<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.26.3</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>1110</ContextCount>
  <ElementCount>86</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>true</FootnotesReported>
  <SegmentCount>198</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>2</UnitCount>
  <MyReports>
    <Report instance="c485bpos.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>010000 - Disclosure - Form N-1A Cover</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/rr/role/N1aCover</Role>
      <ShortName>Form N-1A Cover</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="c485bpos.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>010000 - Document - Document and Entity Information {Elements}</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.MFS.com/20260531/role/DocumentAndEntityInformation1</Role>
      <ShortName>Document and Entity Information</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="c485bpos.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>010002 - Disclosure - Investment Objectives and Goals</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/rr/role/RiskReturn</Role>
      <ShortName>Investment Objectives and Goals</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="c485bpos.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>true</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>010003 - Disclosure - Fees and Expenses</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/rr/role/FeesAndExpenses</Role>
      <ShortName>Fees and Expenses</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="c485bpos.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>010004 - Disclosure - Investment Strategy</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/rr/role/InvestmentStrategy</Role>
      <ShortName>Investment Strategy</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="c485bpos.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>true</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>010004 - Schedule - Investment Risks {Unlabeled}</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.MFS.com/20260531/role/RRCustomRiskRole30</Role>
      <ShortName>Investment Risks</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="c485bpos.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>true</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>010006 - Disclosure - Performance Management</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/rr/role/PerformanceManagement</Role>
      <ShortName>Performance Management</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="c485bpos.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>020050 - Disclosure - Annual Total Returns</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/rr/role/BarChartData</Role>
      <ShortName>Annual Total Returns</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="c485bpos.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>020102 - Disclosure - Risk/Return Detail Data (MFS Aggressive Growth Allocation Fund) {Elements}</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.MFS.com/20260531/role/RRDetailData2</Role>
      <ShortName>Risk/Return Detail Data (MFS Aggressive Growth Allocation Fund)</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="c485bpos.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>020104 - Disclosure - Risk/Return Detail Data (MFS Blended Research Growth Equity Fund) {Elements}</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.MFS.com/20260531/role/RRDetailData4</Role>
      <ShortName>Risk/Return Detail Data (MFS Blended Research Growth Equity Fund)</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="c485bpos.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>020106 - Disclosure - Risk/Return Detail Data (MFS Blended Research Small Cap Equity Fund) {Elements}</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.MFS.com/20260531/role/RRDetailData6</Role>
      <ShortName>Risk/Return Detail Data (MFS Blended Research Small Cap Equity Fund)</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="c485bpos.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>020108 - Disclosure - Risk/Return Detail Data (MFS Blended Research Mid Cap Equity Fund) {Elements}</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.MFS.com/20260531/role/RRDetailData8</Role>
      <ShortName>Risk/Return Detail Data (MFS Blended Research Mid Cap Equity Fund)</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="c485bpos.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>020110 - Disclosure - Risk/Return Detail Data (MFS Blended Research Value Equity Fund) {Elements}</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.MFS.com/20260531/role/RRDetailData10</Role>
      <ShortName>Risk/Return Detail Data (MFS Blended Research Value Equity Fund)</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="c485bpos.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>020112 - Disclosure - Risk/Return Detail Data (MFS Conservative Allocation Fund) {Elements}</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.MFS.com/20260531/role/RRDetailData12</Role>
      <ShortName>Risk/Return Detail Data (MFS Conservative Allocation Fund)</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="c485bpos.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>020114 - Disclosure - Risk/Return Detail Data (MFS Emerging Markets Equity Fund) {Elements}</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.MFS.com/20260531/role/RRDetailData14</Role>
      <ShortName>Risk/Return Detail Data (MFS Emerging Markets Equity Fund)</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="c485bpos.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>020116 - Disclosure - Risk/Return Detail Data (MFS Growth Allocation Fund) {Elements}</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.MFS.com/20260531/role/RRDetailData16</Role>
      <ShortName>Risk/Return Detail Data (MFS Growth Allocation Fund)</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="c485bpos.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>020118 - Disclosure - Risk/Return Detail Data (MFS International Diversification Fund) {Elements}</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.MFS.com/20260531/role/RRDetailData18</Role>
      <ShortName>Risk/Return Detail Data (MFS International Diversification Fund)</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="c485bpos.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>020120 - Disclosure - Risk/Return Detail Data (MFS International Growth Fund) {Elements}</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.MFS.com/20260531/role/RRDetailData20</Role>
      <ShortName>Risk/Return Detail Data (MFS International Growth Fund)</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="c485bpos.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>020122 - Disclosure - Risk/Return Detail Data (MFS International Intrinsic Equity Fund) {Elements}</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.MFS.com/20260531/role/RRDetailData22</Role>
      <ShortName>Risk/Return Detail Data (MFS International Intrinsic Equity Fund)</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="c485bpos.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>020124 - Disclosure - Risk/Return Detail Data (MFS International Value Fund) {Elements}</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.MFS.com/20260531/role/RRDetailData24</Role>
      <ShortName>Risk/Return Detail Data (MFS International Value Fund)</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report instance="c485bpos.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>020126 - Disclosure - Risk/Return Detail Data (MFS Managed Wealth Fund) {Elements}</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.MFS.com/20260531/role/RRDetailData26</Role>
      <ShortName>Risk/Return Detail Data (MFS Managed Wealth Fund)</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>21</Position>
    </Report>
    <Report instance="c485bpos.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>020128 - Disclosure - Risk/Return Detail Data (MFS Moderate Allocation Fund) {Elements}</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.MFS.com/20260531/role/RRDetailData28</Role>
      <ShortName>Risk/Return Detail Data (MFS Moderate Allocation Fund)</ShortName>
      <MenuCategory>Risk/Return</MenuCategory>
      <Position>22</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <InputFiles>
    <File>c485bpos-20260925.xsd</File>
    <File>c485bpos-20260925_def.xml</File>
    <File>c485bpos-20260925_lab.xml</File>
    <File>c485bpos-20260925_pre.xml</File>
    <File doctype="485BPOS" isN1a="true" isOEF="true" isRRorOEF="true" isUsgaap="true" original="c485bpos.htm">c485bpos.htm</File>
  </InputFiles>
  <SupplementalFiles>
    <File>img_0b5c8674a44c4f4.jpg</File>
    <File>img_159864480f664f10.jpg</File>
    <File>img_1cb7f20db7cf4f8.jpg</File>
    <File>img_256ebe90ee164f3.jpg</File>
    <File>img_297390a30a3e4f7.jpg</File>
    <File>img_2b5222c239224f14.jpg</File>
    <File>img_39f7d77c4f334f13.jpg</File>
    <File>img_5bed86d804f24f2.jpg</File>
    <File>img_9e682bf35c374f6.jpg</File>
    <File>img_a1a366fab9b54f12.jpg</File>
    <File>img_b0f8893caab74f15.jpg</File>
    <File>img_c34d2299877f4f9.jpg</File>
    <File>img_e3b65354125c4f11.jpg</File>
    <File>img_e718f797787a4f5.jpg</File>
    <File>img_e80557cdbbcf4f2.jpg</File>
  </SupplementalFiles>
  <BaseTaxonomies>
    <BaseTaxonomy items="134">http://xbrl.sec.gov/dei/2025</BaseTaxonomy>
    <BaseTaxonomy items="22">http://xbrl.sec.gov/fnd/2025</BaseTaxonomy>
    <BaseTaxonomy items="3542">http://xbrl.sec.gov/oef/2025</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>false</HasCalculationLinkbase>
</FilingSummary>
