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            <endDate>2026-04-30</endDate>
        </period>
    </context>
    <unit id="usd">
        <measure>iso4217:USD</measure>
    </unit>
    <unit id="pure">
        <measure>pure</measure>
    </unit>
    <dei:EntityInvCompanyType contextRef="Context_20260430_20260430" id="ixv-28440">N-1A</dei:EntityInvCompanyType>
    <dei:EntityRegistrantName contextRef="Context_20260430_20260430" id="ixv-28441">MFS&#xae;  SERIES TRUST XII</dei:EntityRegistrantName>
    <dei:DocumentEffectiveDate contextRef="Context_20260430_20260430" id="ixv-28443">2026-05-19</dei:DocumentEffectiveDate>
    <oef:ProspectusDate contextRef="Context_20260430_20260430" id="ixv-28444">2026-05-27</oef:ProspectusDate>
    <oef:RiskReturnHeading
      contextRef="Context_20260430_20260430_S000104920Member_S000104920Summary1Member"
      id="ixv-28445">MFS&#xae; 
Lifetime&#xae; 2070 Fund  Summary 
of Key Information</oef:RiskReturnHeading>
    <dei:TradingSymbol
      contextRef="Context_20260430_20260430_C000275574Member_S000104920Member_S000104920Summary1Member"
      id="ixv-28446">LFTQX</dei:TradingSymbol>
    <dei:TradingSymbol
      contextRef="Context_20260430_20260430_C000275577Member_S000104920Member_S000104920Summary1Member"
      id="ixv-28447">MLTPX</dei:TradingSymbol>
    <dei:TradingSymbol
      contextRef="Context_20260430_20260430_C000275576Member_S000104920Member_S000104920Summary1Member"
      id="ixv-28448">MLTQX</dei:TradingSymbol>
    <dei:TradingSymbol
      contextRef="Context_20260430_20260430_C000275575Member_S000104920Member_S000104920Summary1Member"
      id="ixv-28449">MLTRX</dei:TradingSymbol>
    <dei:TradingSymbol
      contextRef="Context_20260430_20260430_C000275578Member_S000104920Member_S000104920Summary1Member"
      id="ixv-28450">MLTTX</dei:TradingSymbol>
    <dei:TradingSymbol
      contextRef="Context_20260430_20260430_C000275573Member_S000104920Member_S000104920Summary1Member"
      id="ixv-28451">LFTVX</dei:TradingSymbol>
    <dei:TradingSymbol
      contextRef="Context_20260430_20260430_C000275572Member_S000104920Member_S000104920Summary1Member"
      id="ixv-28452">LFTWX</dei:TradingSymbol>
    <dei:TradingSymbol
      contextRef="Context_20260430_20260430_C000275571Member_S000104920Member_S000104920Summary1Member"
      id="ixv-28453">LFTZX</dei:TradingSymbol>
    <oef:ObjectiveHeading
      contextRef="Context_20260430_20260430_S000104920Member_S000104920Summary1Member"
      id="ixv-28455">Investment Objective</oef:ObjectiveHeading>
    <oef:ObjectivePrimaryTextBlock
      contextRef="Context_20260430_20260430_S000104920Member_S000104920Summary1Member"
      id="ixv-260">&lt;p style="margin-top:revert; margin-bottom:revert; font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;"&gt;The fund&#x2019;s 
investment objective is to seek a high level of total return consistent with its asset allocation until 
the approximate retirement year in the fund's name; thereafter, the fund will seek total return through 
a combination of current income and capital appreciation. The asset allocation of the fund will change 
over time. &lt;/p&gt;</oef:ObjectivePrimaryTextBlock>
    <oef:ExpenseHeading
      contextRef="Context_20260430_20260430_S000104920Member_S000104920Summary1Member"
      id="ixv-28456">Fees and Expenses  </oef:ExpenseHeading>
    <oef:ExpenseNarrativeTextBlock
      contextRef="Context_20260430_20260430_S000104920Member_S000104920Summary1Member"
      id="ixv-263">&lt;p style="margin-top:revert; margin-bottom:revert;font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"&gt;This table describes the 
fees and expenses that you may pay when you buy, hold, and sell shares of the fund. &lt;/span&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;"&gt;Investors 
may also pay commissions or other fees to their financial intermediaries when they buy, hold, and sell 
shares of the fund, which are not reflected below.&lt;/span&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"&gt;   The annual fund operating 
expenses are based on estimated "Other Expenses" and "Acquired (Underlying) Fund Fees and Expenses" for 
the current fiscal year expressed as a percentage of each class' estimated average net assets during 
the period.&lt;/span&gt;&lt;/p&gt;&lt;p style="margin-top:revert; margin-bottom:revert;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;"&gt;You may qualify for sales charge reductions 
if, with respect to Class A shares, you and certain members of your family invest, or agree to invest 
in the future, at least $50,000 in MFS funds. More information about these and other waivers and reductions 
is available from your financial intermediary and in &#x201c;Sales Charges and Waivers and Reductions&#x201d; on 
page 15 and &#x201c;Appendix A &#x2013; Waivers and Reductions of Sales Charges&#x201d; on page A-1 of the fund&#x2019;s 
prospectus. &lt;/p&gt;</oef:ExpenseNarrativeTextBlock>
    <oef:ExpenseBreakpointDiscounts
      contextRef="Context_20260430_20260430_S000104920Member_S000104920Summary1Member"
      id="ixv-28457">You may qualify for sales charge reductions 
if, with respect to Class A shares, you and certain members of your family invest, or agree to invest 
in the future, at least $50,000 in MFS funds.</oef:ExpenseBreakpointDiscounts>
    <oef:ExpenseBreakpointMinimumInvestmentRequiredAmount
      contextRef="Context_20260430_20260430_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28458"
      unitRef="usd">50000</oef:ExpenseBreakpointMinimumInvestmentRequiredAmount>
    <oef:ShareholderFeesCaption
      contextRef="Context_20260430_20260430_S000104920Member_S000104920Summary1Member"
      id="ixv-28459">Shareholder 
Fees (fees paid directly from your investment):</oef:ShareholderFeesCaption>
    <oef:MaximumSalesChargeImposedOnPurchasesOverOfferingPrice
      contextRef="Context_20260430_20260430_C000275574Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28461"
      unitRef="pure">0.0575</oef:MaximumSalesChargeImposedOnPurchasesOverOfferingPrice>
    <oef:MaximumSalesChargeImposedOnPurchasesOverOfferingPrice
      contextRef="Context_20260430_20260430_C000275577Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28462"
      unitRef="pure">0</oef:MaximumSalesChargeImposedOnPurchasesOverOfferingPrice>
    <oef:MaximumSalesChargeImposedOnPurchasesOverOfferingPrice
      contextRef="Context_20260430_20260430_C000275576Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28463"
      unitRef="pure">0</oef:MaximumSalesChargeImposedOnPurchasesOverOfferingPrice>
    <oef:MaximumSalesChargeImposedOnPurchasesOverOfferingPrice
      contextRef="Context_20260430_20260430_C000275575Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28464"
      unitRef="pure">0</oef:MaximumSalesChargeImposedOnPurchasesOverOfferingPrice>
    <oef:MaximumSalesChargeImposedOnPurchasesOverOfferingPrice
      contextRef="Context_20260430_20260430_C000275578Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28465"
      unitRef="pure">0</oef:MaximumSalesChargeImposedOnPurchasesOverOfferingPrice>
    <oef:MaximumSalesChargeImposedOnPurchasesOverOfferingPrice
      contextRef="Context_20260430_20260430_C000275573Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28466"
      unitRef="pure">0</oef:MaximumSalesChargeImposedOnPurchasesOverOfferingPrice>
    <oef:MaximumSalesChargeImposedOnPurchasesOverOfferingPrice
      contextRef="Context_20260430_20260430_C000275572Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28467"
      unitRef="pure">0</oef:MaximumSalesChargeImposedOnPurchasesOverOfferingPrice>
    <oef:MaximumSalesChargeImposedOnPurchasesOverOfferingPrice
      contextRef="Context_20260430_20260430_C000275571Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28468"
      unitRef="pure">0</oef:MaximumSalesChargeImposedOnPurchasesOverOfferingPrice>
    <oef:MaximumDeferredSalesChargeOverOfferingPrice
      contextRef="Context_20260430_20260430_C000275574Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="_37_"
      unitRef="pure">0.0100</oef:MaximumDeferredSalesChargeOverOfferingPrice>
    <oef:MaximumDeferredSalesChargeOverOfferingPrice
      contextRef="Context_20260430_20260430_C000275577Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28470"
      unitRef="pure">0.0100</oef:MaximumDeferredSalesChargeOverOfferingPrice>
    <oef:MaximumDeferredSalesChargeOverOfferingPrice
      contextRef="Context_20260430_20260430_C000275576Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28471"
      unitRef="pure">0</oef:MaximumDeferredSalesChargeOverOfferingPrice>
    <oef:MaximumDeferredSalesChargeOverOfferingPrice
      contextRef="Context_20260430_20260430_C000275575Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28472"
      unitRef="pure">0</oef:MaximumDeferredSalesChargeOverOfferingPrice>
    <oef:MaximumDeferredSalesChargeOverOfferingPrice
      contextRef="Context_20260430_20260430_C000275578Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28473"
      unitRef="pure">0</oef:MaximumDeferredSalesChargeOverOfferingPrice>
    <oef:MaximumDeferredSalesChargeOverOfferingPrice
      contextRef="Context_20260430_20260430_C000275573Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28474"
      unitRef="pure">0</oef:MaximumDeferredSalesChargeOverOfferingPrice>
    <oef:MaximumDeferredSalesChargeOverOfferingPrice
      contextRef="Context_20260430_20260430_C000275572Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28475"
      unitRef="pure">0</oef:MaximumDeferredSalesChargeOverOfferingPrice>
    <oef:MaximumDeferredSalesChargeOverOfferingPrice
      contextRef="Context_20260430_20260430_C000275571Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28476"
      unitRef="pure">0</oef:MaximumDeferredSalesChargeOverOfferingPrice>
    <oef:OperatingExpensesCaption
      contextRef="Context_20260430_20260430_S000104920Member_S000104920Summary1Member"
      id="ixv-28477">Annual Fund Operating Expenses (expenses that you pay each year as a percentage 
of the value of your investment):</oef:OperatingExpensesCaption>
    <oef:ManagementFeesOverAssets
      contextRef="Context_20260430_20260430_C000275574Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28479"
      unitRef="pure">0.0000</oef:ManagementFeesOverAssets>
    <oef:ManagementFeesOverAssets
      contextRef="Context_20260430_20260430_C000275577Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28480"
      unitRef="pure">0.0000</oef:ManagementFeesOverAssets>
    <oef:ManagementFeesOverAssets
      contextRef="Context_20260430_20260430_C000275576Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28481"
      unitRef="pure">0.0000</oef:ManagementFeesOverAssets>
    <oef:ManagementFeesOverAssets
      contextRef="Context_20260430_20260430_C000275575Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28482"
      unitRef="pure">0.0000</oef:ManagementFeesOverAssets>
    <oef:ManagementFeesOverAssets
      contextRef="Context_20260430_20260430_C000275578Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28483"
      unitRef="pure">0.0000</oef:ManagementFeesOverAssets>
    <oef:ManagementFeesOverAssets
      contextRef="Context_20260430_20260430_C000275573Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28484"
      unitRef="pure">0.0000</oef:ManagementFeesOverAssets>
    <oef:ManagementFeesOverAssets
      contextRef="Context_20260430_20260430_C000275572Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28485"
      unitRef="pure">0.0000</oef:ManagementFeesOverAssets>
    <oef:ManagementFeesOverAssets
      contextRef="Context_20260430_20260430_C000275571Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28486"
      unitRef="pure">0.0000</oef:ManagementFeesOverAssets>
    <oef:DistributionAndService12b1FeesOverAssets
      contextRef="Context_20260430_20260430_C000275574Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28487"
      unitRef="pure">0.0025</oef:DistributionAndService12b1FeesOverAssets>
    <oef:DistributionAndService12b1FeesOverAssets
      contextRef="Context_20260430_20260430_C000275577Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28488"
      unitRef="pure">0.0100</oef:DistributionAndService12b1FeesOverAssets>
    <oef:DistributionAndService12b1FeesOverAssets
      contextRef="Context_20260430_20260430_C000275576Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28489"
      unitRef="pure">0</oef:DistributionAndService12b1FeesOverAssets>
    <oef:DistributionAndService12b1FeesOverAssets
      contextRef="Context_20260430_20260430_C000275575Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28490"
      unitRef="pure">0.0100</oef:DistributionAndService12b1FeesOverAssets>
    <oef:DistributionAndService12b1FeesOverAssets
      contextRef="Context_20260430_20260430_C000275578Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28491"
      unitRef="pure">0.0050</oef:DistributionAndService12b1FeesOverAssets>
    <oef:DistributionAndService12b1FeesOverAssets
      contextRef="Context_20260430_20260430_C000275573Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28492"
      unitRef="pure">0.0025</oef:DistributionAndService12b1FeesOverAssets>
    <oef:DistributionAndService12b1FeesOverAssets
      contextRef="Context_20260430_20260430_C000275572Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28493"
      unitRef="pure">0</oef:DistributionAndService12b1FeesOverAssets>
    <oef:DistributionAndService12b1FeesOverAssets
      contextRef="Context_20260430_20260430_C000275571Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28494"
      unitRef="pure">0</oef:DistributionAndService12b1FeesOverAssets>
    <oef:OtherExpensesOverAssets
      contextRef="Context_20260430_20260430_C000275574Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28495"
      unitRef="pure">0.0447</oef:OtherExpensesOverAssets>
    <oef:OtherExpensesOverAssets
      contextRef="Context_20260430_20260430_C000275577Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28496"
      unitRef="pure">0.0447</oef:OtherExpensesOverAssets>
    <oef:OtherExpensesOverAssets
      contextRef="Context_20260430_20260430_C000275576Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28497"
      unitRef="pure">0.0447</oef:OtherExpensesOverAssets>
    <oef:OtherExpensesOverAssets
      contextRef="Context_20260430_20260430_C000275575Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28498"
      unitRef="pure">0.0447</oef:OtherExpensesOverAssets>
    <oef:OtherExpensesOverAssets
      contextRef="Context_20260430_20260430_C000275578Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28499"
      unitRef="pure">0.0447</oef:OtherExpensesOverAssets>
    <oef:OtherExpensesOverAssets
      contextRef="Context_20260430_20260430_C000275573Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28500"
      unitRef="pure">0.0447</oef:OtherExpensesOverAssets>
    <oef:OtherExpensesOverAssets
      contextRef="Context_20260430_20260430_C000275572Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28501"
      unitRef="pure">0.0447</oef:OtherExpensesOverAssets>
    <oef:OtherExpensesOverAssets
      contextRef="Context_20260430_20260430_C000275571Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28502"
      unitRef="pure">0.0433</oef:OtherExpensesOverAssets>
    <oef:AcquiredFundFeesAndExpensesOverAssets
      contextRef="Context_20260430_20260430_C000275574Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28503"
      unitRef="pure">0.0055</oef:AcquiredFundFeesAndExpensesOverAssets>
    <oef:AcquiredFundFeesAndExpensesOverAssets
      contextRef="Context_20260430_20260430_C000275577Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28504"
      unitRef="pure">0.0055</oef:AcquiredFundFeesAndExpensesOverAssets>
    <oef:AcquiredFundFeesAndExpensesOverAssets
      contextRef="Context_20260430_20260430_C000275576Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28505"
      unitRef="pure">0.0055</oef:AcquiredFundFeesAndExpensesOverAssets>
    <oef:AcquiredFundFeesAndExpensesOverAssets
      contextRef="Context_20260430_20260430_C000275575Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28506"
      unitRef="pure">0.0055</oef:AcquiredFundFeesAndExpensesOverAssets>
    <oef:AcquiredFundFeesAndExpensesOverAssets
      contextRef="Context_20260430_20260430_C000275578Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28507"
      unitRef="pure">0.0055</oef:AcquiredFundFeesAndExpensesOverAssets>
    <oef:AcquiredFundFeesAndExpensesOverAssets
      contextRef="Context_20260430_20260430_C000275573Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28508"
      unitRef="pure">0.0055</oef:AcquiredFundFeesAndExpensesOverAssets>
    <oef:AcquiredFundFeesAndExpensesOverAssets
      contextRef="Context_20260430_20260430_C000275572Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28509"
      unitRef="pure">0.0055</oef:AcquiredFundFeesAndExpensesOverAssets>
    <oef:AcquiredFundFeesAndExpensesOverAssets
      contextRef="Context_20260430_20260430_C000275571Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28510"
      unitRef="pure">0.0055</oef:AcquiredFundFeesAndExpensesOverAssets>
    <oef:ExpensesOverAssets
      contextRef="Context_20260430_20260430_C000275574Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28511"
      unitRef="pure">0.0527</oef:ExpensesOverAssets>
    <oef:ExpensesOverAssets
      contextRef="Context_20260430_20260430_C000275577Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28512"
      unitRef="pure">0.0602</oef:ExpensesOverAssets>
    <oef:ExpensesOverAssets
      contextRef="Context_20260430_20260430_C000275576Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28513"
      unitRef="pure">0.0502</oef:ExpensesOverAssets>
    <oef:ExpensesOverAssets
      contextRef="Context_20260430_20260430_C000275575Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28514"
      unitRef="pure">0.0602</oef:ExpensesOverAssets>
    <oef:ExpensesOverAssets
      contextRef="Context_20260430_20260430_C000275578Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28515"
      unitRef="pure">0.0552</oef:ExpensesOverAssets>
    <oef:ExpensesOverAssets
      contextRef="Context_20260430_20260430_C000275573Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28516"
      unitRef="pure">0.0527</oef:ExpensesOverAssets>
    <oef:ExpensesOverAssets
      contextRef="Context_20260430_20260430_C000275572Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28517"
      unitRef="pure">0.0502</oef:ExpensesOverAssets>
    <oef:ExpensesOverAssets
      contextRef="Context_20260430_20260430_C000275571Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28518"
      unitRef="pure">0.0488</oef:ExpensesOverAssets>
    <oef:FeeWaiverOrReimbursementOverAssets
      contextRef="Context_20260430_20260430_C000275574Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="_85_"
      unitRef="pure">-0.0447</oef:FeeWaiverOrReimbursementOverAssets>
    <oef:FeeWaiverOrReimbursementOverAssets
      contextRef="Context_20260430_20260430_C000275577Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="_86_"
      unitRef="pure">-0.0447</oef:FeeWaiverOrReimbursementOverAssets>
    <oef:FeeWaiverOrReimbursementOverAssets
      contextRef="Context_20260430_20260430_C000275576Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="_87_"
      unitRef="pure">-0.0447</oef:FeeWaiverOrReimbursementOverAssets>
    <oef:FeeWaiverOrReimbursementOverAssets
      contextRef="Context_20260430_20260430_C000275575Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="_88_"
      unitRef="pure">-0.0447</oef:FeeWaiverOrReimbursementOverAssets>
    <oef:FeeWaiverOrReimbursementOverAssets
      contextRef="Context_20260430_20260430_C000275578Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="_89_"
      unitRef="pure">-0.0447</oef:FeeWaiverOrReimbursementOverAssets>
    <oef:FeeWaiverOrReimbursementOverAssets
      contextRef="Context_20260430_20260430_C000275573Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="_90_"
      unitRef="pure">-0.0447</oef:FeeWaiverOrReimbursementOverAssets>
    <oef:FeeWaiverOrReimbursementOverAssets
      contextRef="Context_20260430_20260430_C000275572Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="_91_"
      unitRef="pure">-0.0447</oef:FeeWaiverOrReimbursementOverAssets>
    <oef:FeeWaiverOrReimbursementOverAssets
      contextRef="Context_20260430_20260430_C000275571Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="_92_"
      unitRef="pure">-0.0447</oef:FeeWaiverOrReimbursementOverAssets>
    <oef:NetExpensesOverAssets
      contextRef="Context_20260430_20260430_C000275574Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28527"
      unitRef="pure">0.0080</oef:NetExpensesOverAssets>
    <oef:NetExpensesOverAssets
      contextRef="Context_20260430_20260430_C000275577Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28528"
      unitRef="pure">0.0155</oef:NetExpensesOverAssets>
    <oef:NetExpensesOverAssets
      contextRef="Context_20260430_20260430_C000275576Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28529"
      unitRef="pure">0.0055</oef:NetExpensesOverAssets>
    <oef:NetExpensesOverAssets
      contextRef="Context_20260430_20260430_C000275575Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28530"
      unitRef="pure">0.0155</oef:NetExpensesOverAssets>
    <oef:NetExpensesOverAssets
      contextRef="Context_20260430_20260430_C000275578Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28531"
      unitRef="pure">0.0105</oef:NetExpensesOverAssets>
    <oef:NetExpensesOverAssets
      contextRef="Context_20260430_20260430_C000275573Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28532"
      unitRef="pure">0.0080</oef:NetExpensesOverAssets>
    <oef:NetExpensesOverAssets
      contextRef="Context_20260430_20260430_C000275572Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28533"
      unitRef="pure">0.0055</oef:NetExpensesOverAssets>
    <oef:NetExpensesOverAssets
      contextRef="Context_20260430_20260430_C000275571Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28534"
      unitRef="pure">0.0041</oef:NetExpensesOverAssets>
    <oef:ExpenseExampleHeading
      contextRef="Context_20260430_20260430_S000104920Member_S000104920Summary1Member"
      id="ixv-28535">Example 
</oef:ExpenseExampleHeading>
    <oef:ExpenseExampleNarrativeTextBlock
      contextRef="Context_20260430_20260430_S000104920Member_S000104920Summary1Member"
      id="ixv-794">&lt;p style="margin-top:revert; margin-bottom:revert; font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;"&gt;This example is intended to help you compare the cost of investing 
in the fund with the cost of investing in other mutual funds. &lt;/p&gt;&lt;p style="margin-top:revert; margin-bottom:revert; font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;"&gt;The example 
assumes that: you invest $10,000 in the fund for the time periods indicated and you redeem your shares 
at the end of the time periods (unless otherwise indicated); your investment has a 5% return each year; 
and the fund&#x2019;s operating expenses remain the same. &lt;/p&gt;</oef:ExpenseExampleNarrativeTextBlock>
    <oef:ExpenseExampleByYearCaption
      contextRef="Context_20260430_20260430_S000104920Member_S000104920Summary1Member"
      id="ixv-28536">Although 
your actual costs will likely be higher or lower, under these assumptions your costs would be:</oef:ExpenseExampleByYearCaption>
    <oef:ExpenseExampleYear01
      contextRef="Context_20260430_20260430_C000275574Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28537"
      unitRef="usd">652</oef:ExpenseExampleYear01>
    <oef:ExpenseExampleYear03
      contextRef="Context_20260430_20260430_C000275574Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28538"
      unitRef="usd">1577</oef:ExpenseExampleYear03>
    <oef:ExpenseExampleYear01
      contextRef="Context_20260430_20260430_C000275577Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28539"
      unitRef="usd">258</oef:ExpenseExampleYear01>
    <oef:ExpenseExampleYear03
      contextRef="Context_20260430_20260430_C000275577Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28540"
      unitRef="usd">1279</oef:ExpenseExampleYear03>
    <oef:ExpenseExampleNoRedemptionYear01
      contextRef="Context_20260430_20260430_C000275577Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28541"
      unitRef="usd">158</oef:ExpenseExampleNoRedemptionYear01>
    <oef:ExpenseExampleNoRedemptionYear03
      contextRef="Context_20260430_20260430_C000275577Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28542"
      unitRef="usd">1279</oef:ExpenseExampleNoRedemptionYear03>
    <oef:ExpenseExampleYear01
      contextRef="Context_20260430_20260430_C000275576Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28543"
      unitRef="usd">56</oef:ExpenseExampleYear01>
    <oef:ExpenseExampleYear03
      contextRef="Context_20260430_20260430_C000275576Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28544"
      unitRef="usd">990</oef:ExpenseExampleYear03>
    <oef:ExpenseExampleYear01
      contextRef="Context_20260430_20260430_C000275575Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28545"
      unitRef="usd">158</oef:ExpenseExampleYear01>
    <oef:ExpenseExampleYear03
      contextRef="Context_20260430_20260430_C000275575Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28546"
      unitRef="usd">1279</oef:ExpenseExampleYear03>
    <oef:ExpenseExampleYear01
      contextRef="Context_20260430_20260430_C000275578Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28547"
      unitRef="usd">107</oef:ExpenseExampleYear01>
    <oef:ExpenseExampleYear03
      contextRef="Context_20260430_20260430_C000275578Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28548"
      unitRef="usd">1136</oef:ExpenseExampleYear03>
    <oef:ExpenseExampleYear01
      contextRef="Context_20260430_20260430_C000275573Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28549"
      unitRef="usd">82</oef:ExpenseExampleYear01>
    <oef:ExpenseExampleYear03
      contextRef="Context_20260430_20260430_C000275573Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28550"
      unitRef="usd">1063</oef:ExpenseExampleYear03>
    <oef:ExpenseExampleYear01
      contextRef="Context_20260430_20260430_C000275572Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28551"
      unitRef="usd">56</oef:ExpenseExampleYear01>
    <oef:ExpenseExampleYear03
      contextRef="Context_20260430_20260430_C000275572Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28552"
      unitRef="usd">990</oef:ExpenseExampleYear03>
    <oef:ExpenseExampleYear01
      contextRef="Context_20260430_20260430_C000275571Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28553"
      unitRef="usd">42</oef:ExpenseExampleYear01>
    <oef:ExpenseExampleYear03
      contextRef="Context_20260430_20260430_C000275571Member_S000104920Member_S000104920Summary1Member"
      decimals="INF"
      id="ixv-28554"
      unitRef="usd">949</oef:ExpenseExampleYear03>
    <oef:PortfolioTurnoverHeading
      contextRef="Context_20260430_20260430_S000104920Member_S000104920Summary1Member"
      id="ixv-28555">Portfolio 
Turnover</oef:PortfolioTurnoverHeading>
    <oef:PortfolioTurnoverTextBlock
      contextRef="Context_20260430_20260430_S000104920Member_S000104920Summary1Member"
      id="ixv-989">&lt;p style="margin-top:revert; margin-bottom:revert; font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;"&gt;The fund pays transaction costs, such as commissions, when 
it buys and sells securities (or &#x201c;turns over&#x201d; its portfolio). A higher portfolio turnover rate may 
indicate higher transaction costs and may result in higher taxes when shares are held in a taxable account. 
These transaction costs, which are not reflected in &#x201c;Annual Fund Operating Expenses&#x201d; or in the &#x201c;Example,&#x201d; 
affect the fund&#x2019;s performance. The portfolio turnover rate for the fund is not available because the 
fund had not commenced operations as of the date of this prospectus.&lt;/p&gt;</oef:PortfolioTurnoverTextBlock>
    <oef:StrategyHeading
      contextRef="Context_20260430_20260430_S000104920Member_S000104920Summary1Member"
      id="ixv-28556">Principal Investment Strategies</oef:StrategyHeading>
    <oef:StrategyNarrativeTextBlock
      contextRef="Context_20260430_20260430_S000104920Member_S000104920Summary1Member"
      id="ixv-992">&lt;p style="margin-top:revert; margin-bottom:revert; font-size:10.0pt; font-family:Serif; font-style:normal; text-align:justify; color:#000000; font-weight:normal; text-decoration:none;"&gt;The fund is designed to provide diversification among different asset classes 
for investors with the approximate retirement year in the fund's name. MFS (Massachusetts Financial Services 
Company, the fund's investment adviser) invests substantially all of the fund's assets in other MFS mutual 
funds, referred to as underlying funds. &lt;/p&gt;&lt;p style="margin-top:revert; margin-bottom:revert; font-size:10.0pt; font-family:Serif; font-style:normal; text-align:justify; color:#000000; font-weight:normal; text-decoration:none;"&gt;MFS selects the asset class 
allocations based on a strategic asset allocation process that takes into account a variety of factors, 
including historical risk and performance, projected performance, and other factors. MFS&#x2019; analyses 
of projected performance are primarily based on quantitative models using various inputs such as valuation 
metrics, growth rates, profitability, yields, and inflation. MFS may also consider current market conditions, 
its qualitative assessment of the risk/return characteristics of asset classes, and other factors in 
determining these allocations.&lt;/p&gt;&lt;p style="margin-top:revert; margin-bottom:revert;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:justify; color:#000000; font-weight:normal; text-decoration:none;"&gt;MFS employs the strategic 
asset allocation process described above to determine the amount of the fund's assets invested in (1) 
underlying funds that invest primarily in equity securities (&#x201c;Equity Funds&#x201d;) and underlying funds 
that provide exposure to less traditional asset classes, currently real estate and commodities (&#x201c;Non-Traditional 
Funds&#x201d;) and (2) underlying funds that invest primarily in debt instruments (&#x201c;Bond Funds&#x201d;) and an 
underlying fund that invests in cash and/or cash equivalents (&#x201c;Money Market Fund&#x201d;).&lt;/p&gt;&lt;p style="margin-top:revert; margin-bottom:revert; font-size:10.0pt; font-family:Serif; font-style:normal; text-align:justify; color:#000000; font-weight:normal; text-decoration:none;"&gt;MFS selects the underlying funds within each asset class based on underlying fund 
classifications, historical risk, historical and projected performance of the represented asset classes, 
as well as other factors. &lt;/p&gt;&lt;p style="margin-top:revert; margin-bottom:revert;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:justify; color:#000000; font-weight:normal; text-decoration:none;"&gt;Within the Equity Fund 
allocation, MFS seeks to diversify by geography (by including domestic and international underlying funds, 
including emerging market underlying funds), in terms of market capitalization (by including large, mid, 
and small capitalization underlying funds) and by style (by including both growth and value underlying 
funds). A portion of the fund&#x2019;s assets is also allocated to Non-Traditional Funds (i.e., asset classes 
less correlated to the overall equity and debt markets), which MFS believes provides further diversification 
benefits. &lt;/p&gt;&lt;p style="margin-top:revert; margin-bottom:revert;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:justify; color:#000000; font-weight:normal; text-decoration:none;"&gt;Within the Bond Fund allocation, MFS includes underlying funds 
with varying degrees of geographic (potentially including emerging market), interest rate and credit 
exposure, including exposure to below investment grade quality debt instruments. A portion of the fund&#x2019;s 
assets may also be allocated to the Money Market Fund.&lt;/p&gt;&lt;p style="margin-top:revert; margin-bottom:revert; font-size:10.0pt; font-family:Serif; font-style:normal; text-align:justify; color:#000000; font-weight:normal; text-decoration:none;"&gt;MFS 
normally invests the underlying funds&#x2019; assets across different industries, sectors, countries, and 
regions, but MFS may invest a significant percentage of the underlying funds' assets in issuers in a 
single industry, sector, country, or region.  &lt;/p&gt;&lt;p style="margin-top:revert; margin-bottom:revert;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;"&gt;As of May 
27, 2026, the fund&#x2019;s approximate long-term strategic allocation among asset classes was:&lt;/p&gt;&lt;table cellpadding="0" cellspacing="0" style="border-collapse:collapse" width="100%"&gt;&lt;tr style="font-size:1pt;"&gt;&lt;td style="width:73.5%;"&gt;&#160;&lt;/td&gt;&lt;td style="width:26.5%;"&gt;&#160;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td style="vertical-align:bottom; border-bottom:0.5pt; border-bottom-style:solid; border-bottom-color:#000000; border-top:0.5pt; border-top-style:solid; border-top-color:#000000; border-right:0.5pt; border-right-style:solid; border-right-color:#000000;"&gt;&lt;p style="font-size:9.0pt; font-family:Sans-Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;"&gt;Equity Funds and Non-Traditional Funds&lt;/p&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom; border-bottom:0.5pt; border-bottom-style:solid; border-bottom-color:#000000; border-top:0.5pt; border-top-style:solid; border-top-color:#000000; border-left:0.5pt; border-left-style:solid; border-left-color:#000000;"&gt;&lt;p style="font-size:9.0pt; font-family:Sans-Serif; font-style:normal; text-align:center; color:#000000; font-weight:normal; text-decoration:none;"&gt;95%&lt;/p&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td style="vertical-align:bottom; border-bottom:0.5pt; border-bottom-style:solid; border-bottom-color:#000000; border-top:0.5pt; border-top-style:solid; border-top-color:#000000; border-right:0.5pt; border-right-style:solid; border-right-color:#000000;"&gt;&lt;p style="font-size:9.0pt; font-family:Sans-Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;"&gt;Bond Funds and Money Market Fund&lt;/p&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom; border-bottom:0.5pt; border-bottom-style:solid; border-bottom-color:#000000; border-top:0.5pt; border-top-style:solid; border-top-color:#000000; border-left:0.5pt; border-left-style:solid; border-left-color:#000000;"&gt;&lt;p style="font-size:9.0pt; font-family:Sans-Serif; font-style:normal; text-align:center; color:#000000; font-weight:normal; text-decoration:none;"&gt;5%&lt;/p&gt;&lt;/td&gt;&lt;/tr&gt;&lt;/table&gt;&lt;p style="margin-top:revert; margin-bottom:revert; font-size:8.0pt; font-family:Sans-Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;"&gt;All percentages are rounded to the nearest percent.  &lt;/p&gt;&lt;p style="margin-top:revert; margin-bottom:revert; font-size:10.0pt; font-family:Serif; font-style:normal; text-align:justify; color:#000000; font-weight:normal; text-decoration:none;"&gt;MFS 
may deviate from the long-term strategic allocations set forth above; however, any deviation from the 
long-term strategic allocation is not expected to be greater than plus or minus 10% under normal market 
conditions. At no time, however, will the fund's investments in Equity Funds and Non-Traditional Funds 
exceed 99%. Additionally, the fund&#x2019;s allocation to Non-Traditional Funds will not typically exceed 
20% of the fund&#x2019;s assets. &lt;/p&gt;&lt;p style="margin-top:revert; margin-bottom:revert;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;"&gt;As of May 27, 2026, the fund&#x2019;s 
approximate strategic allocation among asset classes was:&lt;/p&gt;&lt;table cellpadding="0" cellspacing="0" style="border-collapse:collapse" width="100%"&gt;&lt;tr style="font-size:1pt;"&gt;&lt;td style="width:73.5%;"&gt;&#160;&lt;/td&gt;&lt;td style="width:26.5%;"&gt;&#160;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td style="vertical-align:bottom; border-bottom:0.5pt; border-bottom-style:solid; border-bottom-color:#000000; border-top:0.5pt; border-top-style:solid; border-top-color:#000000; border-right:0.5pt; border-right-style:solid; border-right-color:#000000;"&gt;&lt;p style="font-size:9.0pt; font-family:Sans-Serif; font-style:normal; text-align:left; color:#000000; font-weight:bold; text-decoration:none;"&gt;Equity Funds 
and Non-Traditional Funds&lt;/p&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom; border-bottom:0.5pt; border-bottom-style:solid; border-bottom-color:#000000; border-top:0.5pt; border-top-style:solid; border-top-color:#000000; border-left:0.5pt; border-left-style:solid; border-left-color:#000000;"&gt;&lt;p style="font-size:9.0pt; font-family:Sans-Serif; font-style:normal; text-align:center; color:#000000; font-weight:bold; text-decoration:none;"&gt;94.0%&lt;/p&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td style="vertical-align:bottom; border-bottom:0.5pt; border-bottom-style:solid; border-bottom-color:#000000; border-top:0.5pt; border-top-style:solid; border-top-color:#000000; border-right:0.5pt; border-right-style:solid; border-right-color:#000000;"&gt;&lt;p style="font-size:9.0pt; font-family:Sans-Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;"&gt;U.S. Equity Funds&lt;/p&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom; border-bottom:0.5pt; border-bottom-style:solid; border-bottom-color:#000000; border-top:0.5pt; border-top-style:solid; border-top-color:#000000; border-left:0.5pt; border-left-style:solid; border-left-color:#000000;"&gt;&lt;p style="font-size:9.0pt; font-family:Sans-Serif; font-style:normal; text-align:center; color:#000000; font-weight:normal; text-decoration:none;"&gt;55.5%&lt;/p&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td style="vertical-align:bottom; border-bottom:0.5pt; border-bottom-style:solid; border-bottom-color:#000000; border-top:0.5pt; border-top-style:solid; border-top-color:#000000; border-right:0.5pt; border-right-style:solid; border-right-color:#000000;"&gt;&lt;p style="font-size:9.0pt; font-family:Sans-Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;"&gt;International 
Equity Funds&lt;/p&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom; border-bottom:0.5pt; border-bottom-style:solid; border-bottom-color:#000000; border-top:0.5pt; border-top-style:solid; border-top-color:#000000; border-left:0.5pt; border-left-style:solid; border-left-color:#000000;"&gt;&lt;p style="font-size:9.0pt; font-family:Sans-Serif; font-style:normal; text-align:center; color:#000000; font-weight:normal; text-decoration:none;"&gt;28.5%&lt;/p&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td style="vertical-align:bottom; border-bottom:0.5pt; border-bottom-style:solid; border-bottom-color:#000000; border-top:0.5pt; border-top-style:solid; border-top-color:#000000; border-right:0.5pt; border-right-style:solid; border-right-color:#000000;"&gt;&lt;p style="font-size:9.0pt; font-family:Sans-Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;"&gt;Non-Traditional Funds&lt;/p&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom; border-bottom:0.5pt; border-bottom-style:solid; border-bottom-color:#000000; border-top:0.5pt; border-top-style:solid; border-top-color:#000000; border-left:0.5pt; border-left-style:solid; border-left-color:#000000;"&gt;&lt;p style="font-size:9.0pt; font-family:Sans-Serif; font-style:normal; text-align:center; color:#000000; font-weight:normal; text-decoration:none;"&gt;10.0%&lt;/p&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td style="vertical-align:bottom; border-bottom:0.5pt; border-bottom-style:solid; border-bottom-color:#000000; border-top:0.5pt; border-top-style:solid; border-top-color:#000000; border-right:0.5pt; border-right-style:solid; border-right-color:#000000;"&gt;&lt;p style="font-size:9.0pt; font-family:Sans-Serif; font-style:normal; text-align:left; color:#000000; font-weight:bold; text-decoration:none;"&gt;Bond 
Funds and Money Market Fund&lt;/p&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom; border-bottom:0.5pt; border-bottom-style:solid; border-bottom-color:#000000; border-top:0.5pt; border-top-style:solid; border-top-color:#000000; border-left:0.5pt; border-left-style:solid; border-left-color:#000000;"&gt;&lt;p style="font-size:9.0pt; font-family:Sans-Serif; font-style:normal; text-align:center; color:#000000; font-weight:bold; text-decoration:none;"&gt;6.0%&lt;/p&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td style="vertical-align:bottom; border-bottom:0.5pt; border-bottom-style:solid; border-bottom-color:#000000; border-top:0.5pt; border-top-style:solid; border-top-color:#000000; border-right:0.5pt; border-right-style:solid; border-right-color:#000000;"&gt;&lt;p style="font-size:9.0pt; font-family:Sans-Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;"&gt;Bond Funds&lt;/p&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom; border-bottom:0.5pt; border-bottom-style:solid; border-bottom-color:#000000; border-top:0.5pt; border-top-style:solid; border-top-color:#000000; border-left:0.5pt; border-left-style:solid; border-left-color:#000000;"&gt;&lt;p style="font-size:9.0pt; font-family:Sans-Serif; font-style:normal; text-align:center; color:#000000; font-weight:normal; text-decoration:none;"&gt;5.0%&lt;/p&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td style="vertical-align:bottom; border-bottom:0.5pt; border-bottom-style:solid; border-bottom-color:#000000; border-top:0.5pt; border-top-style:solid; border-top-color:#000000; border-right:0.5pt; border-right-style:solid; border-right-color:#000000;"&gt;&lt;p style="font-size:9.0pt; font-family:Sans-Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;"&gt;Money 
Market Fund&lt;/p&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom; border-bottom:0.5pt; border-bottom-style:solid; border-bottom-color:#000000; border-top:0.5pt; border-top-style:solid; border-top-color:#000000; border-left:0.5pt; border-left-style:solid; border-left-color:#000000;"&gt;&lt;p style="font-size:9.0pt; font-family:Sans-Serif; font-style:normal; text-align:center; color:#000000; font-weight:normal; text-decoration:none;"&gt;1.0%&lt;/p&gt;&lt;/td&gt;&lt;/tr&gt;&lt;/table&gt;&lt;p style="margin-top:revert; margin-bottom:revert; font-size:8.0pt; font-family:Sans-Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;"&gt;All percentages are rounded to the nearest tenth of a percent.  As a result, the 
sum of the asset class allocations presented in the table may not total 100%.&lt;/p&gt;&lt;p style="margin-top:revert; margin-bottom:revert; font-size:10.0pt; font-family:Serif; font-style:normal; text-align:justify; color:#000000; font-weight:normal; text-decoration:none;"&gt;The 
asset class allocations for the fund, as well as the underlying funds and their weightings, are based 
on an allocation strategy designed for investors with the approximate retirement year in the fund&#x2019;s 
name. Investors should also consider their age, personal circumstances, risk tolerance, and overall investment 
strategy and allocation. The asset allocation strategy will become increasingly conservative over time, 
shifting more weight from Equity Funds and Non-Traditional Funds to Bond Funds and the Money Market Fund.&lt;/p&gt;&lt;p style="margin-top:revert; margin-bottom:revert; font-size:10.0pt; font-family:Serif; font-style:normal; text-align:justify; color:#000000; font-weight:normal; text-decoration:none;"&gt;Upon reaching its stated target year, the fund&#x2019;s allocation strategy will be 
aligned with the allocation strategy of MFS Lifetime Income &lt;/p&gt;&lt;p style="margin-top:revert; margin-bottom:revert; font-size:10.0pt; font-family:Serif; font-style:normal; text-align:justify; color:#000000; font-weight:normal; text-decoration:none;"&gt;Fund.  It is expected that the fund will be combined with 
MFS Lifetime Income Fund within five years of the date that its asset allocation strategy matches the 
asset allocation strategy of MFS Lifetime Income Fund.  MFS Lifetime Income Fund is designed for investors 
who intend to withdraw assets over an extended period of time or who want an investment with an asset 
allocation mix similar to MFS Lifetime Income Fund's long-term strategic asset allocation. The chart 
below illustrates how the asset allocation strategy of the fund will change over time.&lt;/p&gt;&lt;p style="margin-top:revert; margin-bottom:revert; font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"&gt;&lt;img alt="" src="img_ab28cadbada74f2.jpg"/&gt;&lt;/p&gt;</oef:StrategyNarrativeTextBlock>
    <oef:RiskTextBlock
      contextRef="Context_20260430_20260430_S000104920Member_PrincipalRisks2_S000104920Summary1Member"
      id="ixv-1070">&lt;p style="margin-top:revert; margin-bottom:revert; font-size:11.0pt; font-family:Arial; text-align:left; color:#000000; font-weight:bold; text-decoration:none;"&gt;Principal Risks &lt;/p&gt;&lt;p style="margin-top:revert; margin-bottom:revert; font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;"&gt;As with any mutual  fund, 
the fund may not achieve its objective and/or you could lose money on your investment in the fund, including 
near or after the target year. There is no guarantee that the fund will provide income at or through 
retirement. An investment in the fund is not a bank deposit and is not insured or guaranteed by the Federal 
Deposit Insurance Corporation or any other governmental agency.&lt;/p&gt;&lt;p style="margin-top:revert; margin-bottom:revert; font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;"&gt;The principal 
risks of investing in the fund are:&lt;/p&gt;</oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Context_20260430_20260430_S000104920Member_RiskLoseMoneyMember_S000104920Summary1Member"
      id="ixv-28557">As with any mutual  fund, 
the fund may not achieve its objective and/or you could lose money on your investment in the fund, including 
near or after the target year.</oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Context_20260430_20260430_S000104920Member_RiskNotInsuredMember_S000104920Summary1Member"
      id="ixv-28558">An investment in the fund is not a bank deposit and is not insured or guaranteed by the Federal 
Deposit Insurance Corporation or any other governmental agency.</oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Context_20260430_20260430_S000104920Member_AllocationRisk2_S000104920Summary1Member"
      id="ixv-1074">&lt;p style="margin-top:revert; margin-bottom:revert; font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;"&gt;Allocation Risk: &lt;/span&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"&gt; 
&lt;/span&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"&gt; MFS' assessment of the risk/return potential of asset classes and underlying 
funds, and the resulting allocation among asset classes and underlying funds, may not produce the intended 
results and/or can lead to an investment focus that results in the fund underperforming other funds with 
similar investment strategies and/or underperforming the markets in which the fund invests.&lt;/span&gt;&lt;/p&gt;</oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Context_20260430_20260430_S000104920Member_UnderlyingFundsRisk2_S000104920Summary1Member"
      id="ixv-1079">&lt;p style="margin-top:revert; margin-bottom:revert; font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;"&gt;Underlying 
Funds Risk: &lt;/span&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"&gt; MFS' strategy of investing in underlying funds exposes the 
fund to the risks of the underlying funds. Each underlying fund pursues its own investment objective 
and strategies and may not achieve its objective.  In addition to the fees and expenses the fund bears 
directly, shareholders of the fund will indirectly bear the fees and expenses of the underlying funds.&lt;/span&gt;&lt;/p&gt;</oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Context_20260430_20260430_S000104920Member_InvestmentSelectionRisk2_S000104920Summary1Member"
      id="ixv-1083">&lt;p style="margin-top:revert; margin-bottom:revert; font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;"&gt;Investment 
Selection Risk: &lt;/span&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"&gt; MFS' investment analysis, including its assessment of the 
intrinsic valuation of issuers, its development and use of quantitative models, and its selection of 
investments may not produce the intended results and/or can lead to an investment focus that results 
in the fund underperforming other funds with similar investment strategies and/or underperforming the 
markets in which the fund invests. The quantitative models used by MFS (both proprietary and third-party) 
may not produce the intended results for a variety of reasons, including the factors used in the models, 
the weight placed on each factor in the models, changes from the market factors' historical trends, changing 
sources of market return or market risk, and technical issues in the design, development, implementation, 
application, and maintenance of the models (e.g., incomplete, stale, or inaccurate data, human error, 
programming or other software issues, coding errors, and technology failures).&lt;/span&gt;&lt;/p&gt;</oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Context_20260430_20260430_S000104920Member_EquityMarketRiskCompanyRisk2_S000104920Summary1Member"
      id="ixv-1087">&lt;p style="margin-top:revert; margin-bottom:revert; font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;"&gt;Equity 
Market Risk/Company Risk:&lt;/span&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"&gt;  &lt;/span&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"&gt;Equity markets are volatile 
and can decline significantly in response to changes in, or investor perceptions of, issuer, market, 
economic, industry, political, regulatory, geopolitical, environmental, public health, and other conditions. 
 These conditions can affect a single issuer or type of security, issuers within a broad market sector, 
industry or geographic region, or the equity markets in general.  Certain events can have a dramatic 
adverse effect on equity markets and may lead to periods of high volatility in an equity market or a 
segment of an equity market.  The value of an investment held by the fund may decline due to factors 
directly related to the issuer.&lt;/span&gt;&lt;/p&gt;</oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Context_20260430_20260430_S000104920Member_GrowthCompanyRisk2_S000104920Summary1Member"
      id="ixv-1092">&lt;p style="margin-top:revert; margin-bottom:revert; font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;"&gt;Growth Company Risk: &lt;/span&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"&gt; 
The stocks of growth companies can be more sensitive to the company&#x2019;s earnings and more volatile than 
the market in general.&lt;/span&gt;&lt;/p&gt;</oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Context_20260430_20260430_S000104920Member_ValueCompanyRisk2_S000104920Summary1Member"
      id="ixv-1096">&lt;p style="margin-top:revert; margin-bottom:revert; font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;"&gt;Value Company Risk: &lt;/span&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"&gt; &lt;/span&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"&gt;The 
stocks of value companies can continue to be undervalued for long periods of time and not realize their 
expected value and can be more volatile than the market in general.&lt;/span&gt;&lt;/p&gt;&#160;</oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Context_20260430_20260430_S000104920Member_DebtMarketRisk2_S000104920Summary1Member"
      id="ixv-1102">&lt;p style="margin-top:revert; margin-bottom:revert; font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;"&gt;Debt Market 
Risk:  &lt;/span&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"&gt;Debt markets can be volatile and can decline significantly in response to changes 
in, or investor perceptions of, issuer, market, economic, industry, political, regulatory, geopolitical, 
environmental, public health, and other conditions.  These conditions can affect a single instrument, 
issuer, or borrower, a particular type of instrument, issuer, or borrower, a segment of the debt markets 
or the debt markets generally. Certain events can have a dramatic adverse effect on debt markets and 
may lead to periods of high volatility and reduced liquidity in a debt market or segment of a debt market. 
 &lt;/span&gt;&lt;/p&gt;</oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Context_20260430_20260430_S000104920Member_InterestRateRisk2_S000104920Summary1Member"
      id="ixv-1106">&lt;p style="margin-top:revert; margin-bottom:revert; font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;"&gt;Interest Rate Risk: &lt;/span&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"&gt; &lt;/span&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"&gt;In general, 
the price of a debt instrument falls when interest rates rise and rises when interest rates fall. Interest 
rate risk is generally greater for instruments with longer maturities or durations, or that do not pay 
current interest.&lt;/span&gt;&lt;/p&gt;</oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Context_20260430_20260430_S000104920Member_CreditRisk2_S000104920Summary1Member"
      id="ixv-1111">&lt;p style="margin-top:revert; margin-bottom:revert; font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;"&gt;Credit Risk: &lt;/span&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"&gt; The 
price of a debt instrument depends, in part, on the credit quality of the issuer, borrower, counterparty, 
or other entity responsible for payment, or underlying collateral or assets and the terms of the instrument. 
The price of a debt instrument can decline in response to changes in, or perceptions of, the financial 
condition of the issuer, borrower, counterparty, or other entity, or underlying collateral or assets, 
or changes in, or perceptions of, specific or general market, economic, industry, political, regulatory, 
geopolitical, environmental, public health, and other conditions. Debt instruments may be more susceptible 
to downgrades or defaults during economic downturns or similar periods of economic stress, which in turn 
could negatively affect the market value and liquidity of a debt instrument.&lt;/span&gt;&lt;/p&gt;&lt;p style="margin-top:revert; margin-bottom:revert; font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;"&gt;Below 
investment grade quality debt instruments (commonly referred to as &#x201c;high yield securities&#x201d; or &#x201c;junk 
bonds&#x201d;) can involve a substantially greater risk of default or can already be in default, and their 
values can decline significantly. Below investment grade quality debt instruments are regarded as having 
predominantly speculative characteristics. Below investment grade quality debt instruments tend to be 
more sensitive to adverse news about the issuer, or the market or economy in general, than higher quality 
debt instruments.&lt;/p&gt;</oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Context_20260430_20260430_S000104920Member_PrepaymentExtensionRisk2_S000104920Summary1Member"
      id="ixv-1116">&lt;p style="margin-top:revert; margin-bottom:revert; font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;"&gt;Prepayment/Extension Risk: &lt;/span&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"&gt; &lt;/span&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"&gt;Instruments 
subject to prepayment and/or extension can reduce the potential for gain for the instrument&#x2019;s holders 
if the instrument is prepaid and increase the potential for loss if the maturity of the instrument is 
extended.  &lt;/span&gt;&lt;/p&gt;</oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Context_20260430_20260430_S000104920Member_Inflation-AdjustedDebtInstrumentsRisk2_S000104920Summary1Member"
      id="ixv-1121">&lt;p style="margin-top:revert; margin-bottom:revert; font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;"&gt;Inflation-Adjusted Debt Instruments Risk: &lt;/span&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"&gt; 
&lt;/span&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"&gt;Interest payments on inflation-adjusted debt instruments can be unpredictable 
and vary &lt;/span&gt;&lt;/p&gt;&lt;p style="margin-top:revert; margin-bottom:revert; font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;"&gt;based on the level of inflation. In addition, inflation-adjusted debt instruments 
may lose value in the event the actual rate of inflation is different than the rate of the applicable 
inflation index. If inflation is negative, principal and income can both decline.&lt;/p&gt;</oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Context_20260430_20260430_S000104920Member_FocusRisk2_S000104920Summary1Member"
      id="ixv-1134">&lt;p style="margin-top:revert; margin-bottom:revert; font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;"&gt;Focus Risk: 
 &lt;/span&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"&gt;Issuers in a single industry, sector, country, or region can react similarly to 
market, currency, political, economic, regulatory, geopolitical, environmental, public health, and other 
conditions, and the fund's performance will be affected by the conditions in the industries, sectors, 
countries, and regions to which the fund is exposed.  Furthermore, investments in particular industries, 
sectors, countries, or regions may be more volatile than the broader market as a whole.  &lt;/span&gt;&lt;/p&gt;</oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Context_20260430_20260430_S000104920Member_ForeignRisk2_S000104920Summary1Member"
      id="ixv-1138">&lt;p style="margin-top:revert; margin-bottom:revert; font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;"&gt;Foreign 
Risk: &lt;/span&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"&gt; Exposure to foreign markets through issuers or currencies can involve additional 
risks relating to market, economic, industry, political, regulatory, geopolitical, environmental, public 
health, and other conditions. These factors can make foreign investments, especially those tied economically 
to emerging markets or countries subject to sanctions or the threat of new or modified sanctions, more 
volatile and less liquid than U.S. investments. In addition, foreign markets can react differently to 
these conditions than the U.S. market. &lt;/span&gt;&lt;/p&gt;</oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Context_20260430_20260430_S000104920Member_EmergingMarketsRisk2_S000104920Summary1Member"
      id="ixv-1142">&lt;p style="margin-top:revert; margin-bottom:revert; font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;"&gt;Emerging Markets Risk:&lt;/span&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"&gt; 
 Investments tied economically to emerging markets, especially frontier markets, can involve additional 
and greater risks than the risks associated with investments in developed markets.  Emerging markets 
can have less developed markets&lt;/span&gt;&lt;span style="font-size:9.0pt; font-family:Sans-Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"&gt;,&lt;/span&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"&gt; greater custody and operational 
risk, less developed legal, regulatory, and accounting systems, greater government involvement in the 
economy, greater risk of new or inconsistent government treatment of or restrictions on issuers and instruments, 
and greater political, social, geopolitical, and economic instability than developed markets. &lt;/span&gt;&lt;/p&gt;</oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Context_20260430_20260430_S000104920Member_CurrencyRisk2_S000104920Summary1Member"
      id="ixv-1148">&lt;p style="margin-top:revert; margin-bottom:revert; font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;"&gt;Currency 
Risk: &lt;/span&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"&gt; The value of foreign currencies relative to the U.S. dollar fluctuates in response 
to market, economic, industry, political, regulatory, geopolitical, environmental, public health, and 
other conditions, and changes in currency exchange rates impact the financial condition of companies 
or other issuers and may change the value in U.S. dollars of investments denominated in foreign currencies. 
 &lt;/span&gt;&lt;/p&gt;</oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Context_20260430_20260430_S000104920Member_RealEstate-RelatedInvestmentRisk2_S000104920Summary1Member"
      id="ixv-1152">&lt;p style="margin-top:revert; margin-bottom:revert; font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;"&gt;Real Estate-Related Investment Risk: &lt;/span&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"&gt;The risks 
of investing in real estate-related securities include certain risks associated with the direct ownership 
of real estate and the real estate industry in general. These include risks related to general, regional 
and local economic conditions; difficulties in valuing and disposing of real estate; &lt;/span&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"&gt;fluctuations 
in interest rates and property tax rates; shifts in zoning laws, environmental regulations and other 
governmental action; cash flow dependency; increased operating expenses; lack of availability of mortgage 
funds; losses due to natural disasters; overbuilding; losses due to casualty or condemnation; changes 
in property values and rental rates; the management skill and creditworthiness of the real estate investment 
trust (REIT) manager; and other factors.  The securities of smaller real estate-related issuers can be 
more volatile and less liquid than securities of larger issuers and their issuers can have more limited 
financial resources.&lt;/span&gt;&lt;/p&gt;</oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Context_20260430_20260430_S000104920Member_Commodity-RelatedInvestmentsRisk2_S000104920Summary1Member"
      id="ixv-1157">&lt;p style="margin-top:revert; margin-bottom:revert; font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;"&gt;Commodity-Related Investments Risk:  &lt;/span&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"&gt;The 
value of commodity-related investments may be more volatile than the value of equity securities or debt 
instruments and may be affected by factors such as changes in overall market movements, commodity index 
volatility, changes in interest rates, currency fluctuations, geopolitical events, or factors affecting 
a particular industry or commodity. The price of a commodity-related investment may be affected by demand/supply 
imbalances in the market for the commodity. &lt;/span&gt;&lt;/p&gt;</oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Context_20260430_20260430_S000104920Member_When-IssuedDelayedDeliveryandForwardCommitmentTransactionRisk2_S000104920Summary1Member"
      id="ixv-1161">&lt;p style="margin-top:revert; margin-bottom:revert; font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;"&gt;When-Issued, 
Delayed Delivery, and Forward Commitment Transaction Risk: &lt;/span&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"&gt;The purchaser in a when-issued, 
delayed delivery or forward commitment transaction assumes the rights and risks of ownership, including 
the risks of price and yield fluctuations and the risk that the security will not be issued or delivered 
as anticipated.  When-issued, delayed delivery, and forward commitment transactions can involve leverage. 
To be announced (TBA) transactions may significantly increase the fund's portfolio turnover rate.&lt;/span&gt;&lt;/p&gt;</oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Context_20260430_20260430_S000104920Member_DerivativesRisk2_S000104920Summary1Member"
      id="ixv-1165">&lt;p style="margin-top:revert; margin-bottom:revert; font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;"&gt;Derivatives 
Risk: &lt;/span&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"&gt; &lt;/span&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"&gt;Derivatives can be highly volatile and involve risks in addition 
to the risks of the underlying indicator(s) on which the derivative is based. Gains or losses from derivatives 
can be substantially greater than the derivatives&#x2019; original cost.  Derivatives can involve leverage.&lt;/span&gt;&lt;/p&gt;</oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Context_20260430_20260430_S000104920Member_LeveragingRisk2_S000104920Summary1Member"
      id="ixv-1170">&lt;p style="margin-top:revert; margin-bottom:revert; font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;"&gt;Leveraging 
Risk: &lt;/span&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"&gt; &lt;/span&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"&gt;Leverage involves investment exposure in an amount exceeding 
the initial investment. Leverage can cause increased volatility by magnifying gains or losses. &lt;/span&gt;&lt;/p&gt;</oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Context_20260430_20260430_S000104920Member_CounterpartyandThirdPartyRisk2_S000104920Summary1Member"
      id="ixv-1175">&lt;p style="margin-top:revert; margin-bottom:revert; font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;"&gt;Counterparty 
and Third Party Risk: &lt;/span&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"&gt; &lt;/span&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"&gt;Transactions involving a 
counterparty or third party other than the issuer of the instrument are subject to the credit risk of 
the counterparty or third party, and to the counterparty&#x2019;s or third party&#x2019;s ability or willingness 
to perform in accordance with the terms of the transaction.&lt;/span&gt;&lt;/p&gt;</oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Context_20260430_20260430_S000104920Member_LiquidityRisk2_S000104920Summary1Member"
      id="ixv-1180">&lt;p style="margin-top:revert; margin-bottom:revert; font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;"&gt;Liquidity 
Risk: &lt;/span&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"&gt; &lt;/span&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"&gt;It may be difficult to value, and it may not be possible to 
sell, certain investments, types of investments, and/or investments in certain segments of the market, 
and the fund may have to sell certain of these investments at prices or times that are not advantageous 
in order to meet redemptions or other cash needs.  &lt;/span&gt;&lt;/p&gt;</oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Context_20260430_20260430_S000104920Member_LargeShareholderRisk2_S000104920Summary1Member"
      id="ixv-1185">&lt;p style="margin-top:revert; margin-bottom:revert; font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;"&gt;Large Shareholder 
Risk:  &lt;/span&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"&gt;From time to time, shareholders of the fund (which may include institutional investors, 
financial intermediaries, or other MFS funds) may make relatively large redemptions or purchases of fund 
shares.  These transactions may cause the fund to sell securities or invest additional cash, as the case 
may be, at disadvantageous prices.  Redemptions of a large number of shares also may increase transaction 
and other costs or have adverse tax consequences for shareholders of the fund by requiring a sale of 
portfolio securities.  Purchases of a large number of shares may adversely affect the fund's performance 
to the extent that it takes time to invest new cash and the fund maintains a larger cash position than 
it ordinarily would.&lt;/span&gt;&lt;/p&gt;</oef:RiskTextBlock>
    <oef:BarChartAndPerformanceTableHeading
      contextRef="Context_20260430_20260430_S000104920Member_S000104920Summary1Member"
      id="ixv-28559">Performance Information</oef:BarChartAndPerformanceTableHeading>
    <oef:PerformanceNarrativeTextBlock
      contextRef="Context_20260430_20260430_S000104920Member_S000104920Summary1Member"
      id="ixv-1190">&lt;p style="margin-top:revert; margin-bottom:revert; font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"&gt;The bar 
chart and performance table are not included because the fund has not had a full calendar year of operations. 
 Once the fund has commenced operations, updated performance information will be available online at 
&lt;/span&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;"&gt;mfs.com&lt;/span&gt;&lt;span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"&gt;&#160;or by calling 1-800-225-2606.  Past performance 
(before and after taxes) does not necessarily indicate how the fund will perform in the future.&lt;/span&gt;&lt;/p&gt;</oef:PerformanceNarrativeTextBlock>
    <oef:PerformanceAvailabilityWebSiteAddress
      contextRef="Context_20260430_20260430_S000104920Member_S000104920Summary1Member"
      id="ixv-28560">mfs.com</oef:PerformanceAvailabilityWebSiteAddress>
    <oef:PerformanceAvailabilityPhone
      contextRef="Context_20260430_20260430_S000104920Member_S000104920Summary1Member"
      id="ixv-28561">1-800-225-2606</oef:PerformanceAvailabilityPhone>
    <dei:DocumentType contextRef="Context_20260430_20260430" id="ixv-28564">485BPOS</dei:DocumentType>
    <dei:DocumentEffectiveDate contextRef="Context_20260430_20260430" id="ixv-28565">2026-05-19</dei:DocumentEffectiveDate>
    <dei:DocumentPeriodEndDate contextRef="Context_20260430_20260430" id="ixv-28566">2026-04-30</dei:DocumentPeriodEndDate>
    <dei:EntityCentralIndexKey contextRef="Context_20260430_20260430" id="ixv-28567">0001330967</dei:EntityCentralIndexKey>
    <dei:DocumentCreationDate contextRef="Context_20260430_20260430" id="ixv-28568">2026-05-18</dei:DocumentCreationDate>
    <dei:AmendmentFlag contextRef="Context_20260430_20260430" id="ixv-28569">false</dei:AmendmentFlag>
    <oef:ShareholderFeesTableTextBlock
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    <oef:ExpensesDeferredChargesTextBlock
      contextRef="Context_20260430_20260430_C000275574Member_S000104920Member_S000104920Summary1Member"
      id="ixv-28905">This contingent deferred sales charge (CDSC) applies to shares purchased without 
an initial sales charge and redeemed within 18 months of purchase.</oef:ExpensesDeferredChargesTextBlock>
    <oef:FeeWaiverOrReimbursementOverAssetsDateOfTermination
      contextRef="Context_20260430_20260430_C000275574Member_S000104920Member_S000104920Summary1Member"
      id="ixv-28906">August 
31, 2027</oef:FeeWaiverOrReimbursementOverAssetsDateOfTermination>
    <oef:FeeWaiverOrReimbursementOverAssetsDateOfTermination
      contextRef="Context_20260430_20260430_C000275577Member_S000104920Member_S000104920Summary1Member"
      id="ixv-28907">August 
31, 2027</oef:FeeWaiverOrReimbursementOverAssetsDateOfTermination>
    <oef:FeeWaiverOrReimbursementOverAssetsDateOfTermination
      contextRef="Context_20260430_20260430_C000275576Member_S000104920Member_S000104920Summary1Member"
      id="ixv-28908">August 
31, 2027</oef:FeeWaiverOrReimbursementOverAssetsDateOfTermination>
    <oef:FeeWaiverOrReimbursementOverAssetsDateOfTermination
      contextRef="Context_20260430_20260430_C000275575Member_S000104920Member_S000104920Summary1Member"
      id="ixv-28909">August 
31, 2027</oef:FeeWaiverOrReimbursementOverAssetsDateOfTermination>
    <oef:FeeWaiverOrReimbursementOverAssetsDateOfTermination
      contextRef="Context_20260430_20260430_C000275578Member_S000104920Member_S000104920Summary1Member"
      id="ixv-28910">August 
31, 2027</oef:FeeWaiverOrReimbursementOverAssetsDateOfTermination>
    <oef:FeeWaiverOrReimbursementOverAssetsDateOfTermination
      contextRef="Context_20260430_20260430_C000275573Member_S000104920Member_S000104920Summary1Member"
      id="ixv-28911">August 
31, 2027</oef:FeeWaiverOrReimbursementOverAssetsDateOfTermination>
    <oef:FeeWaiverOrReimbursementOverAssetsDateOfTermination
      contextRef="Context_20260430_20260430_C000275572Member_S000104920Member_S000104920Summary1Member"
      id="ixv-28912">August 
31, 2027</oef:FeeWaiverOrReimbursementOverAssetsDateOfTermination>
    <oef:FeeWaiverOrReimbursementOverAssetsDateOfTermination
      contextRef="Context_20260430_20260430_C000275571Member_S000104920Member_S000104920Summary1Member"
      id="ixv-28913">August 
31, 2027</oef:FeeWaiverOrReimbursementOverAssetsDateOfTermination>
    <cik0001330967:CustomRisksTableTextBlock
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    <link:footnoteLink
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        <link:footnote id="fn1_" xlink:label="fn1_" xlink:role="http://www.xbrl.org/2003/role/footnote" xlink:type="resource" xml:lang="en-US"><xhtml:span style="font-size:8.0pt; font-family:Sans-Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">This contingent deferred sales charge (CDSC) applies to shares purchased without 
an initial sales charge and redeemed within 18 months of purchase.</xhtml:span></link:footnote>
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        <link:loc xlink:href="#_89_" xlink:label="_89_" xlink:type="locator"/>
        <link:loc xlink:href="#_90_" xlink:label="_90_" xlink:type="locator"/>
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        <link:footnote id="fn2_" xlink:label="fn2_" xlink:role="http://www.xbrl.org/2003/role/footnote" xlink:type="resource" xml:lang="en-US"><xhtml:span style="font-size:8.0pt; font-family:Sans-Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Massachusetts Financial Services Company (MFS) has agreed in writing to bear the 
fund's expenses, excluding management fees, distribution and service fees, interest, taxes, extraordinary 
expenses, brokerage and transaction costs, investment-related expenses, and fees and expenses associated 
with investments in investment companies and other similar investment vehicles, or make payment to the 
fund, such that "Other Expenses" do not exceed 0.00% of the class' average daily net assets annually 
for each of Class A, Class C, Class I, Class R1, Class R2, Class R3, and Class R4 shares, and (0.14)% 
of the class' average daily net assets annually for Class R6 shares. This written agreement will continue 
until modified by the fund's Board of Trustees, but such agreement will continue until at least August 
31, 2027.</xhtml:span></link:footnote>
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