<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.26.1</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>1111</ContextCount>
  <ElementCount>27</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>true</FootnotesReported>
  <SegmentCount>282</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>3</UnitCount>
  <MyReports>
    <Report instance="8defcfdc3c02f7d.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>030000 - Disclosure - Form N-CSR Cover</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/oef/role/NcsrCover</Role>
      <ShortName>Form N-CSR Cover</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="8defcfdc3c02f7d.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>030001 - Disclosure - Shareholder Report</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/oef/role/ShareholderReport</Role>
      <ShortName>Shareholder Report</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="8defcfdc3c02f7d.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>040020 - Disclosure - Shareholder Report, Holdings (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/oef/role/ShareholderReportHoldingsDetails</Role>
      <ShortName>Shareholder Report, Holdings (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <InputFiles>
    <File doctype="N-CSRS" isDefinitelyNotFs="true" isNcsr="true" isOEF="true" isRRorOEF="true" isUsgaap="true" original="8defcfdc3c02f7d.htm">8defcfdc3c02f7d.htm</File>
    <File>cik0000896435-20260804.xsd</File>
  </InputFiles>
  <SupplementalFiles>
    <File>chartimages_10266016.jpg</File>
    <File>chartimages_10266038.jpg</File>
    <File>chartimages_10266095.jpg</File>
    <File>chartimages_10266129.jpg</File>
    <File>chartimages_10266158.jpg</File>
    <File>chartimages_10266205.jpg</File>
    <File>chartimages_10266237.jpg</File>
    <File>chartimages_10266251.jpg</File>
    <File>chartimages_10266341.jpg</File>
    <File>chartimages_10266374.jpg</File>
    <File>chartimages_10266402.jpg</File>
    <File>chartimages_10266501.jpg</File>
    <File>chartimages_10266525.jpg</File>
    <File>chartimages_10266555.jpg</File>
    <File>chartimages_10266584.jpg</File>
    <File>chartimages_10266617.jpg</File>
    <File>chartimages_10266647.jpg</File>
    <File>chartimages_10266749.jpg</File>
    <File>chartimages_10266798.jpg</File>
    <File>chartimages_10266830.jpg</File>
    <File>chartimages_10266863.jpg</File>
    <File>chartimages_10266888.jpg</File>
    <File>chartimages_10266965.jpg</File>
    <File>chartimages_10266998.jpg</File>
    <File>chartimages_10267074.jpg</File>
    <File>chartimages_10267108.jpg</File>
    <File>chartimages_10267143.jpg</File>
    <File>chartimages_10267215.jpg</File>
    <File>chartimages_10267287.jpg</File>
    <File>chartimages_10267323.jpg</File>
    <File>chartimages_10267355.jpg</File>
    <File>chartimages_10267359.jpg</File>
    <File>chartimages_10267382.jpg</File>
    <File>chartimages_10267395.jpg</File>
    <File>chartimages_10267431.jpg</File>
    <File>chartimages_10267467.jpg</File>
    <File>chartimages_10267503.jpg</File>
    <File>chartimages_10267527.jpg</File>
    <File>chartimages_10267539.jpg</File>
    <File>chartimages_10267647.jpg</File>
    <File>chartimages_10267663.jpg</File>
    <File>chartimages_10267719.jpg</File>
    <File>chartimages_10267755.jpg</File>
    <File>chartimages_10267791.jpg</File>
    <File>chartimages_10267827.jpg</File>
    <File>chartimages_10267863.jpg</File>
    <File>chartimages_10267899.jpg</File>
    <File>chartimages_10267908.jpg</File>
    <File>chartimages_10267954.jpg</File>
    <File>chartimages_10267964.jpg</File>
    <File>chartimages_10268016.jpg</File>
    <File>chartimages_10268041.jpg</File>
    <File>chartimages_10268050.jpg</File>
    <File>chartimages_10268123.jpg</File>
    <File>chartimages_10268144.jpg</File>
    <File>chartimages_10268254.jpg</File>
    <File>images_2753.jpg</File>
    <File>images_2754.jpg</File>
    <File>img00b138cf1.jpg</File>
    <File>img0cab81841.jpg</File>
    <File>img1491e3bb1.jpg</File>
    <File>img14d1462c1.jpg</File>
    <File>img1af385a41.jpg</File>
    <File>img1e145a761.jpg</File>
    <File>img253cb8b11.jpg</File>
    <File>img25978c511.jpg</File>
    <File>img4b4946471.jpg</File>
    <File>img5d1a950a1.jpg</File>
    <File>img5efc62011.jpg</File>
    <File>img620f2d181.jpg</File>
    <File>img62406cad1.jpg</File>
    <File>img6cfcf90a1.jpg</File>
    <File>img6e824dc31.jpg</File>
    <File>img8ba59a291.jpg</File>
    <File>img8d91fa991.jpg</File>
    <File>img987be4c81.jpg</File>
    <File>img9db3791a1.jpg</File>
    <File>img9ef492121.jpg</File>
    <File>imga95df10a1.jpg</File>
    <File>imgb1b1f2e41.jpg</File>
    <File>imgbd57f5371.jpg</File>
    <File>imgcefbd7321.jpg</File>
    <File>imgd1d30f571.jpg</File>
    <File>imgd27baf551.jpg</File>
    <File>imge81b87651.jpg</File>
    <File>imge8b7bf131.jpg</File>
    <File>imge92960981.jpg</File>
    <File>imgedb326151.jpg</File>
    <File>imgf88c57701.jpg</File>
  </SupplementalFiles>
  <BaseTaxonomies>
    <BaseTaxonomy items="120">http://fasb.org/us-gaap/2025</BaseTaxonomy>
    <BaseTaxonomy items="68">http://xbrl.sec.gov/dei/2025</BaseTaxonomy>
    <BaseTaxonomy items="1852">http://xbrl.sec.gov/oef/2025</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>false</HasPresentationLinkbase>
  <HasCalculationLinkbase>false</HasCalculationLinkbase>
</FilingSummary>
