structures to consolidate China-based operations could be significant.
(MSIF - Opportunity Portfolios) | (International Opportunity Portfolio) | India Risk [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock
•
India Risk. To the extent that the Fund invests a substantial portion of its assets in Indian issuers, the value of the Fund’s assets may be adversely affected by political, economic, social and religious factors impacting Indian businesses and the Indian economy, changes in Indian law or regulations and the status of India’s relations with other countries. Indian government actions in the future could have a significant effect on the Indian economy, which could affect private sector companies and the Fund, market conditions, and prices and yields of securities in the Fund’s portfolio. To the extent the Fund invests a significant portion of its assets in Indian businesses and the Indian economy, factors that have an adverse impact on Indian businesses and the Indian economy may have a disproportionate impact on the Fund’s performance.
(MSIF - Opportunity Portfolios) | (International Opportunity Portfolio) | Consumer Discretionary Sector Risk [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock
•
Consumer Discretionary Sector Risk. To the extent that the Fund invests a substantial portion of its assets in the consumer discretionary sector,  the Fund will be particularly susceptible to the risks associated with companies operating in such sector(s). Companies in the consumer discretionary sector are subject to risks, including fluctuations in the performance of the overall domestic and international economy, shipment and supply chain disruptions, interest rate changes, currency exchange rates, increased competition and consumer confidence. Performance of such companies may also be adversely affected by factors such as reduced disposable household income, reduced consumer spending, and changing demographics and consumer tastes.
(MSIF - Opportunity Portfolios) | (International Opportunity Portfolio) | Financials Sector Risk [Member]  
Prospectus: rr_ProspectusTable  
Risk [Text Block] rr_RiskTextBlock
•
Financials Sector Risk. To the extent the Fund invests a substantial portion of its assets in the financials sector, factors that have an adverse impact on this sector may have a disproportionate impact on the Fund’s performance. The financials sector can be affected by global and local economic conditions, such as the levels and liquidity of the global and local financial and asset markets, the absolute and relative level and volatility of interest rates and equity prices, investor sentiment, inflation, and the availability and cost of credit. Adverse developments in these conditions can have a greater adverse effect on the financials sector of an emerging market economy than on other industries of its economy. The enactment of new legislation or regulations, as well as changes in interpretation and enforcement of current laws, may affect the manner of operations and profitability of the financials sector.
(MSIF - Opportunity Portfolios) | (International Opportunity Portfolio) | MSCI All Country World ex USA Net Index (reflects no deduction for fees, expenses or taxes)  
Prospectus: rr_ProspectusTable  
1 Year rr_AverageAnnualReturnYear01 5.53% [37]
5 Years rr_AverageAnnualReturnYear05 4.10% [37]
10 Years rr_AverageAnnualReturnYear10 4.80% [37]
Since Inception rr_AverageAnnualReturnSinceInception 4.65% [37],[38]
(MSIF - Opportunity Portfolios) | (International Opportunity Portfolio) | Class I  
Prospectus: rr_ProspectusTable  
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum Deferred Sales Charge (as a percentage) rr_MaximumDeferredSalesChargeOverOther none
Redemption Fee (as a percentage of Amount Redeemed) rr_RedemptionFeeOverRedemption 2.00%
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.80% [39]
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets none
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 0.26% [40]
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 1.06% [41]
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets 0.06% [41]
Total Annual Fund Operating Expenses After Expense Reimbursement rr_NetExpensesOverAssets 1.00% [41]
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 102
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 331
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 579
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,289
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 102
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 331
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 579
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 $ 1,289
Annual Return 2015 rr_AnnualReturn2015 11.40%
Annual Return 2016 rr_AnnualReturn2016 (0.65%)
Annual Return 2017 rr_AnnualReturn2017 53.38%
Annual Return 2018 rr_AnnualReturn2018 (12.04%)
Annual Return 2019 rr_AnnualReturn2019 35.20%
Annual Return 2020 rr_AnnualReturn2020 55.49%
Annual Return 2021 rr_AnnualReturn2021 (5.24%)
Annual Return 2022 rr_AnnualReturn2022 (43.76%)
Annual Return 2023 rr_AnnualReturn2023 21.11%
Annual Return 2024 rr_AnnualReturn2024 19.32%
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel High Quarter
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 34.02%
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Jun. 30, 2020
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel Low Quarter
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (26.33%)
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Mar. 31, 2022
1 Year rr_AverageAnnualReturnYear01 19.32%
5 Years rr_AverageAnnualReturnYear05 3.67%
10 Years rr_AverageAnnualReturnYear10 9.23%
Since Inception rr_AverageAnnualReturnSinceInception 9.38%
(MSIF - Opportunity Portfolios) | (International Opportunity Portfolio) | Class I | Return After Taxes on Distributions  
Prospectus: rr_ProspectusTable  
1 Year rr_AverageAnnualReturnYear01 19.49% [42]
5 Years rr_AverageAnnualReturnYear05 3.20% [42]
10 Years rr_AverageAnnualReturnYear10 8.86% [42]
Since Inception rr_AverageAnnualReturnSinceInception 8.97% [42]
(MSIF - Opportunity Portfolios) | (International Opportunity Portfolio) | Class I | Return After Taxes on Distributions and Sale of Fund Shares  
Prospectus: rr_ProspectusTable  
1 Year rr_AverageAnnualReturnYear01 11.69%
5 Years rr_AverageAnnualReturnYear05 2.84%
10 Years rr_AverageAnnualReturnYear10 7.55%
Since Inception rr_AverageAnnualReturnSinceInception 7.85%
(MSIF - Opportunity Portfolios) | (International Opportunity Portfolio) | Class A  
Prospectus: rr_ProspectusTable  
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice 5.25%
Maximum Deferred Sales Charge (as a percentage) rr_MaximumDeferredSalesChargeOverOther none [43]
Redemption Fee (as a percentage of Amount Redeemed) rr_RedemptionFeeOverRedemption 2.00%
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.80% [39]
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets 0.25%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 0.29% [40]
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 1.34% [41]
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets none [41]
Total Annual Fund Operating Expenses After Expense Reimbursement rr_NetExpensesOverAssets 1.34% [41]
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 12 months, except for certain specific circumstances. See “Shareholder Information—How To Redeem Fund Shares” for further information about the CDSC waiver categories.
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 654
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 927
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 1,221
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 2,053
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 654
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 927
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 1,221
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 $ 2,053
1 Year rr_AverageAnnualReturnYear01 12.68%
5 Years rr_AverageAnnualReturnYear05 2.24%
10 Years rr_AverageAnnualReturnYear10 8.29%
Since Inception rr_AverageAnnualReturnSinceInception 8.64%
(MSIF - Opportunity Portfolios) | (International Opportunity Portfolio) | Class L  
Prospectus: rr_ProspectusTable  
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum Deferred Sales Charge (as a percentage) rr_MaximumDeferredSalesChargeOverOther none
Redemption Fee (as a percentage of Amount Redeemed) rr_RedemptionFeeOverRedemption 2.00%
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.80% [39]
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets 0.75%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 1.47% [40]
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 3.02% [41]
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets 1.17% [41]
Total Annual Fund Operating Expenses After Expense Reimbursement rr_NetExpensesOverAssets 1.85% [41]
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 188
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 823
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 1,484
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 3,254
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 188
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 823
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 1,484
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 $ 3,254
1 Year rr_AverageAnnualReturnYear01 18.30%
5 Years rr_AverageAnnualReturnYear05 2.77%
10 Years rr_AverageAnnualReturnYear10 8.29%
Since Inception rr_AverageAnnualReturnSinceInception 8.46%
(MSIF - Opportunity Portfolios) | (International Opportunity Portfolio) | Class C  
Prospectus: rr_ProspectusTable  
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum Deferred Sales Charge (as a percentage) rr_MaximumDeferredSalesChargeOverOther 1.00% [44]
Redemption Fee (as a percentage of Amount Redeemed) rr_RedemptionFeeOverRedemption 2.00%
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.80% [39]
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets 1.00%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 0.27% [40]
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 2.07% [41]
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets none [41]
Total Annual Fund Operating Expenses After Expense Reimbursement rr_NetExpensesOverAssets 2.07% [41]
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.
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 310
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 649
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 1,114
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 2,213
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 210
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 649
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 1,114
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 $ 2,213
1 Year rr_AverageAnnualReturnYear01 17.06%
5 Years rr_AverageAnnualReturnYear05 2.60%
Since Inception rr_AverageAnnualReturnSinceInception 7.22% [45]
(MSIF - Opportunity Portfolios) | (International Opportunity Portfolio) | Class R6  
Prospectus: rr_ProspectusTable  
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum Deferred Sales Charge (as a percentage) rr_MaximumDeferredSalesChargeOverOther none
Redemption Fee (as a percentage of Amount Redeemed) rr_RedemptionFeeOverRedemption 2.00%
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.80% [39]
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets none
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 0.31% [40]
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 1.11% [41]
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets 0.17% [41]
Total Annual Fund Operating Expenses After Expense Reimbursement rr_NetExpensesOverAssets 0.94% [41]
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 96
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 336
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 595
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,336
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 96
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 336
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 595
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 $ 1,336
1 Year rr_AverageAnnualReturnYear01 19.42%
5 Years rr_AverageAnnualReturnYear05 3.75%
10 Years rr_AverageAnnualReturnYear10 9.28%
Since Inception rr_AverageAnnualReturnSinceInception 9.48%
[1]
3 The MSCI All Country Asia ex Japan Net Index is a free float-adjusted market capitalization weighted index that is designed to measure the equity market performance of Asia, excluding Japan.    The performance of the index is listed in U.S. dollars and assumes reinvestment of net dividends. Net total return indices reinvest dividends after the deduction of withholding taxes, using (for international indices) a tax rate applicable to non-resident institutional investors who do not benefit from double taxation treaties. It is not possible to invest directly in an index.
[2]
4 Since Inception reflects the inception date of the Fund.
[3]
1 “Advisory Fee” includes the management fee of a wholly-owned subsidiary of the Fund organized as a company under the laws of the Cayman Islands (the “Subsidiary”). The Fund’s “Adviser” and “Administrator,” Morgan Stanley Investment Management Inc., has agreed to waive or credit a portion of the advisory fee in an amount equal to the management fee paid to the Adviser by the Subsidiary.
[4]
2 “Other Expenses” include expenses of the Fund’s and Subsidiary’s most recent fiscal year.
[5]
3 The Adviser has agreed to reduce its advisory fee and/or reimburse the Fund so that Total Annual Fund Operating Expenses, excluding acquired fund fees and expenses (as applicable), certain investment related expenses, taxes, interest and other extraordinary expenses (including litigation), will not exceed 1.10% for Class I, 1.45% for Class A, 2.20% for Class C and 1.05% for Class R6. The fee waivers and/or expense reimbursements will continue for at least one year from the date of this Prospectus or until such time as the Board of Directors of Morgan Stanley Institutional Fund, Inc. (the “Company”) acts to discontinue all or a portion of such waivers and/or reimbursements when it deems such action is appropriate.
[6]
1 These returns do not reflect any tax consequences from a sale of your shares at the end of each period.
[7]
1 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 12 months, except for certain specific circumstances. See “Shareholder Information—How To Redeem Fund Shares” for further information about the CDSC waiver categories.
[8]
2 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.
[9]
2 Class C shares will generally automatically convert to Class A shares eight years after the end of the calendar month in which the shares were purchased. Performance for periods greater than eight years reflects this conversion.
[10]
2 The MSCI Emerging Markets Net Index is a free float-adjusted market capitalization weighted index that is designed to measure equity market performance of emerging markets. The term “free float” represents the portion of shares outstanding that are deemed to be available for purchase in the public equity markets by investors. The MSCI Emerging Markets Net Index currently consists of 24 emerging market country indices. The performance of the index is listed in U.S. dollars and assumes reinvestment of net dividends. Net total return indices reinvest dividends after the deduction of withholding taxes, using (for international indices) a tax rate applicable to non-resident institutional investors who do not benefit from double taxation treaties. It is not possible to invest directly in an index.
[11]
3 Since Inception reflects the inception date of the Fund.
[12]
1 “Advisory Fee” includes the management fee of a wholly-owned subsidiary of the Fund organized as a company under the laws of the Cayman Islands (the “Subsidiary”). The Fund’s “Adviser” and “Administrator,” Morgan Stanley Investment Management Inc., has agreed to waive or credit a portion of the advisory fee in an amount equal to the management fee paid to the Adviser by the Subsidiary.
[13]
2 “Other Expenses” include expenses of the Fund’s and Subsidiary’s most recent fiscal year.
[14]
3 The Adviser has agreed to reduce its advisory fee and/or reimburse the Fund so that Total Annual Fund Operating Expenses, excluding acquired fund fees and expenses (as applicable), certain investment related expenses, taxes, interest and other extraordinary expenses (including litigation), will not exceed 1.15% for Class I, 1.50% for Class A, 2.25% for Class C and 1.10% for Class R6. The fee waivers and/or expense reimbursements will continue for at least one year from the date of this Prospectus or until such time as the Board of Directors of Morgan Stanley Institutional Fund, Inc. (the “Company”) acts to discontinue all or a portion of such waivers and/or reimbursements when it deems such action is appropriate.
[15]
1 These returns do not reflect any tax consequences from a sale of your shares at the end of each period.
[16]
1 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 12 months, except for certain specific circumstances. See “Shareholder Information—How To Redeem Fund Shares” for further information about the CDSC waiver categories.
[17]
2 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.
[18]
1 Performance shown for the Fund’s Class I and Class L shares reflects the performance of the Class I and Class C shares, respectively, of the Predecessor Fund for periods prior to May 21, 2010.
[19]
4 The MSCI All Country World Net Index is a free float-adjusted market capitalization weighted index designed to measure the equity market performance of developed and emerging markets. The term “free float” represents the portion of shares outstanding that are deemed to be available for purchase in the public equity markets by investors. The performance of the index is listed in U.S. dollars and assumes reinvestment of net dividends. Net total return indices reinvest dividends after the deduction of withholding taxes, using (for international indices) a tax rate applicable to non-resident institutional investors who do not benefit from double taxation treaties. It is not possible to invest directly in an index.
[20]
5 Since Inception reflects the inception date of Class I.
[21]
1 “Advisory Fee” includes the management fee of a wholly-owned subsidiary of the Fund organized as a company under the laws of the Cayman Islands (the “Subsidiary”). The Fund’s “Adviser” and “Administrator,” Morgan Stanley Investment Management Inc., has agreed to waive or credit a portion of the advisory fee in an amount equal to the management fee paid to the Adviser by the Subsidiary.
[22]
3 “Other Expenses” include expenses of the Fund’s and Subsidiary’s most recent fiscal year.
[23]
2 These returns do not reflect any tax consequences from a sale of your shares at the end of each period.
[24]
1 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 12 months, except for certain specific circumstances. See “Shareholder Information—How To Redeem Fund Shares” for further information about the CDSC waiver categories.
[25]
2 The Fund’s “Distributor,” Morgan Stanley Distribution, Inc., has agreed to waive for at least one year the 12b-1 fee on Class L shares of the Fund to the extent it exceeds 0.30% of the average daily net assets of such shares on an annualized basis. This waiver will continue for at least one year from the date of this Prospectus or until such time as the Board of Directors of Morgan Stanley Institutional Fund Inc. (the “Company”) acts to discontinue all or a portion of such waiver when it deems such action is appropriate.
[26]
2 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.
[27]
3 Class C shares will generally automatically convert to Class A shares eight years after the end of the calendar month in which the shares were purchased. Performance for periods greater than eight years reflects this conversion.
[28]
3 The MSCI All Country World ex USA Net Index is a free float-adjusted market capitalization weighted index designed to measure the equity market performance of developed and emerging markets, excluding the United States. The term “free float” represents the portion of shares outstanding that are deemed to be available for purchase in the public equity markets by investors. The performance of the index is listed in U.S. dollars and assumes reinvestment of net dividends. Net total return indices reinvest dividends after the deduction of withholding taxes, using (for international indices) a tax rate applicable to non-resident institutional investors who do not benefit from double taxation treaties. It is not possible to invest directly in an index.
[29]
4 Since Inception reflects the inception date of Class I.
[30]
1 “Advisory Fee” includes the management fee of a wholly-owned subsidiary of the Fund organized as a company under the laws of the Cayman Islands (the “Subsidiary”). The Fund’s “Adviser” and “Administrator,” Morgan Stanley Investment Management Inc., has agreed to waive or credit a portion of the advisory fee in an amount equal to the management fee paid to the Adviser by the Subsidiary.
[31]
2 “Other Expenses” include expenses of the Fund’s and Subsidiary’s most recent fiscal year.
[32]
3 The Adviser has agreed to reduce its advisory fee and/or reimburse the Fund so that Total Annual Fund Operating Expenses, excluding acquired fund fees and expenses (as applicable), certain investment related expenses, taxes, interest and other extraordinary expenses (including litigation), will not exceed 1.00% for Class I, 1.35% for Class A, 1.85% for Class L, 2.10% for Class C and 0.95% for Class R6. The fee waivers and/or expense reimbursements will continue for at least one year from the date of this Prospectus or until such time as the Board of Directors of Morgan Stanley Institutional Fund, Inc. (the “Company”) acts to discontinue all or a portion of such waivers and/or reimbursements when it deems such action is appropriate.
[33]
1 These returns do not reflect any tax consequences from a sale of your shares at the end of each period.
[34]
1 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 12 months, except for certain specific circumstances. See “Shareholder Information—How To Redeem Fund Shares” for further information about the CDSC waiver categories.
[35]
2 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.
[36]
2 Class C shares will generally automatically convert to Class A shares eight years after the end of the calendar month in which the shares were purchased. Performance for periods greater than eight years reflects this conversion.
[37]
3 The MSCI All Country World ex USA Net Index is a free float-adjusted market capitalization weighted index designed to measure the equity market performance of developed and emerging markets, excluding the United States. The term “free float” represents the portion of shares outstanding that are deemed to be available for purchase in the public equity markets by investors. The performance of the index is listed in U.S. dollars and assumes reinvestment of net dividends. Net total return indices reinvest dividends after the deduction of withholding taxes, using (for international indices) a tax rate applicable to non-resident institutional investors who do not benefit from double taxation treaties. It is not possible to invest directly in an index.
[38]
4 Since Inception reflects the inception date of Class I.
[39]
1 “Advisory Fee” includes the management fee of a wholly-owned subsidiary of the Fund organized as a company under the laws of the Cayman Islands (the “Subsidiary”). The Fund’s “Adviser” and “Administrator,” Morgan Stanley Investment Management Inc., has agreed to waive or credit a portion of the advisory fee in an amount equal to the management fee paid to the Adviser by the Subsidiary.
[40]
2 “Other Expenses” include expenses of the Fund’s and Subsidiary’s most recent fiscal year.
[41]
3 The Adviser has agreed to reduce its advisory fee and/or reimburse the Fund so that Total Annual Fund Operating Expenses, excluding acquired fund fees and expenses (as applicable), certain investment related expenses, taxes, interest and other extraordinary expenses (including litigation), will not exceed 1.00% for Class I, 1.35% for Class A, 1.85% for Class L, 2.10% for Class C and 0.94% for Class R6. The fee waivers and/or expense reimbursements will continue for at least one year from the date of this Prospectus or until such time as the Board of Directors of Morgan Stanley Institutional Fund, Inc. (the “Company”)  acts to discontinue all or a portion of such waivers and/or reimbursements when it deems such action is appropriate.
[42]
1 These returns do not reflect any tax consequences from a sale of your shares at the end of each period.
[43]
1 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 12 months, except for certain specific circumstances. See “Shareholder Information—How To Redeem Fund Shares” for further information about the CDSC waiver categories.
[44]
2 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.
[45]
2 Class C shares will generally automatically convert to Class A shares eight years after the end of the calendar month in which the shares were purchased. Performance for periods greater than eight years reflects this conversion.