<?xml version='1.0' encoding='UTF-8'?>
<FilingSummary>
  <Version>3.2.0.727</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>143</ContextCount>
  <ElementCount>215</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>false</FootnotesReported>
  <SegmentCount>42</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>7</UnitCount>
  <MyReports>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>0001000 - Document - Document And Entity Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/DocumentAndEntityInformation</Role>
      <ShortName>Document And Entity Information</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>1001000 - Statement - Consolidated Statements Of Income</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/ConsolidatedStatementsOfIncome</Role>
      <ShortName>Consolidated Statements Of Income</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>1002000 - Statement - Consolidated Statements Of Comprehensive Income</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/ConsolidatedStatementsOfComprehensiveIncome</Role>
      <ShortName>Consolidated Statements Of Comprehensive Income</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>1003000 - Statement - Consolidated Balance Sheets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/ConsolidatedBalanceSheets</Role>
      <ShortName>Consolidated Balance Sheets</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>1003501 - Statement - Consolidated Balance Sheets (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/ConsolidatedBalanceSheetsParenthetical</Role>
      <ShortName>Consolidated Balance Sheets (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>1004000 - Statement - Consolidated Statements Of Cash Flows</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/ConsolidatedStatementsOfCashFlows</Role>
      <ShortName>Consolidated Statements Of Cash Flows</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>2101100 - Disclosure - Basis Of Presentation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/BasisOfPresentation</Role>
      <ShortName>Basis Of Presentation</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>2105100 - Disclosure - Proposed Merger with Merck KGaA</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/ProposedMergerWithMerckKgaa</Role>
      <ShortName>Proposed Merger with Merck KGaA</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>2108100 - Disclosure - Inventories</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/Inventories</Role>
      <ShortName>Inventories</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>2109100 - Disclosure - Intangible Assets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/IntangibleAssets</Role>
      <ShortName>Intangible Assets</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>2111100 - Disclosure - Debt</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/Debt</Role>
      <ShortName>Debt</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>2112100 - Disclosure - Financial Derivatives and Risk Management</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/FinancialDerivativesAndRiskManagement</Role>
      <ShortName>Financial Derivatives and Risk Management</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>2113100 - Disclosure - Company Operations By Business Unit</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/CompanyOperationsByBusinessUnit</Role>
      <ShortName>Company Operations By Business Unit</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>2114100 - Disclosure - Pension And Post-Retirement Benefits</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/PensionAndPostRetirementBenefits</Role>
      <ShortName>Pension And Post-Retirement Benefits</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>2116100 - Disclosure - Other Assets And Liabilities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/OtherAssetsAndLiabilities</Role>
      <ShortName>Other Assets And Liabilities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>2117100 - Disclosure - Other Charges</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/OtherCharges</Role>
      <ShortName>Other Charges</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>2118100 - Disclosure - Earnings Per Share</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/EarningsPerShare</Role>
      <ShortName>Earnings Per Share</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>2119100 - Disclosure - Share Repurchases</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/ShareRepurchases</Role>
      <ShortName>Share Repurchases</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>2120100 - Disclosure - Accumulated Other Comprehensive Income</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/AccumulatedOtherComprehensiveIncome</Role>
      <ShortName>Accumulated Other Comprehensive Income</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>2121100 - Disclosure - Contingent Liabilities And Commitments</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/ContingentLiabilitiesAndCommitments</Role>
      <ShortName>Contingent Liabilities And Commitments</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>2308301 - Disclosure - Inventories (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/InventoriesTables</Role>
      <ShortName>Inventories (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.sigmaaldrich.com/role/Inventories</ParentRole>
      <Position>21</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>2309301 - Disclosure - Intangible Assets (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/IntangibleAssetsTables</Role>
      <ShortName>Intangible Assets (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.sigmaaldrich.com/role/IntangibleAssets</ParentRole>
      <Position>22</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>2311301 - Disclosure - Debt (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/DebtTables</Role>
      <ShortName>Debt (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.sigmaaldrich.com/role/Debt</ParentRole>
      <Position>23</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>2312301 - Disclosure - Financial Derivatives and Risk Management (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/FinancialDerivativesAndRiskManagementTables</Role>
      <ShortName>Financial Derivatives and Risk Management (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.sigmaaldrich.com/role/FinancialDerivativesAndRiskManagement</ParentRole>
      <Position>24</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>2313301 - Disclosure - Company Operations By Business Unit (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/CompanyOperationsByBusinessUnitTables</Role>
      <ShortName>Company Operations By Business Unit (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.sigmaaldrich.com/role/CompanyOperationsByBusinessUnit</ParentRole>
      <Position>25</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>2314301 - Disclosure - Pension And Post-Retirement Benefits (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/PensionAndPostRetirementBenefitsTables</Role>
      <ShortName>Pension And Post-Retirement Benefits (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.sigmaaldrich.com/role/PensionAndPostRetirementBenefits</ParentRole>
      <Position>26</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>2316301 - Disclosure - Other Assets And Liabilities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/OtherAssetsAndLiabilitiesTables</Role>
      <ShortName>Other Assets And Liabilities (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.sigmaaldrich.com/role/OtherAssetsAndLiabilities</ParentRole>
      <Position>27</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>2317301 - Disclosure - Other Charges (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/OtherChargesTables</Role>
      <ShortName>Other Charges (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.sigmaaldrich.com/role/OtherCharges</ParentRole>
      <Position>28</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>2318301 - Disclosure - Earnings Per Share (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/EarningsPerShareTables</Role>
      <ShortName>Earnings Per Share (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.sigmaaldrich.com/role/EarningsPerShare</ParentRole>
      <Position>29</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>2320301 - Disclosure - Accumulated Other Comprehensive Income (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/AccumulatedOtherComprehensiveIncomeTables</Role>
      <ShortName>Accumulated Other Comprehensive Income (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.sigmaaldrich.com/role/AccumulatedOtherComprehensiveIncome</ParentRole>
      <Position>30</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>2405401 - Disclosure - Proposed Merger with Merck KGaA (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/ProposedMergerWithMerckKgaaDetails</Role>
      <ShortName>Proposed Merger with Merck KGaA (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.sigmaaldrich.com/role/ProposedMergerWithMerckKgaa</ParentRole>
      <Position>31</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>2408402 - Disclosure - Inventories (Principal Categories Of Inventories) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/InventoriesPrincipalCategoriesOfInventoriesDetails</Role>
      <ShortName>Inventories (Principal Categories Of Inventories) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.sigmaaldrich.com/role/InventoriesTables</ParentRole>
      <Position>32</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>2409402 - Disclosure - Intangible Assets (Amortizable And Unamortizable Intangible Assets) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/IntangibleAssetsAmortizableAndUnamortizableIntangibleAssetsDetails</Role>
      <ShortName>Intangible Assets (Amortizable And Unamortizable Intangible Assets) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.sigmaaldrich.com/role/IntangibleAssetsTables</ParentRole>
      <Position>33</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>2409403 - Disclosure - Intangible Assets (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/IntangibleAssetsNarrativeDetails</Role>
      <ShortName>Intangible Assets (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.sigmaaldrich.com/role/IntangibleAssetsTables</ParentRole>
      <Position>34</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>2409404 - Disclosure - Intangible Assets (Change In Net Goodwill) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/IntangibleAssetsChangeInNetGoodwillDetails</Role>
      <ShortName>Intangible Assets (Change In Net Goodwill) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.sigmaaldrich.com/role/IntangibleAssetsTables</ParentRole>
      <Position>35</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>2411402 - Disclosure - Debt (Schedule Of Notes Payable And Long-Term Debt) (Details)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.sigmaaldrich.com/role/DebtScheduleOfNotesPayableAndLongTermDebtDetails</Role>
      <ShortName>Debt (Schedule Of Notes Payable And Long-Term Debt) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.sigmaaldrich.com/role/DebtTables</ParentRole>
      <Position>36</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>2411403 - Disclosure - Debt (Notes Payable And Long-Term Debt - Additional Information) (Details)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.sigmaaldrich.com/role/DebtNotesPayableAndLongTermDebtAdditionalInformationDetails</Role>
      <ShortName>Debt (Notes Payable And Long-Term Debt - Additional Information) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.sigmaaldrich.com/role/DebtTables</ParentRole>
      <Position>37</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>2411404 - Disclosure - Debt (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/DebtNarrativeDetails</Role>
      <ShortName>Debt (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.sigmaaldrich.com/role/DebtTables</ParentRole>
      <Position>38</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>2412402 - Disclosure - Financial Derivatives and Risk Management (Fair Value of Derivatives) - Balance Sheet (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/FinancialDerivativesAndRiskManagementFairValueOfDerivativesBalanceSheetDetails</Role>
      <ShortName>Financial Derivatives and Risk Management (Fair Value of Derivatives) - Balance Sheet (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.sigmaaldrich.com/role/FinancialDerivativesAndRiskManagementTables</ParentRole>
      <Position>39</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>2412403 - Disclosure - Financial Derivatives and Risk Management (Schedule Of Gain Loss) - Income Statement (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/FinancialDerivativesAndRiskManagementScheduleOfGainLossIncomeStatementDetails</Role>
      <ShortName>Financial Derivatives and Risk Management (Schedule Of Gain Loss) - Income Statement (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.sigmaaldrich.com/role/FinancialDerivativesAndRiskManagementTables</ParentRole>
      <Position>40</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>2412404 - Disclosure - Financial Derivatives and Risk Management (General Cash Flow Hedge Information) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/FinancialDerivativesAndRiskManagementGeneralCashFlowHedgeInformationDetails</Role>
      <ShortName>Financial Derivatives and Risk Management (General Cash Flow Hedge Information) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.sigmaaldrich.com/role/FinancialDerivativesAndRiskManagementTables</ParentRole>
      <Position>41</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>2413402 - Disclosure - Company Operations By Business Unit (Net Sales For The Company's Business Units) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/CompanyOperationsByBusinessUnitNetSalesForCompanysBusinessUnitsDetails</Role>
      <ShortName>Company Operations By Business Unit (Net Sales For The Company's Business Units) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.sigmaaldrich.com/role/CompanyOperationsByBusinessUnitTables</ParentRole>
      <Position>42</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>2413403 - Disclosure - Company Operations By Business Unit (Geographic Financial Information - Net Sales To Unaffiliated Customers) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/CompanyOperationsByBusinessUnitGeographicFinancialInformationNetSalesToUnaffiliatedCustomersDetails</Role>
      <ShortName>Company Operations By Business Unit (Geographic Financial Information - Net Sales To Unaffiliated Customers) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.sigmaaldrich.com/role/CompanyOperationsByBusinessUnitTables</ParentRole>
      <Position>43</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>2413404 - Disclosure - Company Operations By Business Unit (Geographic Financial Information - Long-Lived Assets) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/CompanyOperationsByBusinessUnitGeographicFinancialInformationLongLivedAssetsDetails</Role>
      <ShortName>Company Operations By Business Unit (Geographic Financial Information - Long-Lived Assets) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.sigmaaldrich.com/role/CompanyOperationsByBusinessUnitTables</ParentRole>
      <Position>44</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>2414402 - Disclosure - Pension And Post-Retirement Benefits (Components Of The Net Periodic Benefit Costs) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/PensionAndPostRetirementBenefitsComponentsOfNetPeriodicBenefitCostsDetails</Role>
      <ShortName>Pension And Post-Retirement Benefits (Components Of The Net Periodic Benefit Costs) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.sigmaaldrich.com/role/PensionAndPostRetirementBenefitsTables</ParentRole>
      <Position>45</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>2414403 - Disclosure - Pension And Post-Retirement Benefits (Pension And Post-Retirement Benefits And Liabilities) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/PensionAndPostRetirementBenefitsPensionAndPostRetirementBenefitsAndLiabilitiesDetails</Role>
      <ShortName>Pension And Post-Retirement Benefits (Pension And Post-Retirement Benefits And Liabilities) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.sigmaaldrich.com/role/PensionAndPostRetirementBenefitsTables</ParentRole>
      <Position>46</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>2414404 - Disclosure - Pension And Post-Retirement Benefits (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/PensionAndPostRetirementBenefitsNarrativeDetails</Role>
      <ShortName>Pension And Post-Retirement Benefits (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.sigmaaldrich.com/role/PensionAndPostRetirementBenefitsTables</ParentRole>
      <Position>47</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>2416402 - Disclosure - Other Assets And Liabilities (Other Current Assets) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/OtherAssetsAndLiabilitiesOtherCurrentAssetsDetails</Role>
      <ShortName>Other Assets And Liabilities (Other Current Assets) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.sigmaaldrich.com/role/OtherAssetsAndLiabilitiesTables</ParentRole>
      <Position>48</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>2416403 - Disclosure - Other Assets And Liabilities (Other Assets) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/OtherAssetsAndLiabilitiesOtherAssetsDetails</Role>
      <ShortName>Other Assets And Liabilities (Other Assets) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.sigmaaldrich.com/role/OtherAssetsAndLiabilitiesTables</ParentRole>
      <Position>49</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>2416404 - Disclosure - Other Assets And Liabilities (Other Current Liabilities) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/OtherAssetsAndLiabilitiesOtherCurrentLiabilitiesDetails</Role>
      <ShortName>Other Assets And Liabilities (Other Current Liabilities) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.sigmaaldrich.com/role/OtherAssetsAndLiabilitiesTables</ParentRole>
      <Position>50</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>2416405 - Disclosure - Other Assets And Liabilities (Other Liabilities) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/OtherAssetsAndLiabilitiesOtherLiabilitiesDetails</Role>
      <ShortName>Other Assets And Liabilities (Other Liabilities) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.sigmaaldrich.com/role/OtherAssetsAndLiabilitiesTables</ParentRole>
      <Position>51</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>2417402 - Disclosure - Other Charges (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/OtherChargesDetails</Role>
      <ShortName>Other Charges (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.sigmaaldrich.com/role/OtherChargesTables</ParentRole>
      <Position>52</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>2418402 - Disclosure - Earnings Per Share (Shares Used In Calculation Of Earnings Per Share) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/EarningsPerShareSharesUsedInCalculationOfEarningsPerShareDetails</Role>
      <ShortName>Earnings Per Share (Shares Used In Calculation Of Earnings Per Share) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.sigmaaldrich.com/role/EarningsPerShareTables</ParentRole>
      <Position>53</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>2419401 - Disclosure - Share Repurchases (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/ShareRepurchasesDetails</Role>
      <ShortName>Share Repurchases (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.sigmaaldrich.com/role/ShareRepurchases</ParentRole>
      <Position>54</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>2420402 - Disclosure - Accumulated Other Comprehensive Income (Changes in Accumulated Other Comprehensive Income by Component) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/AccumulatedOtherComprehensiveIncomeChangesInAccumulatedOtherComprehensiveIncomeByComponentDetails</Role>
      <ShortName>Accumulated Other Comprehensive Income (Changes in Accumulated Other Comprehensive Income by Component) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.sigmaaldrich.com/role/AccumulatedOtherComprehensiveIncomeTables</ParentRole>
      <Position>55</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>2420403 - Disclosure - Accumulated Other Comprehensive Income (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/AccumulatedOtherComprehensiveIncomeNarrativeDetails</Role>
      <ShortName>Accumulated Other Comprehensive Income (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.sigmaaldrich.com/role/AccumulatedOtherComprehensiveIncomeTables</ParentRole>
      <Position>56</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>2421401 - Disclosure - Contingent Liabilities And Commitments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.sigmaaldrich.com/role/ContingentLiabilitiesAndCommitmentsDetails</Role>
      <ShortName>Contingent Liabilities And Commitments (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.sigmaaldrich.com/role/ContingentLiabilitiesAndCommitments</ParentRole>
      <Position>57</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <Logs>
    <Log type="Info">In ''Consolidated Balance Sheets'', column(s) 2, 4, 5, 6 are contained in other reports, so were removed by flow through suppression.</Log>
    <Log type="Info">In ''Consolidated Statements Of Cash Flows'', column(s) 1, 2 are contained in other reports, so were removed by flow through suppression.</Log>
  </Logs>
  <InputFiles>
    <File>sial-20150630.xml</File>
    <File>sial-20150630_cal.xml</File>
    <File>sial-20150630_def.xml</File>
    <File>sial-20150630_lab.xml</File>
    <File>sial-20150630_pre.xml</File>
    <File>sial-20150630.xsd</File>
  </InputFiles>
  <SupplementalFiles/>
  <BaseTaxonomies/>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>

