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    <rr:RiskReturnHeading contextRef="P02_01_2021To02_01_2021_S000006642MemberdeiLegalEntityAxis">Loomis Sayles High Income Opportunities Fund</rr:RiskReturnHeading>
    <rr:ObjectiveHeading contextRef="P02_01_2021To02_01_2021_S000006642MemberdeiLegalEntityAxis">INVESTMENT OBJECTIVE</rr:ObjectiveHeading>
    <rr:ObjectivePrimaryTextBlock contextRef="P02_01_2021To02_01_2021_S000006642MemberdeiLegalEntityAxis">The Fund&#x2019;s investment objective is high current income.</rr:ObjectivePrimaryTextBlock>
    <rr:ObjectiveSecondaryTextBlock contextRef="P02_01_2021To02_01_2021_S000006642MemberdeiLegalEntityAxis">Capital appreciation is the Fund&#x2019;s secondary objective.</rr:ObjectiveSecondaryTextBlock>
    <rr:ExpenseHeading contextRef="P02_01_2021To02_01_2021_S000006642MemberdeiLegalEntityAxis">FUND FEES &amp; EXPENSES</rr:ExpenseHeading>
    <rr:ExpenseNarrativeTextBlock contextRef="P02_01_2021To02_01_2021_S000006642MemberdeiLegalEntityAxis">&lt;div style="/* background-color:#FFFFFF; */padding-left:2pt;padding-top:1.75;padding-bottom:0;align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;text-align:left;"&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;The following table describes the fees and expenses that you may pay if you buy, hold, and sell shares of the Fund*. You may pay other fees, &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;such as brokerage commissions and other fees to financial intermediaries, which are not reflected in this table.&lt;/div&gt;&lt;/div&gt; &lt;div style="/* background-color:#FFFFFF; */padding-left:2pt;padding-top:5;padding-bottom:0;align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;text-align:left;"&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;The Fund does not impose a sales charge, a redemption fee or an exchange fee.&lt;/div&gt;&lt;/div&gt;</rr:ExpenseNarrativeTextBlock>
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    <rr:PortfolioTurnoverHeading contextRef="P02_01_2021To02_01_2021_S000006642MemberdeiLegalEntityAxis">Portfolio Turnover</rr:PortfolioTurnoverHeading>
    <rr:PortfolioTurnoverTextBlock contextRef="P02_01_2021To02_01_2021_S000006642MemberdeiLegalEntityAxis">&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;The Fund pays transaction costs, such as commissions, when it buys and sells securities (or &#x201c;turns over&#x201d; its portfolio). A higher&#160;portfolio &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;turnover rate may indicate higher transaction costs and may result in higher taxes for you if your Fund shares are held in&#160;a taxable account. &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund&#x2019;s performance.&#160;During its most &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;recently ended fiscal year, the Fund&#x2019;s portfolio turnover rate was &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;96%&#160;of the average value of&#160;its portfolio.&lt;/div&gt;</rr:PortfolioTurnoverTextBlock>
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    <rr:StrategyHeading contextRef="P02_01_2021To02_01_2021_S000006642MemberdeiLegalEntityAxis">INVESTMENTS, RISKS AND PERFORMANCEPrincipal Investment Strategies</rr:StrategyHeading>
    <rr:StrategyNarrativeTextBlock contextRef="P02_01_2021To02_01_2021_S000006642MemberdeiLegalEntityAxis">&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;Under normal market conditions, the Fund will invest substantially all of its assets, and may invest up to 100% of its assets, in high income &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;securities (&#x201c;High-Income Securities&#x201d;). High-Income Securities are fixed-income securities that Loomis Sayles believes have the potential to &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;generate relatively high levels of current income. High-Income Securities are often rated below investment-grade (below investment-grade &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;securities are sometimes referred to as &#x201c;high-yield securities&#x201d; or &#x201c;junk bonds&#x201d;). Below investment-grade fixed-income securities are rated &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;below investment-grade quality (i.e., none of the three major rating agencies (Moody&#x2019;s Investors Service, Inc., Fitch Investor Services, Inc. or &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;S&amp;amp;P&#x2019;s Global Ratings) have rated the securities in one of their respective top four rating categories). The Fund&#x2019;s fixed-income securities &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;investments may include unrated securities (securities that are not rated by a rating agency) if Loomis Sayles determines that the securities &lt;/div&gt; &lt;div style="/* background-color:#FFFFFF; */padding-left:2pt;padding-top:1pt;padding-bottom:0;align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:0pt;margin-bottom:0;text-align:left;"&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;are of comparable quality to rated securities that the Fund may purchase. The Fund may invest approximately 20% of its assets in &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;investment-grade fixed-income securities. The Fund may invest a portion of its assets in senior floating-rate loans made to U.S. and foreign &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;borrowers. A significant portion of the securities purchased by the Fund may be issued by smaller-capitalization companies. There is no &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;minimum rating for debt in which the Fund may invest.&lt;/div&gt;&lt;/div&gt; &lt;div style="/* background-color:#FFFFFF; */padding-left:2pt;padding-top:5;padding-bottom:0;align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;text-align:left;"&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;Under normal market conditions, the Fund may invest up to 40% of its assets in foreign securities, including emerging market securities. &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;The Fund may invest without limit in obligations of supranational entities (e.g., the World Bank).&#160;Although certain securities purchased by &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;the Fund may be issued by domestic companies incorporated outside of the United States, the Adviser does not consider these securities to &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;be foreign if the issuer is included in the U.S. fixed-income indices published by Bloomberg Barclays.&#160;The Fund may also invest in &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;derivatives, including swaps (including credit default swaps, in which one party agrees to make periodic payments to a counterparty in &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;exchange for the right to receive a payment in the event of a default of the underlying reference security), purchasing or selling options or &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;futures contracts to hedge interest rate risk.&lt;/div&gt;&lt;/div&gt; &lt;div style="/* background-color:#FFFFFF; */padding-left:2pt;padding-top:5;padding-bottom:0;align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;text-align:left;"&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;The Fund&#x2019;s investments may include, among other things, corporate debt securities, U.S. government obligations, U.S. dollar denominated &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;foreign securities, zero-coupon and pay-in-kind securities, loan assignments and participations, delayed funding loans and revolving credit &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;facilities, commercial paper, mortgage-backed securities, collateralized mortgage obligations, mortgage dollar rolls, collateralized debt and &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;loan obligations and other asset-backed securities, securities issued pursuant to Rule 144A under the Securities Act of 1933 (&#x201c;Rule 144A &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;securities&#x201d;), when-issued securities, municipal bonds, repurchase agreements, debt-linked and equity-linked securities, convertible securities, &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;preferred shares and illiquid securities.&lt;/div&gt;&lt;/div&gt; &lt;div style="/* background-color:#FFFFFF; */padding-left:2pt;padding-top:5;padding-bottom:0;align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;text-align:left;"&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;In deciding which High-Income Securities to buy and sell, Loomis Sayles will consider, among other things, the financial strength of the &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;issuer, yield, coupon rate, current interest rates, current valuations and comparisons of the level of risk associated with particular investments &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;with Loomis Sayles&#x2019; expectations concerning the potential return of those types of investments. As part of its investment approach, Loomis &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;Sayles generally seeks fixed-income securities of issuers whose credit profiles Loomis Sayles believes have the potential to stabilize or improve. &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;With respect to investments in foreign securities, Loomis Sayles will consider the global economic environment, and the economic &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;environment of the relevant country, taking into account factors such as GDP growth, inflation and other economic conditions, monetary &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;policy, fiscal policy, leadership and social stability.&lt;/div&gt;&lt;/div&gt; &lt;div style="/* background-color:#FFFFFF; */padding-left:2pt;padding-top:5;padding-bottom:0;align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;text-align:left;"&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;Loomis Sayles may invest significantly in securities whose price Loomis Sayles believes is more sensitive to events related to the underlying &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;issuer than to changes in general interest rates or overall market default rates.&lt;/div&gt;&lt;/div&gt; </rr:StrategyNarrativeTextBlock>
    <rr:RiskHeading contextRef="P02_01_2021To02_01_2021_S000006642MemberdeiLegalEntityAxis">Principal Risks</rr:RiskHeading>
    <rr:RiskNarrativeTextBlock contextRef="P02_01_2021To02_01_2021_S000006642MemberdeiLegalEntityAxis">&lt;div style="/* background-color:#FFFFFF; */padding-left:2pt;padding-top:1.75;padding-bottom:0;align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;text-align:left;"&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;The principal risks of investing in the Fund are summarized below. The Fund does not represent a complete investment program.&#160;You may lose money by investing in the Fund.&lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt; The significance of any specific risk to an investment in the Fund will vary over time, depending on &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;the composition of the Fund&#x2019;s portfolio, market conditions, and other factors. You should read all of the risk information presented below &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;carefully, because any one or more of these risks may result in losses to the Fund.&lt;/div&gt;&lt;/div&gt; &lt;div style="/* background-color:#FFFFFF; */padding-left:2pt;padding-top:5;padding-bottom:0;align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;text-align:left;"&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="font-weight:bold;display:inline;"&gt;Credit/Counterparty Risk&lt;/div&gt;&lt;/div&gt;&lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt; is the risk that the issuer or guarantor of a fixed-income security in which the Fund invests, or the counterparty &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;to a derivative or other transaction, will be unable or unwilling to make timely payments of interest or principal or to otherwise honor its &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;obligations. As a result, the Fund may sustain losses or be unable or delayed in its ability to realize gains. Senior loans and other floating rate &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;securities that are rated below investment-grade are considered predominantly speculative with respect to the ability of the issuer to make &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;timely principal and interest payments.&lt;/div&gt;&lt;/div&gt; &lt;div style="/* background-color:#FFFFFF; */padding-left:2pt;padding-top:5;padding-bottom:0;align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;text-align:left;"&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="font-weight:bold;display:inline;"&gt;Below Investment-Grade Fixed-Income Securities Risk&lt;/div&gt;&lt;/div&gt;&lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt; is the risk that the Fund&#x2019;s investments in below investment-grade fixed-income &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;securities may be subject to greater risks than other fixed-income securities, including being subject to greater levels of interest rate risk, &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;credit risk (including a greater risk of default) and liquidity risk. The ability of the issuer to make principal and interest payments is &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;predominantly speculative for below investment-grade fixed-income securities.&lt;/div&gt;&lt;/div&gt; &lt;div style="/* background-color:#FFFFFF; */padding-left:2pt;padding-top:5;padding-bottom:0;align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;text-align:left;"&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="font-weight:bold;display:inline;"&gt;Liquidity Risk&lt;/div&gt;&lt;/div&gt;&lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt; is the risk that the Fund may be unable to find a buyer for its investments when it seeks to sell them or to receive the price it &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;expects. Events that may lead to increased redemptions, such as market disruptions or increases in interest rates, may also negatively impact &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;the liquidity of the Fund&#x2019;s investments when it needs to dispose of them. If the Fund is forced to sell its investments at an unfavorable time &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;and/or under adverse conditions in order to meet redemption requests, such sales could negatively affect the Fund. Securities acquired in a &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;private placement, such as Rule 144A securities, are generally subject to&#160;significant liquidity risk because they are subject to strict restrictions &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;on resale and there may be no liquid secondary market or ready purchaser for such securities. Liquidity issues may also make it difficult to &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;value the Fund&#x2019;s investments.&lt;/div&gt;&lt;/div&gt; &lt;div style="/* background-color:#FFFFFF; */padding-left:2pt;padding-top:5;padding-bottom:0;align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;text-align:left;"&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="font-weight:bold;display:inline;"&gt;Market/Issuer Risk&lt;/div&gt;&lt;/div&gt;&lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt; is the risk that the market value of the Fund&#x2019;s investments will move up and down, sometimes rapidly and &lt;/div&gt;&lt;/div&gt; &lt;div style="/* background-color:#FFFFFF; */padding-left:2pt;padding-top:1pt;padding-bottom:0;align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:0pt;margin-bottom:0;text-align:left;"&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;unpredictably, based upon overall market and economic conditions, as well as a number of reasons that directly relate to the issuers of the &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;Fund&#x2019;s investments, such as management performance, financial condition and demand for the issuers&#x2019; goods and services.&lt;/div&gt;&lt;/div&gt; &lt;div style="/* background-color:#FFFFFF; */padding-left:2pt;padding-top:5;padding-bottom:0;align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;text-align:left;"&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="font-weight:bold;display:inline;"&gt;Interest Rate Risk&lt;/div&gt;&lt;/div&gt;&lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt; is the risk that the value of the Fund&#x2019;s investments will fall if interest rates rise. Generally, the value of fixed-income &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;securities rises when prevailing interest rates fall and falls when interest rates rise.&#160; Interest rate risk generally is greater for funds that invest in &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;fixed-income securities with relatively longer durations than for funds that invest in fixed-income securities with shorter durations. The &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;values of &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;zero-coupon securities, pay-in-kind bonds and securities with longer maturities are generally more sensitive to fluctuations in &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;interest rates than other fixed-income securities. In addition, an economic downturn or period of rising interest rates could adversely affect &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;the market&#160;for these securities and reduce the Fund&#x2019;s ability to sell them, negatively impacting the performance of the Fund. &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;Potential future &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;changes in government monetary policy may affect the level of interest rates.&lt;/div&gt;&lt;/div&gt; &lt;div style="/* background-color:#FFFFFF; */padding-left:2pt;padding-top:5;padding-bottom:0;align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;text-align:left;"&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="font-weight:bold;display:inline;"&gt;Currency Risk&lt;/div&gt;&lt;/div&gt;&lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt; is the risk that the value of the Fund&#x2019;s investments will fall as a result of changes in exchange rates. &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;The Fund may elect not &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;to hedge currency risk or may hedge imperfectly, which may cause the Fund to incur losses that would not have been incurred had the risk &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;been hedged.&lt;/div&gt;&lt;/div&gt; &lt;div style="/* background-color:#FFFFFF; */padding-left:2pt;padding-top:5;padding-bottom:0;align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;text-align:left;"&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="font-weight:bold;display:inline;"&gt;Cybersecurity and Technology Risk&lt;/div&gt;&lt;/div&gt;&lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt; is the risk associated with the increasing dependence of the Fund, its service providers, and other &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;market participants on complex information technology and communications systems. Such systems are subject to a number of different &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;threats and risks that could adversely affect the Fund and its shareholders. Cybersecurity and other operational and technology issues may &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;result in financial losses to the Fund and its shareholders.&lt;/div&gt;&lt;/div&gt; &lt;div style="/* background-color:#FFFFFF; */padding-left:2pt;padding-top:5;padding-bottom:0;align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;text-align:left;"&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="font-weight:bold;display:inline;"&gt;Derivatives Risk&lt;/div&gt;&lt;/div&gt;&lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt; is the risk that the value of the Fund&#x2019;s derivative investments such as&#160;&lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;options and futures transactions and swap &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;transactions&#160;will fall, for example, because of changes in the value of the underlying reference instruments, pricing difficulties or lack of &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;correlation with the underlying investments. The use of derivatives for other than hedging purposes may be considered a speculative activity, &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;and involves greater risks than are involved in hedging. There is also the risk that the Fund may be unable to terminate or sell a derivative &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;position at an advantageous time or price.&#160;&#160;The Fund&#x2019;s derivative counterparties may experience financial difficulties or otherwise be &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;unwilling or unable to honor their obligations, possibly resulting in losses to the Fund.&#160; This risk is greater for&#160;&lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt; uncleared swaps&#160;and other &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;over-the-counter (&#x201c;OTC&#x201d;) traded derivatives. Investing in derivatives gives rise to other risks, such as leverage risk, liquidity risk, &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;credit/counterparty risk, interest rate risk and market/issuer risk. The use of derivatives may cause the Fund to incur losses greater than those &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;which would have occurred had derivatives not been used.&lt;/div&gt;&lt;/div&gt; &lt;div style="/* background-color:#FFFFFF; */padding-left:2pt;padding-top:5;padding-bottom:0;align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;text-align:left;"&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="font-weight:bold;display:inline;"&gt;Emerging Markets Risk&lt;/div&gt;&lt;/div&gt;&lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt; is the risk that the Fund&#x2019;s investments in emerging markets may face greater foreign securities risk.&#160;Emerging &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;markets investments are subject to greater risks arising from political or economic instability, nationalization or confiscatory taxation, &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;currency exchange restrictions and an issuer&#x2019;s unwillingness or inability to make principal or interest payments on its obligations. Emerging &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;markets companies may be smaller and have shorter operating histories than companies in developed markets.&lt;/div&gt;&lt;/div&gt; &lt;div style="/* background-color:#FFFFFF; */padding-left:2pt;padding-top:5;padding-bottom:0;align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;text-align:left;"&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="font-weight:bold;display:inline;"&gt;Equity Securities Risk&lt;/div&gt;&lt;/div&gt;&lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt; is the risk that the value of the Fund&#x2019;s investments in equity securities could be subject to unpredictable declines in &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;the value of individual securities and periods of below-average performance in individual securities or in the equity market as a whole. In the &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;event an issuer is liquidated or declares bankruptcy, the claims of owners of the issuer&#x2019;s bonds generally take precedence over the claims of &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;those who own preferred stock or common stock.&lt;/div&gt;&lt;/div&gt; &lt;div style="/* background-color:#FFFFFF; */padding-left:2pt;padding-top:5;padding-bottom:0;align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;text-align:left;"&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="font-weight:bold;display:inline;"&gt;Foreign Securities Risk&lt;/div&gt;&lt;/div&gt;&lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt; is the risk that the value of the Fund&#x2019;s foreign investments will fall as a result of foreign political, social, economic, &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;environmental, credit, informational or currency changes or other issues relating to foreign investing generally. Foreign securities may be &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;subject to higher volatility than U.S. securities, varying degrees of regulation and limited liquidity. The Fund&#x2019;s investments in foreign &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;securities may be subject to foreign withholding or other taxes, which would decrease the yield on those securities.&lt;/div&gt;&lt;/div&gt; &lt;div style="/* background-color:#FFFFFF; */padding-left:2pt;padding-top:5;padding-bottom:0;align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;text-align:left;"&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="font-weight:bold;display:inline;"&gt;Inflation/Deflation Risk&lt;/div&gt;&lt;/div&gt;&lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt; is the risk that the value of assets or income from investments will be worth less in the future as inflation decreases &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;the present value of future payments. Deflation risk is the risk that prices throughout the economy decline over time - the opposite of &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;inflation. Deflation may have an adverse effect on the creditworthiness of issuers and may make issuer default more likely, which may result &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;in a decline in the value of the Fund&#x2019;s portfolio.&lt;/div&gt;&lt;/div&gt; &lt;div style="/* background-color:#FFFFFF; */padding-left:2pt;padding-top:5;padding-bottom:0;align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;text-align:left;"&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="font-weight:bold;display:inline;"&gt;Large Investor Risk&lt;/div&gt;&lt;/div&gt;&lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt; is the risk associated with ownership&#160;of shares of the Fund that may be concentrated in one or a few large investors. &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;Such investors may redeem shares in large quantities or on a frequent basis. Redemptions by a large investor can affect the performance of &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;the Fund, may increase realized capital gains, including short-term capital gains taxable as ordinary income, may accelerate the realization of &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;taxable income to shareholders and may increase transaction costs. These transactions potentially limit the use of any capital loss &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;carryforwards and certain other losses to offset future realized capital gains (if any). Such transactions may also increase the Fund&#x2019;s expenses.&lt;/div&gt;&lt;/div&gt; &lt;div style="/* background-color:#FFFFFF; */padding-left:2pt;padding-top:5;padding-bottom:0;align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;text-align:left;"&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="font-weight:bold;display:inline;"&gt;Leverage Risk&lt;/div&gt;&lt;/div&gt;&lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt; is the risk associated with securities or investment practices (e.g., borrowing and the use of certain derivatives) that multiply &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;small index, market or asset price movements into larger changes in value. Use of derivative instruments (such as futures and forward &lt;/div&gt;&lt;/div&gt;  &lt;div style="/* background-color:#FFFFFF; */padding-left:2pt;padding-top:1pt;padding-bottom:0;align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:0pt;margin-bottom:0;text-align:left;"&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;currency contracts) may involve leverage. When a derivative is used as a hedge against an offsetting position that the Fund also holds, &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;any&#160;gains generated by the derivative should be substantially offset by&#160;losses on the hedged instrument, and vice versa. To the extent that the &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;Fund uses a derivative for purposes other than as a hedge, or if the Fund hedges imperfectly, the Fund is directly exposed to the risks of that &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;derivative and any loss generated by the derivative will not be offset by a gain. The use of leverage increases the impact of gains and losses on &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;the Fund&#x2019;s returns, and may lead to significant losses if investments are not successful.&lt;/div&gt;&lt;/div&gt; &lt;div style="/* background-color:#FFFFFF; */padding-left:2pt;padding-top:5;padding-bottom:0;align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;text-align:left;"&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="font-weight:bold;display:inline;"&gt;Management Risk&lt;/div&gt;&lt;/div&gt;&lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt; is the risk that Loomis Sayles&#x2019; investment techniques will be unsuccessful and cause the Fund to incur losses.&lt;/div&gt;&lt;/div&gt; &lt;div style="/* background-color:#FFFFFF; */padding-left:2pt;padding-top:5;padding-bottom:0;align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;text-align:left;"&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="font-weight:bold;display:inline;"&gt;Mortgage-Related and Asset-Backed Securities Risk&lt;/div&gt;&lt;/div&gt;&lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt; is the risk associated with the&#160;mortgages and assets underlying the securities, as well &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;as the risk that the securities may be prepaid and result in the reinvestment of the prepaid amounts in securities with lower yields than the &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;prepaid obligations. Conversely, there is a risk that a rise in interest rates will extend the life of a mortgage-related or asset-backed security &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;beyond the expected prepayment time, typically reducing the security&#x2019;s value, which is called extension risk. The Fund may also incur a loss &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;when there is a prepayment of securities that were purchased at a premium. It also includes risks associated with investing in the mortgages &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;underlying the mortgage-backed securities.&#160;The Fund&#x2019;s investments in other asset-backed securities are subject to risks similar to those &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;associated with mortgage-related securities, as well as additional risks associated with the nature of the assets and the servicing of those assets. &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;The Fund&#x2019;s investments in mortgage-related and other asset-backed securities are also subject to the risks associated with investments in &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;fixed-income securities generally (e.g., credit/counterparty, liquidity and valuation risks).&lt;/div&gt;&lt;/div&gt; &lt;div style="/* background-color:#FFFFFF; */padding-left:2pt;padding-top:5;padding-bottom:0;align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;text-align:left;"&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="font-weight:bold;display:inline;"&gt;Small-Capitalization Companies Risk&lt;/div&gt;&lt;/div&gt;&lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt; is the risk that the Fund&#x2019;s investments may be subject to more abrupt price movements, limited &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;markets, increased volatility and less liquidity than investments in larger, more established companies, which could adversely affect the value &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;of the portfolio.&lt;/div&gt;&lt;/div&gt; </rr:RiskNarrativeTextBlock>
    <rr:RiskLoseMoney contextRef="P02_01_2021To02_01_2021_S000006642MemberdeiLegalEntityAxis">You may lose money by investing in the Fund.</rr:RiskLoseMoney>
    <rr:BarChartAndPerformanceTableHeading contextRef="P02_01_2021To02_01_2021_S000006642MemberdeiLegalEntityAxis">Risk/Return Bar Chart and Table</rr:BarChartAndPerformanceTableHeading>
    <rr:PerformanceNarrativeTextBlock contextRef="P02_01_2021To02_01_2021_S000006642MemberdeiLegalEntityAxis">&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;The following bar chart and table give an indication of the risks of investing in the Fund by showing changes in the Fund&#x2019;s performance from year to year and by showing how the Fund&#x2019;s average annual returns for the one-year, five-year and ten-year periods compare to those of a broad measure of market performance.&lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"/&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"/&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"/&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt; The Fund&#x2019;s past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future.&lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt; Updated performance information is available online at&#160;www.loomissayles.com and/or by &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;calling the Fund toll-free at 800-633-3330.&lt;/div&gt;</rr:PerformanceNarrativeTextBlock>
    <rr:PerformanceInformationIllustratesVariabilityOfReturns contextRef="P02_01_2021To02_01_2021_S000006642MemberdeiLegalEntityAxis">The following bar chart and table give an indication of the risks of investing in the Fund by showing changes in the Fund&#x2019;s performance from year to year and by showing how the Fund&#x2019;s average annual returns for the one-year, five-year and ten-year periods compare to those of a broad measure of market performance.</rr:PerformanceInformationIllustratesVariabilityOfReturns>
    <rr:PerformancePastDoesNotIndicateFuture contextRef="P02_01_2021To02_01_2021_S000006642MemberdeiLegalEntityAxis">The Fund&#x2019;s past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future.</rr:PerformancePastDoesNotIndicateFuture>
    <rr:PerformanceAvailabilityWebSiteAddress contextRef="P02_01_2021To02_01_2021_S000006642MemberdeiLegalEntityAxis">www.loomissayles.com</rr:PerformanceAvailabilityWebSiteAddress>
    <rr:PerformanceAvailabilityPhone contextRef="P02_01_2021To02_01_2021_S000006642MemberdeiLegalEntityAxis">800-633-3330</rr:PerformanceAvailabilityPhone>
    <rr:BarChartHeading contextRef="P02_01_2021To02_01_2021_S000006642MemberdeiLegalEntityAxis">Total Returns for Institutional Class Shares</rr:BarChartHeading>
    <rr:BarChartClosingTextBlock contextRef="P02_01_2021To02_01_2021_S000006642MemberdeiLegalEntityAxis">&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px; white-space: nowrap;;display:inline;"&gt;Highest Quarterly Return:&lt;/div&gt;&lt;br/&gt; &lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px; white-space: nowrap;;display:inline;"&gt;&lt;span style="-sec-ix-hidden:hidden3215136"&gt;Second Quarter 2020&lt;/span&gt;, &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px; white-space: nowrap;;display:inline;"&gt;9.87%&lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px; white-space: nowrap;;display:inline;"/&gt;&lt;br/&gt; &lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 8.02pt; letter-spacing: 0px; top: 0px; white-space: nowrap;;display:inline;"&gt;&#160;&lt;/div&gt;&lt;br/&gt; &lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px; white-space: nowrap;;display:inline;"&gt;Lowest Quarterly Return:&lt;/div&gt;&lt;br/&gt; &lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px; white-space: nowrap;;display:inline;"&gt;&lt;span style="-sec-ix-hidden:hidden3215137"&gt;First Quarter 2020&lt;/span&gt;, &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px; white-space: nowrap;;display:inline;"&gt;-12.05%&lt;/div&gt;</rr:BarChartClosingTextBlock>
    <rr:HighestQuarterlyReturnLabel contextRef="P02_01_2021To02_01_2021_C000018129MemberrrProspectusShareClassAxis_S000006642MemberdeiLegalEntityAxis">Highest Quarterly Return:</rr:HighestQuarterlyReturnLabel>
    <rr:BarChartHighestQuarterlyReturn
      contextRef="P02_01_2021To02_01_2021_C000018129MemberrrProspectusShareClassAxis_S000006642MemberdeiLegalEntityAxis"
      decimals="INF"
      unitRef="Unit_pure">0.0987</rr:BarChartHighestQuarterlyReturn>
    <rr:LowestQuarterlyReturnLabel contextRef="P02_01_2021To02_01_2021_C000018129MemberrrProspectusShareClassAxis_S000006642MemberdeiLegalEntityAxis">Lowest Quarterly Return:</rr:LowestQuarterlyReturnLabel>
    <rr:BarChartLowestQuarterlyReturn
      contextRef="P02_01_2021To02_01_2021_C000018129MemberrrProspectusShareClassAxis_S000006642MemberdeiLegalEntityAxis"
      decimals="INF"
      unitRef="Unit_pure">-0.1205</rr:BarChartLowestQuarterlyReturn>
    <rr:PerformanceTableHeading contextRef="P02_01_2021To02_01_2021_S000006642MemberdeiLegalEntityAxis">Average Annual Total Returns (for the periods ended December 31, 2020) </rr:PerformanceTableHeading>
    <rr:AverageAnnualReturnYear01
      contextRef="P02_01_2021To02_01_2021_C000018129MemberrrProspectusShareClassAxis_S000006642MemberdeiLegalEntityAxis"
      decimals="INF"
      unitRef="Unit_pure">0.0924</rr:AverageAnnualReturnYear01>
    <rr:AverageAnnualReturnYear05
      contextRef="P02_01_2021To02_01_2021_C000018129MemberrrProspectusShareClassAxis_S000006642MemberdeiLegalEntityAxis"
      decimals="INF"
      unitRef="Unit_pure">0.0871</rr:AverageAnnualReturnYear05>
    <rr:AverageAnnualReturnYear10
      contextRef="P02_01_2021To02_01_2021_C000018129MemberrrProspectusShareClassAxis_S000006642MemberdeiLegalEntityAxis"
      decimals="INF"
      unitRef="Unit_pure">0.0742</rr:AverageAnnualReturnYear10>
    <rr:AverageAnnualReturnYear01
      contextRef="P02_01_2021To02_01_2021_AfterTaxesOnDistributionsMemberrrPerformanceMeasureAxis_C000018129MemberrrProspectusShareClassAxis_S000006642MemberdeiLegalEntityAxis"
      decimals="INF"
      unitRef="Unit_pure">0.0666</rr:AverageAnnualReturnYear01>
    <rr:AverageAnnualReturnYear05
      contextRef="P02_01_2021To02_01_2021_AfterTaxesOnDistributionsMemberrrPerformanceMeasureAxis_C000018129MemberrrProspectusShareClassAxis_S000006642MemberdeiLegalEntityAxis"
      decimals="INF"
      unitRef="Unit_pure">0.0601</rr:AverageAnnualReturnYear05>
    <rr:AverageAnnualReturnYear10
      contextRef="P02_01_2021To02_01_2021_AfterTaxesOnDistributionsMemberrrPerformanceMeasureAxis_C000018129MemberrrProspectusShareClassAxis_S000006642MemberdeiLegalEntityAxis"
      decimals="INF"
      unitRef="Unit_pure">0.0476</rr:AverageAnnualReturnYear10>
    <rr:AverageAnnualReturnYear01
      contextRef="P02_01_2021To02_01_2021_AfterTaxesOnDistributionsAndSalesMemberrrPerformanceMeasureAxis_C000018129MemberrrProspectusShareClassAxis_S000006642MemberdeiLegalEntityAxis"
      decimals="INF"
      unitRef="Unit_pure">0.0536</rr:AverageAnnualReturnYear01>
    <rr:AverageAnnualReturnYear05
      contextRef="P02_01_2021To02_01_2021_AfterTaxesOnDistributionsAndSalesMemberrrPerformanceMeasureAxis_C000018129MemberrrProspectusShareClassAxis_S000006642MemberdeiLegalEntityAxis"
      decimals="INF"
      unitRef="Unit_pure">0.0552</rr:AverageAnnualReturnYear05>
    <rr:AverageAnnualReturnYear10
      contextRef="P02_01_2021To02_01_2021_AfterTaxesOnDistributionsAndSalesMemberrrPerformanceMeasureAxis_C000018129MemberrrProspectusShareClassAxis_S000006642MemberdeiLegalEntityAxis"
      decimals="INF"
      unitRef="Unit_pure">0.0458</rr:AverageAnnualReturnYear10>
    <rr:AverageAnnualReturnYear01
      contextRef="P02_01_2021To02_01_2021_BloombergBarclaysUsCorporateHighyieldBondIndexMemberrrPerformanceMeasureAxis_S000006642MemberdeiLegalEntityAxis"
      decimals="INF"
      unitRef="Unit_pure">0.0711</rr:AverageAnnualReturnYear01>
    <rr:AverageAnnualReturnYear05
      contextRef="P02_01_2021To02_01_2021_BloombergBarclaysUsCorporateHighyieldBondIndexMemberrrPerformanceMeasureAxis_S000006642MemberdeiLegalEntityAxis"
      decimals="INF"
      unitRef="Unit_pure">0.0859</rr:AverageAnnualReturnYear05>
    <rr:AverageAnnualReturnYear10
      contextRef="P02_01_2021To02_01_2021_BloombergBarclaysUsCorporateHighyieldBondIndexMemberrrPerformanceMeasureAxis_S000006642MemberdeiLegalEntityAxis"
      decimals="INF"
      unitRef="Unit_pure">0.0680</rr:AverageAnnualReturnYear10>
    <rr:PerformanceTableNarrativeTextBlock contextRef="P02_01_2021To02_01_2021_S000006642MemberdeiLegalEntityAxis">&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the&#160;impact of state and local taxes. Actual after-tax returns depend on an investor&#x2019;s tax situation and may differ from those shown.&#160;After-tax returns shown are &lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;not relevant to investors who hold their shares through tax-advantaged arrangements, such as 401(k)&#160;plans, qualified plans, education &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;savings accounts, such as 529 plans, or individual retirement accounts. &lt;/div&gt; &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;Index performance&#160;reflects no deduction for fees, expenses or taxes.&lt;/div&gt;</rr:PerformanceTableNarrativeTextBlock>
    <rr:PerformanceTableUsesHighestFederalRate contextRef="P02_01_2021To02_01_2021_S000006642MemberdeiLegalEntityAxis">After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the&#160;impact of state and local taxes.</rr:PerformanceTableUsesHighestFederalRate>
    <rr:PerformanceTableNotRelevantToTaxDeferred contextRef="P02_01_2021To02_01_2021_S000006642MemberdeiLegalEntityAxis">Actual after-tax returns depend on an investor&#x2019;s tax situation and may differ from those shown.&#160;After-tax returns shown are not relevant to investors who hold their shares through tax-advantaged arrangements, such as 401(k)&#160;plans, qualified plans, education savings accounts, such as 529 plans, or individual retirement accounts. </rr:PerformanceTableNotRelevantToTaxDeferred>
    <rr:RiskReturnHeading contextRef="P02_01_2021To02_01_2021_S000006639MemberdeiLegalEntityAxis">Loomis Sayles Securitized Asset Fund</rr:RiskReturnHeading>
    <rr:ObjectiveHeading contextRef="P02_01_2021To02_01_2021_S000006639MemberdeiLegalEntityAxis">INVESTMENT OBJECTIVE</rr:ObjectiveHeading>
    <rr:ObjectivePrimaryTextBlock contextRef="P02_01_2021To02_01_2021_S000006639MemberdeiLegalEntityAxis">&lt;div style="/* background-color:#FFFFFF; */padding-left:2pt;padding-top:1.75;padding-bottom:0;align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;text-align:left;"&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;The Fund&#x2019;s investment objective is to seek a high level of current income consistent with capital preservation.&lt;/div&gt;&lt;/div&gt;</rr:ObjectivePrimaryTextBlock>
    <rr:ExpenseHeading contextRef="P02_01_2021To02_01_2021_S000006639MemberdeiLegalEntityAxis">FUND FEES &amp; EXPENSES</rr:ExpenseHeading>
    <rr:ExpenseNarrativeTextBlock contextRef="P02_01_2021To02_01_2021_S000006639MemberdeiLegalEntityAxis">&lt;div style="/* background-color:#FFFFFF; */padding-left:2pt;padding-top:1.75;padding-bottom:0;align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;text-align:left;"&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;The following table describes the fees and expenses that you may pay if you buy, hold, and sell shares of the Fund*. You may pay other fees, &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;such as brokerage commissions and other fees to financial intermediaries, which are not reflected in this table.&lt;/div&gt;&lt;/div&gt; &lt;div style="/* background-color:#FFFFFF; */padding-left:2pt;padding-top:5;padding-bottom:0;align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;text-align:left;"&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;The Fund does not impose a sales charge, a redemption fee or an exchange fee.&lt;/div&gt;&lt;/div&gt;</rr:ExpenseNarrativeTextBlock>
    <rr:OperatingExpensesCaption contextRef="P02_01_2021To02_01_2021_S000006639MemberdeiLegalEntityAxis">Annual Fund Operating Expenses&#160;(expenses that you pay each year as a percentage of the value of your investment)</rr:OperatingExpensesCaption>
    <rr:ManagementFeesOverAssets
      contextRef="P02_01_2021To02_01_2021_C000018125MemberrrProspectusShareClassAxis_S000006639MemberdeiLegalEntityAxis"
      decimals="INF"
      id="Fact_3215159"
      unitRef="Unit_pure">0.0000</rr:ManagementFeesOverAssets>
    <rr:DistributionAndService12b1FeesOverAssets
      contextRef="P02_01_2021To02_01_2021_C000018125MemberrrProspectusShareClassAxis_S000006639MemberdeiLegalEntityAxis"
      decimals="INF"
      id="Fact_3215160"
      unitRef="Unit_pure">0.0000</rr:DistributionAndService12b1FeesOverAssets>
    <rr:OtherExpensesOverAssets
      contextRef="P02_01_2021To02_01_2021_C000018125MemberrrProspectusShareClassAxis_S000006639MemberdeiLegalEntityAxis"
      decimals="INF"
      id="Fact_3215161"
      unitRef="Unit_pure">0.0000</rr:OtherExpensesOverAssets>
    <rr:ExpensesOverAssets
      contextRef="P02_01_2021To02_01_2021_C000018125MemberrrProspectusShareClassAxis_S000006639MemberdeiLegalEntityAxis"
      decimals="INF"
      id="Fact_3215162"
      unitRef="Unit_pure">0.0000</rr:ExpensesOverAssets>
    <rr:ExpenseExampleHeading contextRef="P02_01_2021To02_01_2021_S000006639MemberdeiLegalEntityAxis">Example</rr:ExpenseExampleHeading>
    <rr:ExpenseExampleNarrativeTextBlock contextRef="P02_01_2021To02_01_2021_S000006639MemberdeiLegalEntityAxis">&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;The example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.&#160;The &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at&#160;the end of those &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;periods. The example also assumes that your investment has a 5% return each year and that the Fund&#x2019;s operating&#160;expenses remain the same&lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;. &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;The example does not take into account brokerage commissions and other fees to financial intermediaries that you may pay on your &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;purchases and sales of shares of the Fund. Although your actual costs may be higher or lower, based on these assumptions your costs would &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;be:&lt;/div&gt;</rr:ExpenseExampleNarrativeTextBlock>
    <rr:ExpenseExampleYear01
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      decimals="0"
      unitRef="Unit_USD">0</rr:ExpenseExampleYear01>
    <rr:ExpenseExampleYear03
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      decimals="0"
      unitRef="Unit_USD">0</rr:ExpenseExampleYear03>
    <rr:ExpenseExampleYear05
      contextRef="P02_01_2021To02_01_2021_C000018125MemberrrProspectusShareClassAxis_S000006639MemberdeiLegalEntityAxis"
      decimals="0"
      unitRef="Unit_USD">0</rr:ExpenseExampleYear05>
    <rr:ExpenseExampleYear10
      contextRef="P02_01_2021To02_01_2021_C000018125MemberrrProspectusShareClassAxis_S000006639MemberdeiLegalEntityAxis"
      decimals="0"
      unitRef="Unit_USD">0</rr:ExpenseExampleYear10>
    <rr:PortfolioTurnoverHeading contextRef="P02_01_2021To02_01_2021_S000006639MemberdeiLegalEntityAxis">Portfolio Turnover</rr:PortfolioTurnoverHeading>
    <rr:PortfolioTurnoverTextBlock contextRef="P02_01_2021To02_01_2021_S000006639MemberdeiLegalEntityAxis">&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;The Fund pays transaction costs, such as commissions, when it buys and sells securities (or &#x201c;turns over&#x201d; its portfolio). A higher&#160;portfolio &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;turnover rate may indicate higher transaction costs and may result in higher taxes for you if your Fund shares are held in&#160;a taxable account. &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund&#x2019;s performance.&#160;During its most &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;recently ended fiscal year, the Fund&#x2019;s portfolio turnover rate was &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;283%&#160;of the average value of&#160;its portfolio.&lt;/div&gt;</rr:PortfolioTurnoverTextBlock>
    <rr:PortfolioTurnoverRate
      contextRef="P02_01_2021To02_01_2021_S000006639MemberdeiLegalEntityAxis"
      decimals="INF"
      unitRef="Unit_pure">2.83</rr:PortfolioTurnoverRate>
    <rr:StrategyHeading contextRef="P02_01_2021To02_01_2021_S000006639MemberdeiLegalEntityAxis">INVESTMENTS, RISKS AND PERFORMANCE&#160;Principal Investment Strategies</rr:StrategyHeading>
    <rr:StrategyNarrativeTextBlock contextRef="P02_01_2021To02_01_2021_S000006639MemberdeiLegalEntityAxis">&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;Under normal market conditions, the Fund will invest at least 80% of its net assets (plus any borrowings made for investment purposes) in a &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;diversified portfolio of securitized assets, such as mortgage-backed and other asset-backed securities.&#160;The Fund may invest in asset-backed &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;securities of any type, including residential and commercial asset-backed securities, asset-backed securities related to automobiles, credit &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;cards, home equity loans, manufactured housing, utilities, and other miscellaneous asset-backed securities. The Fund may only buy &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;securities that are rated investment-grade at the time of purchase by at least one of the three major rating agencies (Moody&#x2019;s Investors &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;Service, Inc., Fitch Investor Services, Inc.&#160;or S&amp;amp;P Global Ratings) or, if unrated, are determined by Loomis Sayles to be of comparable &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;quality. It is expected that a majority of the Fund&#x2019;s securities will be rated AAA or Aaa by at least one of the rating agencies at the time of &lt;/div&gt; &lt;div style="/* background-color:#FFFFFF; */padding-left:2pt;padding-top:1pt;padding-bottom:0;align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:0pt;margin-bottom:0;text-align:left;"&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;purchase. The Fund may continue to hold securities that are downgraded in credit rating subsequent to their purchase if Loomis Sayles &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;believes it would be advantageous to do so.&lt;/div&gt;&lt;/div&gt; &lt;div style="/* background-color:#FFFFFF; */padding-left:2pt;padding-top:5;padding-bottom:0;align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;text-align:left;"&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;The Fund may, without limitation, seek to obtain market exposure to the securities in which it primarily invests by entering into a series of &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;purchase and sale contracts (including on a &#x201c;to be announced&#x201d; basis) or by using investment techniques such as buybacks and dollar rolls.&#160;&lt;/div&gt;&lt;/div&gt; &lt;div style="/* background-color:#FFFFFF; */padding-left:2pt;padding-top:5;padding-bottom:0;align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;text-align:left;"&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;Loomis Sayles uses a bottom-up, fundamental research process to select individual securities for the Fund. The decision to buy or sell a &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;particular security is largely driven by Loomis Sayles&#x2019; view of the fundamentals of the issue compared to the prevailing market valuation, &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;which may be higher (suggesting a potential sell decision) or lower (suggesting a potential buy decision). Loomis Sayles also may seek to &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;construct a portfolio with risk characteristics similar, but not identical to, certain of the securities in the Bloomberg Barclays U.S. Securitized &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;Bond Index (the &#x201c;Index&#x201d;). Examples of typical risk characteristics that Loomis Sayles might consider include average life, credit quality, &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;effective duration, yield curve exposure and sector exposure. The portfolio will not necessarily exhibit similarities with the Index for some or &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;all risk characteristics. It is currently anticipated that the Fund&#x2019;s effective duration will be within +/- 1 year of the effective duration of the &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;Index.&lt;/div&gt;&lt;/div&gt; &lt;div style="/* background-color:#FFFFFF; */padding-left:2pt;padding-top:5;padding-bottom:0;align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;text-align:left;"&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;In deciding which securities to buy and sell, Loomis Sayles will consider, among other things, the financial strength of the issuer, current &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;interest rates, current valuations, Loomis Sayles&#x2019; expectations regarding future changes in interest rates and comparisons of the level of risk &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;associated with particular investments with Loomis Sayles&#x2019; expectations concerning the potential return of those investments.&lt;/div&gt;&lt;/div&gt; &lt;div style="/* background-color:#FFFFFF; */padding-left:2pt;padding-top:5;padding-bottom:0;align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;text-align:left;"&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;The Fund&#x2019;s investments may also include, among other things, the following: fixed and floating-rate instruments, mortgage pass-through &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;securities issued or guaranteed by agencies or instrumentalities of the U.S. government, collateralized mortgage obligations, commercial &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;mortgage-backed securities, mortgage-related asset-backed securities, other collateralized asset-backed securities, securities issued pursuant to &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;Rule 144A under the Securities Act of 1933 (&#x201c;Rule 144A Securities&#x201d;), U.S. government securities, corporate debt securities, zero-coupon &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;securities, step coupon securities, commercial paper, structured notes, other mortgage-related securities (including adjustable rate mortgage &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;securities, stripped mortgage-backed securities and mortgage dollar rolls), when-issued securities and repurchase agreements. The Fund may &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;also invest in options, futures and&#160;swaps (including credit default swaps, in which one party agrees to make periodic payments to a &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;counterparty in exchange for the right to receive a payment in the event of a default of the underlying reference security).&lt;/div&gt;&lt;/div&gt; &lt;div style="/* background-color:#FFFFFF; */padding-left:2pt;padding-top:5;padding-bottom:0;align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;text-align:left;"&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;The Fund may also engage in active and frequent trading of securities. Frequent trading may produce a high level of taxable gains, including &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;short-term capital gains taxable as ordinary income, as well as increased trading costs, which may lower the Fund&#x2019;s return.&lt;/div&gt;&lt;/div&gt; </rr:StrategyNarrativeTextBlock>
    <rr:RiskHeading contextRef="P02_01_2021To02_01_2021_S000006639MemberdeiLegalEntityAxis">Principal Risks</rr:RiskHeading>
    <rr:RiskNarrativeTextBlock contextRef="P02_01_2021To02_01_2021_S000006639MemberdeiLegalEntityAxis">&lt;div style="/* background-color:#FFFFFF; */padding-left:2pt;padding-top:1.75;padding-bottom:0;align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;text-align:left;"&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;The principal risks of investing in the Fund are summarized below. The Fund does not represent a complete investment program.&#160;You may lose money by investing in the Fund. &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt; The significance of any specific risk to an investment in the Fund will vary over time, depending on &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;the composition of the Fund&#x2019;s portfolio, market conditions, and other factors. You should read all of the risk information presented below &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;carefully, because any one or more of these risks may result in losses to the Fund.&lt;/div&gt;&lt;/div&gt; &lt;div style="/* background-color:#FFFFFF; */padding-left:2pt;padding-top:5;padding-bottom:0;align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;text-align:left;"&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="font-weight:bold;display:inline;"&gt;Interest Rate Risk&lt;/div&gt;&lt;/div&gt;&lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt; is the risk that the value of the Fund&#x2019;s investments will fall if interest rates rise. Generally, the value of fixed-income &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;securities rises when prevailing interest rates fall and falls when interest rates rise.&#160; Interest rate risk generally is greater for funds that invest in &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;fixed-income securities with relatively longer durations than for funds that invest in fixed-income securities with shorter durations. The &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;values of &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;zero-coupon securities and securities with longer maturities are generally more sensitive to fluctuations in interest rates than other &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;fixed-income securities. In addition, an economic downturn or period of rising interest rates could adversely affect the market&#160;for these &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;securities and reduce the Fund&#x2019;s ability to sell them, negatively impacting the performance of the Fund. &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;Potential future changes in &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;government monetary policy may affect the level of interest rates.&lt;/div&gt;&lt;/div&gt; &lt;div style="/* background-color:#FFFFFF; */padding-left:2pt;padding-top:5;padding-bottom:0;align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;text-align:left;"&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="font-weight:bold;display:inline;"&gt;Mortgage-Related and Asset-Backed Securities Risk&lt;/div&gt;&lt;/div&gt;&lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt; is the risk associated with the&#160;mortgages and assets underlying the securities, as well &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;as the risk that the securities may be prepaid and result in the reinvestment of the prepaid amounts in securities with lower yields than the &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;prepaid obligations. Conversely, there is a risk that a rise in interest rates will extend the life of a mortgage-related or asset-backed security &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;beyond the expected prepayment time, typically reducing the security&#x2019;s value, which is called extension risk. The Fund may also incur a loss &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;when there is a prepayment of securities that were purchased at a premium. It also includes risks associated with investing in the mortgages &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;underlying the mortgage-backed securities.&#160;The Fund&#x2019;s investments in other asset-backed securities are subject to risks similar to those &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;associated with mortgage-related securities, as well as additional risks associated with the nature of the assets and the servicing of those assets. &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;The Fund&#x2019;s investments in mortgage-related and other asset-backed securities are also subject to the risks associated with investments in &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;fixed-income securities generally (e.g., credit/counterparty, liquidity and valuation risks).&lt;/div&gt;&lt;/div&gt; &lt;div style="/* background-color:#FFFFFF; */padding-left:2pt;padding-top:5;padding-bottom:0;align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;text-align:left;"&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="font-weight:bold;display:inline;"&gt;Cybersecurity and Technology Risk&lt;/div&gt;&lt;/div&gt;&lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt; is the risk associated with the increasing dependence of the Fund, its service providers, and other &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;market participants on complex information technology and communications systems. Such systems are subject to a number of different &lt;/div&gt;&lt;/div&gt; &lt;div style="/* background-color:#FFFFFF; */padding-left:2pt;padding-top:1pt;padding-bottom:0;align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:0pt;margin-bottom:0;text-align:left;"&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;threats and risks that could adversely affect the Fund and its shareholders. Cybersecurity and other operational and technology issues may &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;result in financial losses to the Fund and its shareholders.&lt;/div&gt;&lt;/div&gt; &lt;div style="/* background-color:#FFFFFF; */padding-left:2pt;padding-top:5;padding-bottom:0;align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;text-align:left;"&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="font-weight:bold;display:inline;"&gt;Derivatives Risk&lt;/div&gt;&lt;/div&gt;&lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt; is the risk that the value of the Fund&#x2019;s derivative investments such as&#160;&lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;structured notes, options, futures transactions and &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;swap transactions&#160;will fall, for example, because of changes in the value of the underlying reference instruments, pricing difficulties or lack of &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;correlation with the underlying investments. The use of derivatives for other than hedging purposes may be considered a speculative activity, &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;and involves greater risks than are involved in hedging. There is also the risk that the Fund may be unable to terminate or sell a derivative &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;position at an advantageous time or price.&#160;&#160;The Fund&#x2019;s derivative counterparties may experience financial difficulties or otherwise be &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;unwilling or unable to honor their obligations, possibly resulting in losses to the Fund.&#160; This risk is greater for&#160;&lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;uncleared swaps&#160;and other &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;over-the-counter (&#x201c;OTC&#x201d;) traded derivatives. Investing in derivatives gives rise to other risks, such as leverage risk, liquidity risk, &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;credit/counterparty risk, interest rate risk and market/issuer risk. The use of derivatives may cause the Fund to incur losses greater than those &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;which would have occurred had derivatives not been used.&lt;/div&gt;&lt;/div&gt; &lt;div style="/* background-color:#FFFFFF; */padding-left:2pt;padding-top:5;padding-bottom:0;align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;text-align:left;"&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="font-weight:bold;display:inline;"&gt;Leverage Risk&lt;/div&gt;&lt;/div&gt;&lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt; is the risk associated with securities or investment practices (e.g., borrowing and the use of certain derivatives) that multiply &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;small index, market or asset price movements into larger changes in value. Use of derivative instruments (such as futures and forward &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;currency contracts) may involve leverage. When a derivative is used as a hedge against an offsetting position that the Fund also holds, &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;any&#160;gains generated by the derivative should be substantially offset by&#160;losses on the hedged instrument, and vice versa. To the extent that the &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;Fund uses a derivative for purposes other than as a hedge, or if the Fund hedges imperfectly, the Fund is directly exposed to the risks of that &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;derivative and any loss generated by the derivative will not be offset by a gain. The use of leverage increases the impact of gains and losses on &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;the Fund&#x2019;s returns, and may lead to significant losses if investments are not successful.&lt;/div&gt;&lt;/div&gt; &lt;div style="/* background-color:#FFFFFF; */padding-left:2pt;padding-top:5;padding-bottom:0;align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;text-align:left;"&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="font-weight:bold;display:inline;"&gt;Credit/Counterparty Risk&lt;/div&gt;&lt;/div&gt;&lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt; is the risk that the issuer or guarantor of a fixed-income security in which the Fund invests, or the counterparty &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;to a derivative or other transaction, will be unable or unwilling to make timely payments of interest or principal or to otherwise honor its &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;obligations. As a result, the Fund may sustain losses or be unable or delayed in its ability to realize gains.&#160;&lt;/div&gt;&lt;/div&gt; &lt;div style="/* background-color:#FFFFFF; */padding-left:2pt;padding-top:5;padding-bottom:0;align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;text-align:left;"&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="font-weight:bold;display:inline;"&gt;Inflation/Deflation Risk&lt;/div&gt;&lt;/div&gt;&lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt; is the risk that the value of assets or income from investments will be worth less in the future as inflation decreases &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;the present value of future payments. Deflation risk is the risk that prices throughout the economy decline over time - the opposite of &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;inflation. Deflation may have an adverse effect on the creditworthiness of issuers and may make issuer default more likely, which may result &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;in a decline in the value of the Fund&#x2019;s portfolio.&lt;/div&gt;&lt;/div&gt; &lt;div style="/* background-color:#FFFFFF; */padding-left:2pt;padding-top:5;padding-bottom:0;align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;text-align:left;"&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="font-weight:bold;display:inline;"&gt;Large Investor Risk&lt;/div&gt;&lt;/div&gt;&lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt; is the risk associated with ownership&#160;of shares of the Fund that may be concentrated in one or a few large investors. &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;Such investors may redeem shares in large quantities or on a frequent basis. Redemptions by a large investor can affect the performance of &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;the Fund, may increase realized capital gains, including short-term capital gains taxable as ordinary income, may accelerate the realization of &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;taxable income to shareholders and may increase transaction costs. These transactions potentially limit the use of any capital loss &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;carryforwards and certain other losses to offset future realized capital gains (if any). Such transactions may also increase the Fund&#x2019;s expenses.&lt;/div&gt;&lt;/div&gt; &lt;div style="/* background-color:#FFFFFF; */padding-left:2pt;padding-top:5;padding-bottom:0;align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;text-align:left;"&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="font-weight:bold;display:inline;"&gt;LIBOR Risk&lt;/div&gt;&lt;/div&gt;&lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt; is the risk that the transition away from the London Interbank Offered Rate (&#x201c;LIBOR&#x201d;) may lead to increased volatility and &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;illiquidity in markets that are tied to LIBOR. LIBOR is a benchmark interest rate that is used extensively as a &#x201c;reference rate&#x201d; for financial &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;instruments, including many corporate and municipal bonds, senior loans, asset-backed and mortgage-related securities, interest rate swaps &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;and other derivatives. Additionally, the Fund may borrow money at rates that are based on LIBOR. In July 2017, the head of the United &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;Kingdom Financial Conduct Authority, the agency that oversees LIBOR, announced that after 2021 it will cease its active encouragement &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;of banks to provide the quotations needed to sustain LIBOR. That announcement suggests that LIBOR may cease to be published after that &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;time. The transition away from LIBOR poses a number of other risks, including changed values of LIBOR-related investments and reduced &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;effectiveness of hedging strategies, each of which may adversely affect the Fund&#x2019;s performance.&lt;/div&gt;&lt;/div&gt; &lt;div style="/* background-color:#FFFFFF; */padding-left:2pt;padding-top:5;padding-bottom:0;align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;text-align:left;"&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="font-weight:bold;display:inline;"&gt;Liquidity Risk&lt;/div&gt;&lt;/div&gt;&lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt; is the risk that the Fund may be unable to find a buyer for its investments when it seeks to sell them or to receive the price it &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;expects. Events that may lead to increased redemptions, such as market disruptions or increases in interest rates, may also negatively impact &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;the liquidity of the Fund&#x2019;s investments when it needs to dispose of them. If the Fund is forced to sell its investments at an unfavorable time &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;and/or under adverse conditions in order to meet redemption requests, such sales could negatively affect the Fund. Securities acquired in a &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;private placement, such as Rule 144A securities, are generally subject to&#160;significant liquidity risk because they are subject to strict restrictions &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;on resale and there may be no liquid secondary market or ready purchaser for such securities. Liquidity issues may also make it difficult to &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;value the Fund&#x2019;s investments.&lt;/div&gt;&lt;/div&gt; &lt;div style="/* background-color:#FFFFFF; */padding-left:2pt;padding-top:5;padding-bottom:0;align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;text-align:left;"&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="font-weight:bold;display:inline;"&gt;Management Risk&lt;/div&gt;&lt;/div&gt;&lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt; is the risk that Loomis Sayles&#x2019; investment techniques will be unsuccessful and cause the Fund to incur &lt;div style="letter-spacing: 0px; top: 0px;;display:inline;"&gt;losses&lt;/div&gt;.&lt;/div&gt;&lt;/div&gt; &lt;div style="/* background-color:#FFFFFF; */padding-left:2pt;padding-top:5;padding-bottom:0;align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;text-align:left;"&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="letter-spacing: 0px; top: 0px;;display:inline;"&gt;&lt;div style="font-weight:bold;display:inline;"&gt;Market/Issuer Risk&lt;/div&gt;&lt;/div&gt;&lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt; is the risk that the market value of the Fund&#x2019;s investments will move up and down, sometimes rapidly and &lt;/div&gt;&lt;/div&gt; &lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;unpredictably, based upon overall market and economic conditions, as well as a number of reasons that directly relate to the issuers of the &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;Fund&#x2019;s investments, such as management performance, financial condition and demand for the issuers&#x2019; goods and services.&lt;/div&gt;</rr:RiskNarrativeTextBlock>
    <rr:RiskLoseMoney contextRef="P02_01_2021To02_01_2021_S000006639MemberdeiLegalEntityAxis">You may lose money by investing in the Fund</rr:RiskLoseMoney>
    <rr:BarChartAndPerformanceTableHeading contextRef="P02_01_2021To02_01_2021_S000006639MemberdeiLegalEntityAxis">Risk/Return Bar Chart and Table</rr:BarChartAndPerformanceTableHeading>
    <rr:PerformanceNarrativeTextBlock contextRef="P02_01_2021To02_01_2021_S000006639MemberdeiLegalEntityAxis">&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;The following bar chart and table give an indication of the risks of investing in the Fund by showing changes in the Fund&#x2019;s performance from year to year and by showing how the Fund&#x2019;s average annual returns for the one-year, five-year and ten-year periods compare to those of a broad measure of market performance. &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"/&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"/&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"/&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt; The Fund&#x2019;s past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future.&lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt; Updated performance information is available online at&#160;www.loomissayles.com and/or by &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px;;display:inline;"&gt;calling the Fund toll-free at 800-633-3330.&lt;/div&gt;</rr:PerformanceNarrativeTextBlock>
    <rr:PerformanceInformationIllustratesVariabilityOfReturns contextRef="P02_01_2021To02_01_2021_S000006639MemberdeiLegalEntityAxis">The following bar chart and table give an indication of the risks of investing in the Fund by showing changes in the Fund&#x2019;s performance from year to year and by showing how the Fund&#x2019;s average annual returns for the one-year, five-year and ten-year periods compare to those of a broad measure of market performance.</rr:PerformanceInformationIllustratesVariabilityOfReturns>
    <rr:PerformancePastDoesNotIndicateFuture contextRef="P02_01_2021To02_01_2021_S000006639MemberdeiLegalEntityAxis">The Fund&#x2019;s past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future.</rr:PerformancePastDoesNotIndicateFuture>
    <rr:PerformanceAvailabilityWebSiteAddress contextRef="P02_01_2021To02_01_2021_S000006639MemberdeiLegalEntityAxis">www.loomissayles.com</rr:PerformanceAvailabilityWebSiteAddress>
    <rr:PerformanceAvailabilityPhone contextRef="P02_01_2021To02_01_2021_S000006639MemberdeiLegalEntityAxis">800-633-3330</rr:PerformanceAvailabilityPhone>
    <rr:BarChartHeading contextRef="P02_01_2021To02_01_2021_S000006639MemberdeiLegalEntityAxis">Total Returns for Institutional Class Shares</rr:BarChartHeading>
    <rr:BarChartClosingTextBlock contextRef="P02_01_2021To02_01_2021_S000006639MemberdeiLegalEntityAxis">&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px; white-space: nowrap;;display:inline;"&gt;Highest Quarterly Return:&lt;/div&gt;&lt;br/&gt; &lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px; white-space: nowrap;;display:inline;"&gt;&lt;span style="-sec-ix-hidden:hidden3215267"&gt;Second Quarter 2020&lt;/span&gt;, &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px; white-space: nowrap;;display:inline;"&gt;3.83%&lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px; white-space: nowrap;;display:inline;"/&gt;&lt;br/&gt; &lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 8.02pt; letter-spacing: 0px; top: 0px; white-space: nowrap;;display:inline;"&gt;&#160;&lt;/div&gt;&lt;br/&gt; &lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px; white-space: nowrap;;display:inline;"&gt;Lowest Quarterly Return:&lt;/div&gt;&lt;br/&gt; &lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px; white-space: nowrap;;display:inline;"&gt;&lt;span style="-sec-ix-hidden:hidden3215268"&gt;Second Quarter 2013&lt;/span&gt;, &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px; white-space: nowrap;;display:inline;"&gt;-1.70%&lt;/div&gt;</rr:BarChartClosingTextBlock>
    <rr:HighestQuarterlyReturnLabel contextRef="P02_01_2021To02_01_2021_C000018125MemberrrProspectusShareClassAxis_S000006639MemberdeiLegalEntityAxis">Highest Quarterly Return:</rr:HighestQuarterlyReturnLabel>
    <rr:BarChartHighestQuarterlyReturn
      contextRef="P02_01_2021To02_01_2021_C000018125MemberrrProspectusShareClassAxis_S000006639MemberdeiLegalEntityAxis"
      decimals="INF"
      unitRef="Unit_pure">0.0383</rr:BarChartHighestQuarterlyReturn>
    <rr:LowestQuarterlyReturnLabel contextRef="P02_01_2021To02_01_2021_C000018125MemberrrProspectusShareClassAxis_S000006639MemberdeiLegalEntityAxis">Lowest Quarterly Return:</rr:LowestQuarterlyReturnLabel>
    <rr:BarChartLowestQuarterlyReturn
      contextRef="P02_01_2021To02_01_2021_C000018125MemberrrProspectusShareClassAxis_S000006639MemberdeiLegalEntityAxis"
      decimals="INF"
      unitRef="Unit_pure">-0.0170</rr:BarChartLowestQuarterlyReturn>
    <rr:PerformanceTableHeading contextRef="P02_01_2021To02_01_2021_S000006639MemberdeiLegalEntityAxis">Average Annual Total Returns &#160;(for the periods ended December 31, 2020) </rr:PerformanceTableHeading>
    <rr:AverageAnnualReturnYear01
      contextRef="P02_01_2021To02_01_2021_C000018125MemberrrProspectusShareClassAxis_S000006639MemberdeiLegalEntityAxis"
      decimals="INF"
      unitRef="Unit_pure">0.0467</rr:AverageAnnualReturnYear01>
    <rr:AverageAnnualReturnYear05
      contextRef="P02_01_2021To02_01_2021_C000018125MemberrrProspectusShareClassAxis_S000006639MemberdeiLegalEntityAxis"
      decimals="INF"
      unitRef="Unit_pure">0.0408</rr:AverageAnnualReturnYear05>
    <rr:AverageAnnualReturnYear10
      contextRef="P02_01_2021To02_01_2021_C000018125MemberrrProspectusShareClassAxis_S000006639MemberdeiLegalEntityAxis"
      decimals="INF"
      unitRef="Unit_pure">0.0439</rr:AverageAnnualReturnYear10>
    <rr:AverageAnnualReturnYear01
      contextRef="P02_01_2021To02_01_2021_AfterTaxesOnDistributionsMemberrrPerformanceMeasureAxis_C000018125MemberrrProspectusShareClassAxis_S000006639MemberdeiLegalEntityAxis"
      decimals="INF"
      unitRef="Unit_pure">0.0218</rr:AverageAnnualReturnYear01>
    <rr:AverageAnnualReturnYear05
      contextRef="P02_01_2021To02_01_2021_AfterTaxesOnDistributionsMemberrrPerformanceMeasureAxis_C000018125MemberrrProspectusShareClassAxis_S000006639MemberdeiLegalEntityAxis"
      decimals="INF"
      unitRef="Unit_pure">0.0174</rr:AverageAnnualReturnYear05>
    <rr:AverageAnnualReturnYear10
      contextRef="P02_01_2021To02_01_2021_AfterTaxesOnDistributionsMemberrrPerformanceMeasureAxis_C000018125MemberrrProspectusShareClassAxis_S000006639MemberdeiLegalEntityAxis"
      decimals="INF"
      unitRef="Unit_pure">0.0210</rr:AverageAnnualReturnYear10>
    <rr:AverageAnnualReturnYear01
      contextRef="P02_01_2021To02_01_2021_AfterTaxesOnDistributionsAndSalesMemberrrPerformanceMeasureAxis_C000018125MemberrrProspectusShareClassAxis_S000006639MemberdeiLegalEntityAxis"
      decimals="INF"
      unitRef="Unit_pure">0.0273</rr:AverageAnnualReturnYear01>
    <rr:AverageAnnualReturnYear05
      contextRef="P02_01_2021To02_01_2021_AfterTaxesOnDistributionsAndSalesMemberrrPerformanceMeasureAxis_C000018125MemberrrProspectusShareClassAxis_S000006639MemberdeiLegalEntityAxis"
      decimals="INF"
      unitRef="Unit_pure">0.0207</rr:AverageAnnualReturnYear05>
    <rr:AverageAnnualReturnYear10
      contextRef="P02_01_2021To02_01_2021_AfterTaxesOnDistributionsAndSalesMemberrrPerformanceMeasureAxis_C000018125MemberrrProspectusShareClassAxis_S000006639MemberdeiLegalEntityAxis"
      decimals="INF"
      unitRef="Unit_pure">0.0238</rr:AverageAnnualReturnYear10>
    <rr:AverageAnnualReturnYear01
      contextRef="P02_01_2021To02_01_2021_BloombergBarclaysUsSecuritizedBondIndexMemberrrPerformanceMeasureAxis_S000006639MemberdeiLegalEntityAxis"
      decimals="INF"
      unitRef="Unit_pure">0.0418</rr:AverageAnnualReturnYear01>
    <rr:AverageAnnualReturnYear05
      contextRef="P02_01_2021To02_01_2021_BloombergBarclaysUsSecuritizedBondIndexMemberrrPerformanceMeasureAxis_S000006639MemberdeiLegalEntityAxis"
      decimals="INF"
      unitRef="Unit_pure">0.0316</rr:AverageAnnualReturnYear05>
    <rr:AverageAnnualReturnYear10
      contextRef="P02_01_2021To02_01_2021_BloombergBarclaysUsSecuritizedBondIndexMemberrrPerformanceMeasureAxis_S000006639MemberdeiLegalEntityAxis"
      decimals="INF"
      unitRef="Unit_pure">0.0309</rr:AverageAnnualReturnYear10>
    <rr:PerformanceTableNarrativeTextBlock contextRef="P02_01_2021To02_01_2021_S000006639MemberdeiLegalEntityAxis">After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the&#160;impact of state and local taxes. &lt;div style="color: rgb(0, 0, 0); font-family: Arial, Helvetica, sans-serif; font-size: 14.0267px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: left; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255); text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial; float: none; display: inline !important; top: 0px;;display:inline;"&gt;Actual after-tax returns depend on an investor&#x2019;s tax situation and may differ from those shown.&#160;After-tax returns shown are&lt;div style="letter-spacing: 0px; top: 0px;;display:inline;"&gt;&#160;&lt;/div&gt;&lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px; text-indent: 0px;;display:inline;"&gt;not relevant to investors who hold their shares through tax-advantaged arrangements, such as 401(k)&#160;plans, qualified plans, education savings accounts, such as 529 plans, or individual retirement accounts. &lt;/div&gt;&lt;div style="font-family: Arial, Helvetica, sans-serif; font-size: 10.52pt; letter-spacing: 0px; top: 0px; text-indent: 0px;;display:inline;"&gt;Index performance&#160;reflects no deduction for fees, expenses or taxes.&lt;/div&gt;</rr:PerformanceTableNarrativeTextBlock>
    <rr:PerformanceTableUsesHighestFederalRate contextRef="P02_01_2021To02_01_2021_S000006639MemberdeiLegalEntityAxis">After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the&#160;impact of state and local taxes.</rr:PerformanceTableUsesHighestFederalRate>
    <rr:PerformanceTableNotRelevantToTaxDeferred contextRef="P02_01_2021To02_01_2021_S000006639MemberdeiLegalEntityAxis">Actual after-tax returns depend on an investor&#x2019;s tax situation and may differ from those shown.&#160;After-tax returns shown are&#160;not relevant to investors who hold their shares through tax-advantaged arrangements, such as 401(k)&#160;plans, qualified plans, education savings accounts, such as 529 plans, or individual retirement accounts. </rr:PerformanceTableNotRelevantToTaxDeferred>
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        <link:footnote id="FN_26626" xlink:label="FN_26626" xlink:role="http://www.xbrl.org/2003/role/footnote" xlink:type="resource" xml:lang="en-US">The amounts shown in the table are 0.00% to reflect the fact that the Fund does not pay any advisory, administration or distribution and service fees, and that Loomis, Sayles &amp; Company, L.P. (&#x201c;Loomis Sayles&#x201d; or the &#x201c;Adviser&#x201d;) has agreed to pay certain expenses of the Fund. You should be aware, however, that shares of the Fund are available only to institutional investment advisory clients of Loomis Sayles and Natixis Advisors, L.P. (&#x201c;Natixis Advisors&#x201d;) and to participants in certain approved &#x201c;wrap fee&#x201d; programs sponsored by broker-dealers and investment advisers that may be affiliated or unaffiliated with the Fund, Loomis Sayles or Natixis Advisors. The institutional investment advisory clients of Loomis Sayles and Natixis Advisors pay Loomis Sayles or Natixis Advisors a fee for their investment advisory services, while participants in &#x201c;wrap fee&#x201d; programs pay a &#x201c;wrap&#x201d; fee to the program&#x2019;s sponsor. The &#x201c;wrap fee&#x201d; program sponsors in turn pay fees to Natixis Advisors. Participants in &#x201c;wrap fee&#x201d; programs should carefully read the wrap fee brochure provided to them by their program&#x2019;s sponsor. The brochure is required to include information about the fees charged by the &#x201c;wrap fee&#x201d; program sponsor and the fees paid by such sponsor to Natixis Advisors. Investors pay no additional fees or expenses to purchase shares of the Fund. Investors will, however, indirectly pay a proportionate share of those costs, such as brokerage commissions, taxes and extraordinary expenses that are borne by the Fund through a reduction in their net asset value. See the section &#x201c;Management&#x201d; in the Statutory Prospectus.</link:footnote>
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