<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.23.1</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>148</ContextCount>
  <ElementCount>250</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>false</FootnotesReported>
  <SegmentCount>58</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>7</UnitCount>
  <MyReports>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>0000001 - Document - Document and entity information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/Documentandentityinformation</Role>
      <ShortName>Document and entity information</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>0000002 - Statement - Unaudited condensed consolidated balance sheets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/Unauditedcondensedconsolidatedbalancesheets</Role>
      <ShortName>Unaudited condensed consolidated balance sheets</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>0000003 - Statement - Unaudited condensed consolidated balance sheets (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/UnauditedcondensedconsolidatedbalancesheetsParenthetical</Role>
      <ShortName>Unaudited condensed consolidated balance sheets (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>0000004 - Statement - Unaudited condensed consolidated statements of operations</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/Unauditedcondensedconsolidatedstatementsofoperations</Role>
      <ShortName>Unaudited condensed consolidated statements of operations</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>0000005 - Statement - Unaudited condensed consolidated statements of comprehensive income or loss</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/Unauditedcondensedconsolidatedstatementsofcomprehensiveincomeorloss</Role>
      <ShortName>Unaudited condensed consolidated statements of comprehensive income or loss</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>0000006 - Statement - Unaudited condensed consolidated statements of stockholders' equity or deficit - shares</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/Unauditedcondensedconsolidatedstatementsofstockholdersequityordeficitshares</Role>
      <ShortName>Unaudited condensed consolidated statements of stockholders' equity or deficit - shares</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>0000007 - Statement - Unaudited condensed consolidated statements of stockholders' equity or deficit - amounts</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/Unauditedcondensedconsolidatedstatementsofstockholdersequityordeficitamounts</Role>
      <ShortName>Unaudited condensed consolidated statements of stockholders' equity or deficit - amounts</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>0000008 - Statement - Unaudited condensed consolidated statements of cash flows</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/Unauditedcondensedconsolidatedstatementsofcashflows</Role>
      <ShortName>Unaudited condensed consolidated statements of cash flows</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>0000009 - Disclosure - Nature of operations and presentation of financial statements</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/Natureofoperationsandpresentationoffinancialstatements</Role>
      <ShortName>Nature of operations and presentation of financial statements</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>0000010 - Disclosure - Earnings per share</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/Earningspershare</Role>
      <ShortName>Earnings per share</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>0000011 - Disclosure - Segment financial information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/Segmentfinancialinformation</Role>
      <ShortName>Segment financial information</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>0000012 - Disclosure - Supplemental disclosures of cash flow information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/Supplementaldisclosuresofcashflowinformation</Role>
      <ShortName>Supplemental disclosures of cash flow information</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>0000013 - Disclosure - Inventory</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/Inventory</Role>
      <ShortName>Inventory</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>0000014 - Disclosure - Other intangible assets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/Otherintangibleassets</Role>
      <ShortName>Other intangible assets</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>0000015 - Disclosure - Commitments and contingencies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/Commitmentsandcontingencies</Role>
      <ShortName>Commitments and contingencies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>0000016 - Disclosure - Debt</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/Debt</Role>
      <ShortName>Debt</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>0000017 - Disclosure - Accumulated other comprehensive income or loss</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/Accumulatedothercomprehensiveincomeorloss</Role>
      <ShortName>Accumulated other comprehensive income or loss</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>0000018 - Disclosure - Stock-based compensation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/Stockbasedcompensation</Role>
      <ShortName>Stock-based compensation</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>0000019 - Disclosure - Other income or expense, net</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/Otherincomeorexpensenet</Role>
      <ShortName>Other income or expense, net</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>0000020 - Disclosure - Income taxes</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/Incometaxes</Role>
      <ShortName>Income taxes</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>0000021 - Disclosure - Derivative and hedging activities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/Derivativeandhedgingactivities</Role>
      <ShortName>Derivative and hedging activities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>21</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>0000022 - Disclosure - Financial instruments and fair value measurements</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/Financialinstrumentsandfairvaluemeasurements</Role>
      <ShortName>Financial instruments and fair value measurements</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>22</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>0000023 - Disclosure - Nature of operations and presentation of financial statements (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/NatureofoperationsandpresentationoffinancialstatementsPolicies</Role>
      <ShortName>Nature of operations and presentation of financial statements (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <Position>23</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>0000024 - Disclosure - Earnings per share (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/EarningspershareTables</Role>
      <ShortName>Earnings per share (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://us.avtr.com/role/Earningspershare</ParentRole>
      <Position>24</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>0000025 - Disclosure - Segment financial information (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/SegmentfinancialinformationTables</Role>
      <ShortName>Segment financial information (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://us.avtr.com/role/Segmentfinancialinformation</ParentRole>
      <Position>25</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>0000026 - Disclosure - Supplemental disclosures of cash flow information (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/SupplementaldisclosuresofcashflowinformationTables</Role>
      <ShortName>Supplemental disclosures of cash flow information (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://us.avtr.com/role/Supplementaldisclosuresofcashflowinformation</ParentRole>
      <Position>26</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>0000027 - Disclosure - Inventory (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/InventoryTables</Role>
      <ShortName>Inventory (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://us.avtr.com/role/Inventory</ParentRole>
      <Position>27</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>0000028 - Disclosure - Other intangible assets (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/OtherintangibleassetsTables</Role>
      <ShortName>Other intangible assets (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://us.avtr.com/role/Otherintangibleassets</ParentRole>
      <Position>28</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>0000029 - Disclosure - Debt (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/DebtTables</Role>
      <ShortName>Debt (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://us.avtr.com/role/Debt</ParentRole>
      <Position>29</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>0000030 - Disclosure - Accumulated other comprehensive income or loss (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/AccumulatedothercomprehensiveincomeorlossTables</Role>
      <ShortName>Accumulated other comprehensive income or loss (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://us.avtr.com/role/Accumulatedothercomprehensiveincomeorloss</ParentRole>
      <Position>30</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>0000031 - Disclosure - Stock-based compensation (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/StockbasedcompensationTables</Role>
      <ShortName>Stock-based compensation (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://us.avtr.com/role/Stockbasedcompensation</ParentRole>
      <Position>31</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>0000032 - Disclosure - Other income or expense, net (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/OtherincomeorexpensenetTables</Role>
      <ShortName>Other income or expense, net (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://us.avtr.com/role/Otherincomeorexpensenet</ParentRole>
      <Position>32</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>0000033 - Disclosure - Income taxes (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/IncometaxesTables</Role>
      <ShortName>Income taxes (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://us.avtr.com/role/Incometaxes</ParentRole>
      <Position>33</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>0000034 - Disclosure - Derivative and hedging activities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/DerivativeandhedgingactivitiesTables</Role>
      <ShortName>Derivative and hedging activities (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://us.avtr.com/role/Derivativeandhedgingactivities</ParentRole>
      <Position>34</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>0000035 - Disclosure - Financial instruments and fair value measurements (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/FinancialinstrumentsandfairvaluemeasurementsTables</Role>
      <ShortName>Financial instruments and fair value measurements (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://us.avtr.com/role/Financialinstrumentsandfairvaluemeasurements</ParentRole>
      <Position>35</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>0000036 - Disclosure - Nature of operations and presentation of financial statements (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/NatureofoperationsandpresentationoffinancialstatementsDetails</Role>
      <ShortName>Nature of operations and presentation of financial statements (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://us.avtr.com/role/NatureofoperationsandpresentationoffinancialstatementsPolicies</ParentRole>
      <Position>36</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>0000037 - Disclosure - Earnings per share - reconciliation (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/EarningspersharereconciliationDetails</Role>
      <ShortName>Earnings per share - reconciliation (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>37</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>0000038 - Disclosure - Segment financial information - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/SegmentfinancialinformationNarrativeDetails</Role>
      <ShortName>Segment financial information - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>38</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>0000039 - Disclosure - Segment financial information - reportable segments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/SegmentfinancialinformationreportablesegmentsDetails</Role>
      <ShortName>Segment financial information - reportable segments (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>39</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>0000040 - Disclosure - Segment financial information - reconciliation of segment profitability measure (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/SegmentfinancialinformationreconciliationofsegmentprofitabilitymeasureDetails</Role>
      <ShortName>Segment financial information - reconciliation of segment profitability measure (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>40</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>0000041 - Disclosure - Segment financial information - product lines (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/SegmentfinancialinformationproductlinesDetails</Role>
      <ShortName>Segment financial information - product lines (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>41</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>0000042 - Disclosure - Supplemental disclosures of cash flow information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/SupplementaldisclosuresofcashflowinformationDetails</Role>
      <ShortName>Supplemental disclosures of cash flow information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://us.avtr.com/role/SupplementaldisclosuresofcashflowinformationTables</ParentRole>
      <Position>42</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>0000043 - Disclosure - Inventory (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/InventoryDetails</Role>
      <ShortName>Inventory (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://us.avtr.com/role/InventoryTables</ParentRole>
      <Position>43</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>0000044 - Disclosure - Other intangible assets (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/OtherintangibleassetsDetails</Role>
      <ShortName>Other intangible assets (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://us.avtr.com/role/OtherintangibleassetsTables</ParentRole>
      <Position>44</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>0000045 - Disclosure - Commitments and contingencies (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/CommitmentsandcontingenciesDetails</Role>
      <ShortName>Commitments and contingencies (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://us.avtr.com/role/Commitmentsandcontingencies</ParentRole>
      <Position>45</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>0000046 - Disclosure - Debt (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/DebtDetails</Role>
      <ShortName>Debt (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://us.avtr.com/role/DebtTables</ParentRole>
      <Position>46</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>0000047 - Disclosure - Debt - other information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/DebtotherinformationDetails</Role>
      <ShortName>Debt - other information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>47</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>0000048 - Disclosure - Accumulated other comprehensive income or loss (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/AccumulatedothercomprehensiveincomeorlossDetails</Role>
      <ShortName>Accumulated other comprehensive income or loss (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://us.avtr.com/role/AccumulatedothercomprehensiveincomeorlossTables</ParentRole>
      <Position>48</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>0000049 - Disclosure - Stock-based compensation - expense (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/StockbasedcompensationexpenseDetails</Role>
      <ShortName>Stock-based compensation - expense (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>49</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>0000050 - Disclosure - Stock-based compensation - stock option rollforward information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/StockbasedcompensationstockoptionrollforwardinformationDetails</Role>
      <ShortName>Stock-based compensation - stock option rollforward information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>50</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>0000051 - Disclosure - Stock-based compensation - non-option award rollforward (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/StockbasedcompensationnonoptionawardrollforwardDetails</Role>
      <ShortName>Stock-based compensation - non-option award rollforward (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>51</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>0000052 - Disclosure - Stock-based compensation - other information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/StockbasedcompensationotherinformationDetails</Role>
      <ShortName>Stock-based compensation - other information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>52</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>0000053 - Disclosure - Other income or expense, net (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/OtherincomeorexpensenetDetails</Role>
      <ShortName>Other income or expense, net (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://us.avtr.com/role/OtherincomeorexpensenetTables</ParentRole>
      <Position>53</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>0000054 - Disclosure - Income taxes (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/IncometaxesDetails</Role>
      <ShortName>Income taxes (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://us.avtr.com/role/IncometaxesTables</ParentRole>
      <Position>54</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>0000055 - Disclosure - Derivative and hedging activities - Outstanding Interest Rate Derivatives (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/DerivativeandhedgingactivitiesOutstandingInterestRateDerivativesDetails</Role>
      <ShortName>Derivative and hedging activities - Outstanding Interest Rate Derivatives (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>55</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>0000056 - Disclosure - Derivative and hedging activities - Effect on AOCI (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/DerivativeandhedgingactivitiesEffectonAOCIDetails</Role>
      <ShortName>Derivative and hedging activities - Effect on AOCI (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>56</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>0000057 - Disclosure - Derivative and hedging activities - Effect on Income Statement (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/DerivativeandhedgingactivitiesEffectonIncomeStatementDetails</Role>
      <ShortName>Derivative and hedging activities - Effect on Income Statement (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>57</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R58.htm</HtmlFileName>
      <LongName>0000058 - Disclosure - Derivative and hedging activities - Derivative Instruments Classification on Balance Sheet (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/DerivativeandhedgingactivitiesDerivativeInstrumentsClassificationonBalanceSheetDetails</Role>
      <ShortName>Derivative and hedging activities - Derivative Instruments Classification on Balance Sheet (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>58</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R59.htm</HtmlFileName>
      <LongName>0000059 - Disclosure - Derivative and hedging activities - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/DerivativeandhedgingactivitiesNarrativeDetails</Role>
      <ShortName>Derivative and hedging activities - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>59</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R60.htm</HtmlFileName>
      <LongName>0000060 - Disclosure - Derivative and hedging activities - Gain (Loss) on Net Investment Hedges (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/DerivativeandhedgingactivitiesGainLossonNetInvestmentHedgesDetails</Role>
      <ShortName>Derivative and hedging activities - Gain (Loss) on Net Investment Hedges (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://us.avtr.com/role/DerivativeandhedgingactivitiesTables</ParentRole>
      <Position>60</Position>
    </Report>
    <Report instance="avtr-20230331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R61.htm</HtmlFileName>
      <LongName>0000061 - Disclosure - Financial instruments and fair value measurements (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://us.avtr.com/role/FinancialinstrumentsandfairvaluemeasurementsDetails</Role>
      <ShortName>Financial instruments and fair value measurements (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://us.avtr.com/role/FinancialinstrumentsandfairvaluemeasurementsTables</ParentRole>
      <Position>61</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="Warning">[ix-0514-Hidden-Fact-Eligible-For-Transform] WARN: 1 fact(s) appearing in ix:hidden were eligible for transformation: us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1 -  avtr-20230331.htm 4</Log>
  </Logs>
  <InputFiles>
    <File doctype="10-Q" original="avtr-20230331.htm">avtr-20230331.htm</File>
    <File>a2023q1ex311.htm</File>
    <File>a2023q1ex312.htm</File>
    <File>a2023q1ex321.htm</File>
    <File>a2023q1ex322.htm</File>
    <File>avtr-20230331.xsd</File>
    <File>avtr-20230331_cal.xml</File>
    <File>avtr-20230331_def.xml</File>
    <File>avtr-20230331_lab.xml</File>
    <File>avtr-20230331_pre.xml</File>
    <File>finalavantor-amendmentno.htm</File>
  </InputFiles>
  <SupplementalFiles>
    <File>avtr-20230331_g1.jpg</File>
  </SupplementalFiles>
  <BaseTaxonomies>
    <BaseTaxonomy items="633">http://fasb.org/us-gaap/2023</BaseTaxonomy>
    <BaseTaxonomy items="30">http://xbrl.sec.gov/dei/2023</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
