<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.25.4</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>475</ContextCount>
  <ElementCount>527</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>false</FootnotesReported>
  <SegmentCount>101</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>9</UnitCount>
  <MyReports>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>0000001 - Document - Cover page</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/Coverpage</Role>
      <ShortName>Cover page</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>0000002 - Document - Audit Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/AuditInformation</Role>
      <ShortName>Audit Information</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>9952151 - Statement - Consolidated Statements of Earnings</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/ConsolidatedStatementsofEarnings</Role>
      <ShortName>Consolidated Statements of Earnings</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>9952152 - Statement - Consolidated Statements of Comprehensive Income</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/ConsolidatedStatementsofComprehensiveIncome</Role>
      <ShortName>Consolidated Statements of Comprehensive Income</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>9952153 - Statement - Consolidated Statements of Financial Position</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/ConsolidatedStatementsofFinancialPosition</Role>
      <ShortName>Consolidated Statements of Financial Position</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>9952154 - Statement - Consolidated Statements of Financial Position Statement (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/ConsolidatedStatementsofFinancialPositionStatementParenthetical</Role>
      <ShortName>Consolidated Statements of Financial Position Statement (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>9952155 - Statement - Consolidated Statements of Changes in Equity</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/ConsolidatedStatementsofChangesinEquity</Role>
      <ShortName>Consolidated Statements of Changes in Equity</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>9952156 - Statement - Consolidated Statements of Cash Flows</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/ConsolidatedStatementsofCashFlows</Role>
      <ShortName>Consolidated Statements of Cash Flows</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>9952157 - Disclosure - Business Description</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/BusinessDescription</Role>
      <ShortName>Business Description</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>9952158 - Disclosure - Basis of Presentation and Summary of Significant Accounting Policies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/BasisofPresentationandSummaryofSignificantAccountingPolicies</Role>
      <ShortName>Basis of Presentation and Summary of Significant Accounting Policies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>9952159 - Disclosure - Acquisitions and Dispositions</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/AcquisitionsandDispositions</Role>
      <ShortName>Acquisitions and Dispositions</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>9952160 - Disclosure - Debt Securities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/DebtSecurities</Role>
      <ShortName>Debt Securities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>9952161 - Disclosure - Loan Receivables and Allowance for Credit Losses</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/LoanReceivablesandAllowanceforCreditLosses</Role>
      <ShortName>Loan Receivables and Allowance for Credit Losses</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>9952162 - Disclosure - Variable Interest Entities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/VariableInterestEntities</Role>
      <ShortName>Variable Interest Entities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>9952163 - Disclosure - Goodwill and Other Intangible Assets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/GoodwillandOtherIntangibleAssets</Role>
      <ShortName>Goodwill and Other Intangible Assets</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>9952164 - Disclosure - Deposits</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/Deposits</Role>
      <ShortName>Deposits</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>9952165 - Disclosure - Borrowings</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/Borrowings</Role>
      <ShortName>Borrowings</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>9952166 - Disclosure - Fair Value Measurements</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/FairValueMeasurements</Role>
      <ShortName>Fair Value Measurements</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>9952167 - Disclosure - Regulatory and Capital Adequacy</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/RegulatoryandCapitalAdequacy</Role>
      <ShortName>Regulatory and Capital Adequacy</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>9952168 - Disclosure - Employee Benefit Plans</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/EmployeeBenefitPlans</Role>
      <ShortName>Employee Benefit Plans</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>9952169 - Disclosure - Earnings Per Share</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/EarningsPerShare</Role>
      <ShortName>Earnings Per Share</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>21</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>9952170 - Disclosure - Equity and Other Stock Related Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/EquityandOtherStockRelatedInformation</Role>
      <ShortName>Equity and Other Stock Related Information</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>22</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>9952171 - Disclosure - Income Taxes</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/IncomeTaxes</Role>
      <ShortName>Income Taxes</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>23</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>9952172 - Disclosure - Parent Company Financial Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/ParentCompanyFinancialInformation</Role>
      <ShortName>Parent Company Financial Information</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>24</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>9952173 - Disclosure - Segment Reporting</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/SegmentReporting</Role>
      <ShortName>Segment Reporting</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>25</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>9952174 - Disclosure - Legal Proceedings and Regulatory Matters</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/LegalProceedingsandRegulatoryMatters</Role>
      <ShortName>Legal Proceedings and Regulatory Matters</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>26</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>995445 - Disclosure - Insider Trading Arrangements</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/ecd/role/InsiderTradingArrangements</Role>
      <ShortName>Insider Trading Arrangements</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>27</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>995447 - Disclosure - Insider Trading Policies and Procedures</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/ecd/role/InsiderTradingPoliciesProc</Role>
      <ShortName>Insider Trading Policies and Procedures</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>28</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>995550 - Disclosure - Cybersecurity Risk Management and Strategy Disclosure</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/cyd/role/CybersecurityRiskManagementAndStrategyDisclosure</Role>
      <ShortName>Cybersecurity Risk Management and Strategy Disclosure</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>29</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>9955511 - Disclosure - Basis of Presentation and Summary of Significant Accounting Policies (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/BasisofPresentationandSummaryofSignificantAccountingPoliciesPolicies</Role>
      <ShortName>Basis of Presentation and Summary of Significant Accounting Policies (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <ParentRole>http://www.synchronyfinancial.com/role/BasisofPresentationandSummaryofSignificantAccountingPolicies</ParentRole>
      <Position>30</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>9955512 - Disclosure - Acquisitions and Dispositions (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/AcquisitionsandDispositionsTables</Role>
      <ShortName>Acquisitions and Dispositions (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.synchronyfinancial.com/role/AcquisitionsandDispositions</ParentRole>
      <Position>31</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>9955513 - Disclosure - Debt Securities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/DebtSecuritiesTables</Role>
      <ShortName>Debt Securities (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.synchronyfinancial.com/role/DebtSecurities</ParentRole>
      <Position>32</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>9955514 - Disclosure - Loan Receivables and Allowance for Credit Losses (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/LoanReceivablesandAllowanceforCreditLossesTables</Role>
      <ShortName>Loan Receivables and Allowance for Credit Losses (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.synchronyfinancial.com/role/LoanReceivablesandAllowanceforCreditLosses</ParentRole>
      <Position>33</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>9955515 - Disclosure - Variable Interest Entities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/VariableInterestEntitiesTables</Role>
      <ShortName>Variable Interest Entities (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.synchronyfinancial.com/role/VariableInterestEntities</ParentRole>
      <Position>34</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>9955516 - Disclosure - Goodwill and Other Intangible Assets (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/GoodwillandOtherIntangibleAssetsTables</Role>
      <ShortName>Goodwill and Other Intangible Assets (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.synchronyfinancial.com/role/GoodwillandOtherIntangibleAssets</ParentRole>
      <Position>35</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>9955517 - Disclosure - Deposits (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/DepositsTables</Role>
      <ShortName>Deposits (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.synchronyfinancial.com/role/Deposits</ParentRole>
      <Position>36</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>9955518 - Disclosure - Borrowings (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/BorrowingsTables</Role>
      <ShortName>Borrowings (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.synchronyfinancial.com/role/Borrowings</ParentRole>
      <Position>37</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>9955519 - Disclosure - Fair Value Measurements (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/FairValueMeasurementsTables</Role>
      <ShortName>Fair Value Measurements (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.synchronyfinancial.com/role/FairValueMeasurements</ParentRole>
      <Position>38</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>9955520 - Disclosure - Regulatory and Capital Adequacy (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/RegulatoryandCapitalAdequacyTables</Role>
      <ShortName>Regulatory and Capital Adequacy (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.synchronyfinancial.com/role/RegulatoryandCapitalAdequacy</ParentRole>
      <Position>39</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>9955521 - Disclosure - Earnings Per Share (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/EarningsPerShareTables</Role>
      <ShortName>Earnings Per Share (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.synchronyfinancial.com/role/EarningsPerShare</ParentRole>
      <Position>40</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>9955522 - Disclosure - Equity and Other Stock Related Information (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/EquityandOtherStockRelatedInformationTables</Role>
      <ShortName>Equity and Other Stock Related Information (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.synchronyfinancial.com/role/EquityandOtherStockRelatedInformation</ParentRole>
      <Position>41</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>9955523 - Disclosure - Income Taxes (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/IncomeTaxesTables</Role>
      <ShortName>Income Taxes (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.synchronyfinancial.com/role/IncomeTaxes</ParentRole>
      <Position>42</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>9955524 - Disclosure - Parent Company Financial Information (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/ParentCompanyFinancialInformationTables</Role>
      <ShortName>Parent Company Financial Information (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.synchronyfinancial.com/role/ParentCompanyFinancialInformation</ParentRole>
      <Position>43</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>9955525 - Disclosure - Segment Reporting (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/SegmentReportingTables</Role>
      <ShortName>Segment Reporting (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.synchronyfinancial.com/role/SegmentReporting</ParentRole>
      <Position>44</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>9955527 - Disclosure - Basis of Presentation and Summary of Significant Accounting Policies - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/BasisofPresentationandSummaryofSignificantAccountingPoliciesNarrativeDetails</Role>
      <ShortName>Basis of Presentation and Summary of Significant Accounting Policies - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.synchronyfinancial.com/role/BasisofPresentationandSummaryofSignificantAccountingPoliciesPolicies</ParentRole>
      <Position>45</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>9955528 - Disclosure - Acquisitions and Dispositions - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/AcquisitionsandDispositionsNarrativeDetails</Role>
      <ShortName>Acquisitions and Dispositions - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>46</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>9955529 - Disclosure - Acquisitions and Dispositions - Schedule of Assets Acquired and Liabilities Assumed (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/AcquisitionsandDispositionsScheduleofAssetsAcquiredandLiabilitiesAssumedDetails</Role>
      <ShortName>Acquisitions and Dispositions - Schedule of Assets Acquired and Liabilities Assumed (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>47</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>9955530 - Disclosure - Debt Securities - Schedule of Available for Sale Securities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/DebtSecuritiesScheduleofAvailableforSaleSecuritiesDetails</Role>
      <ShortName>Debt Securities - Schedule of Available for Sale Securities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>48</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>9955531 - Disclosure - Debt Securities - Continuous Unrealized Losses (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/DebtSecuritiesContinuousUnrealizedLossesDetails</Role>
      <ShortName>Debt Securities - Continuous Unrealized Losses (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>49</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>9955532 - Disclosure - Debt Securities - Contractual Maturities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/DebtSecuritiesContractualMaturitiesDetails</Role>
      <ShortName>Debt Securities - Contractual Maturities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>50</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>9955534 - Disclosure - Loan Receivables and Allowance for Credit Losses - Loan Receivables (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/LoanReceivablesandAllowanceforCreditLossesLoanReceivablesDetails</Role>
      <ShortName>Loan Receivables and Allowance for Credit Losses - Loan Receivables (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>51</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>9955535 - Disclosure - Loan Receivables and Allowance for Credit Losses - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/LoanReceivablesandAllowanceforCreditLossesNarrativeDetails</Role>
      <ShortName>Loan Receivables and Allowance for Credit Losses - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.synchronyfinancial.com/role/LoanReceivablesandAllowanceforCreditLossesTables</ParentRole>
      <Position>52</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>9955536 - Disclosure - Loan Receivables and Allowance for Credit Losses - Allowance for Credit Losses (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/LoanReceivablesandAllowanceforCreditLossesAllowanceforCreditLossesDetails</Role>
      <ShortName>Loan Receivables and Allowance for Credit Losses - Allowance for Credit Losses (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>53</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>9955537 - Disclosure - Loan Receivables and Allowance for Credit Losses - Delinquent and Non Accrual Status (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/LoanReceivablesandAllowanceforCreditLossesDelinquentandNonAccrualStatusDetails</Role>
      <ShortName>Loan Receivables and Allowance for Credit Losses - Delinquent and Non Accrual Status (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>54</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>9955538 - Disclosure - Loan Receivables and Allowance for Credit Losses - Loan Credit Quality Indicators by Origination Year (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/LoanReceivablesandAllowanceforCreditLossesLoanCreditQualityIndicatorsbyOriginationYearDetails</Role>
      <ShortName>Loan Receivables and Allowance for Credit Losses - Loan Credit Quality Indicators by Origination Year (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>55</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>9955539 - Disclosure - Loan Receivables and Allowance for Credit Losses - Loans Entered into a Loan Modification Program (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/LoanReceivablesandAllowanceforCreditLossesLoansEnteredintoaLoanModificationProgramDetails</Role>
      <ShortName>Loan Receivables and Allowance for Credit Losses - Loans Entered into a Loan Modification Program (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>56</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>9955540 - Disclosure - Loan Receivables and Allowance for Credit Losses - Credit Quality Indicators (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/LoanReceivablesandAllowanceforCreditLossesCreditQualityIndicatorsDetails</Role>
      <ShortName>Loan Receivables and Allowance for Credit Losses - Credit Quality Indicators (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>57</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R58.htm</HtmlFileName>
      <LongName>9955541 - Disclosure - Loan Receivables and Allowance for Credit Losses - Schedule of Loans Modified in Past 12 Months And Still In Program (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/LoanReceivablesandAllowanceforCreditLossesScheduleofLoansModifiedinPast12MonthsAndStillInProgramDetails</Role>
      <ShortName>Loan Receivables and Allowance for Credit Losses - Schedule of Loans Modified in Past 12 Months And Still In Program (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>58</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R59.htm</HtmlFileName>
      <LongName>9955542 - Disclosure - Loan Receivables and Allowance for Credit Losses - Payment Defaults (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/LoanReceivablesandAllowanceforCreditLossesPaymentDefaultsDetails</Role>
      <ShortName>Loan Receivables and Allowance for Credit Losses - Payment Defaults (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>59</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R60.htm</HtmlFileName>
      <LongName>9955543 - Disclosure - Loan Receivables and Allowance for Credit Losses - Interest Income by Product (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/LoanReceivablesandAllowanceforCreditLossesInterestIncomebyProductDetails</Role>
      <ShortName>Loan Receivables and Allowance for Credit Losses - Interest Income by Product (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>60</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R61.htm</HtmlFileName>
      <LongName>9955544 - Disclosure - Variable Interest Entities - Summary of Assets and Liabilities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/VariableInterestEntitiesSummaryofAssetsandLiabilitiesDetails</Role>
      <ShortName>Variable Interest Entities - Summary of Assets and Liabilities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>61</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R62.htm</HtmlFileName>
      <LongName>9955545 - Disclosure - Variable Interest Entities - Schedule of Selected Financial Metrics of our Consolidated Securitization VIEs (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/VariableInterestEntitiesScheduleofSelectedFinancialMetricsofourConsolidatedSecuritizationVIEsDetails</Role>
      <ShortName>Variable Interest Entities - Schedule of Selected Financial Metrics of our Consolidated Securitization VIEs (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>62</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R63.htm</HtmlFileName>
      <LongName>9955546 - Disclosure - Variable Interest Entities - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/VariableInterestEntitiesNarrativeDetails</Role>
      <ShortName>Variable Interest Entities - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>63</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R64.htm</HtmlFileName>
      <LongName>9955547 - Disclosure - Variable Interest Entities - Schedule of Amortization Expense, Tax Credits and Other Tax Benefits Associated with Investments in Affordable Housing Properties (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/VariableInterestEntitiesScheduleofAmortizationExpenseTaxCreditsandOtherTaxBenefitsAssociatedwithInvestmentsinAffordableHousingPropertiesDetails</Role>
      <ShortName>Variable Interest Entities - Schedule of Amortization Expense, Tax Credits and Other Tax Benefits Associated with Investments in Affordable Housing Properties (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>64</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R65.htm</HtmlFileName>
      <LongName>9955548 - Disclosure - Goodwill and Other Intangible Assets Goodwill and Other Intangible Assets- Schedule of Goodwill (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/GoodwillandOtherIntangibleAssetsGoodwillandOtherIntangibleAssetsScheduleofGoodwillDetails</Role>
      <ShortName>Goodwill and Other Intangible Assets Goodwill and Other Intangible Assets- Schedule of Goodwill (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>65</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R66.htm</HtmlFileName>
      <LongName>9955549 - Disclosure - Goodwill and Other Intangible Assets (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/GoodwillandOtherIntangibleAssetsDetails</Role>
      <ShortName>Goodwill and Other Intangible Assets (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.synchronyfinancial.com/role/GoodwillandOtherIntangibleAssetsTables</ParentRole>
      <Position>66</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R67.htm</HtmlFileName>
      <LongName>9955550 - Disclosure - Goodwill and Other Intangible Assets Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/GoodwillandOtherIntangibleAssetsNarrativeDetails</Role>
      <ShortName>Goodwill and Other Intangible Assets Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>67</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R68.htm</HtmlFileName>
      <LongName>9955551 - Disclosure - Goodwill and Other Intangible Assets- Schedule of Finite-Lived Intangible Assets, Future Amortization Expense (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/GoodwillandOtherIntangibleAssetsScheduleofFiniteLivedIntangibleAssetsFutureAmortizationExpenseDetails</Role>
      <ShortName>Goodwill and Other Intangible Assets- Schedule of Finite-Lived Intangible Assets, Future Amortization Expense (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>68</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R69.htm</HtmlFileName>
      <LongName>9955552 - Disclosure - Deposits - Schedule of Deposits (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/DepositsScheduleofDepositsDetails</Role>
      <ShortName>Deposits - Schedule of Deposits (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>69</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R70.htm</HtmlFileName>
      <LongName>9955553 - Disclosure - Deposits - Maturity Schedule (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/DepositsMaturityScheduleDetails</Role>
      <ShortName>Deposits - Maturity Schedule (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>70</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R71.htm</HtmlFileName>
      <LongName>9955554 - Disclosure - Deposits - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/DepositsNarrativeDetails</Role>
      <ShortName>Deposits - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>71</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R72.htm</HtmlFileName>
      <LongName>9955555 - Disclosure - Borrowings - Borrowings Schedule (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/BorrowingsBorrowingsScheduleDetails</Role>
      <ShortName>Borrowings - Borrowings Schedule (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>72</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R73.htm</HtmlFileName>
      <LongName>9955556 - Disclosure - Borrowings - Borrowings Maturity Schedule (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/BorrowingsBorrowingsMaturityScheduleDetails</Role>
      <ShortName>Borrowings - Borrowings Maturity Schedule (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>73</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R74.htm</HtmlFileName>
      <LongName>9955557 - Disclosure - Borrowings - Senior Unsecured (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/BorrowingsSeniorUnsecuredDetails</Role>
      <ShortName>Borrowings - Senior Unsecured (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>74</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R75.htm</HtmlFileName>
      <LongName>9955558 - Disclosure - Borrowings - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/BorrowingsNarrativeDetails</Role>
      <ShortName>Borrowings - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>75</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R76.htm</HtmlFileName>
      <LongName>9955559 - Disclosure - Fair Value Measurement - Recurring Fair Value Measurements (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/FairValueMeasurementRecurringFairValueMeasurementsDetails</Role>
      <ShortName>Fair Value Measurement - Recurring Fair Value Measurements (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>76</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R77.htm</HtmlFileName>
      <LongName>9955561 - Disclosure - Fair Value Measurement - Fair Value Asset and Liabilities Carried at Other than Fair Value (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/FairValueMeasurementFairValueAssetandLiabilitiesCarriedatOtherthanFairValueDetails</Role>
      <ShortName>Fair Value Measurement - Fair Value Asset and Liabilities Carried at Other than Fair Value (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>77</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R78.htm</HtmlFileName>
      <LongName>9955562 - Disclosure - Fair Value Measurement - Equity Securities Without Readily Determinable Fair Values (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/FairValueMeasurementEquitySecuritiesWithoutReadilyDeterminableFairValuesDetails</Role>
      <ShortName>Fair Value Measurement - Equity Securities Without Readily Determinable Fair Values (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>78</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R79.htm</HtmlFileName>
      <LongName>9955563 - Disclosure - Regulatory and Capital Adequacy (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/RegulatoryandCapitalAdequacyDetails</Role>
      <ShortName>Regulatory and Capital Adequacy (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.synchronyfinancial.com/role/RegulatoryandCapitalAdequacyTables</ParentRole>
      <Position>79</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R80.htm</HtmlFileName>
      <LongName>9955564 - Disclosure - Employee Benefit Plans- Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/EmployeeBenefitPlansNarrativeDetails</Role>
      <ShortName>Employee Benefit Plans- Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>80</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R81.htm</HtmlFileName>
      <LongName>9955565 - Disclosure - Earnings Per Share - Basic and Diluted Earnings Per Share (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/EarningsPerShareBasicandDilutedEarningsPerShareDetails</Role>
      <ShortName>Earnings Per Share - Basic and Diluted Earnings Per Share (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>81</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R82.htm</HtmlFileName>
      <LongName>9955566 - Disclosure - Earnings Per Share - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/EarningsPerShareNarrativeDetails</Role>
      <ShortName>Earnings Per Share - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>82</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R83.htm</HtmlFileName>
      <LongName>9955567 - Disclosure - Equity and Other Stock Related Information - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/EquityandOtherStockRelatedInformationNarrativeDetails</Role>
      <ShortName>Equity and Other Stock Related Information - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>83</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R84.htm</HtmlFileName>
      <LongName>9955568 - Disclosure - Equity and Other Stock Related Information - Schedule of Preferred Stock (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/EquityandOtherStockRelatedInformationScheduleofPreferredStockDetails</Role>
      <ShortName>Equity and Other Stock Related Information - Schedule of Preferred Stock (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>84</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R85.htm</HtmlFileName>
      <LongName>9955569 - Disclosure - Income Taxes Income Taxes- Earnings Before Income Tax Provision (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/IncomeTaxesIncomeTaxesEarningsBeforeIncomeTaxProvisionDetails</Role>
      <ShortName>Income Taxes Income Taxes- Earnings Before Income Tax Provision (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>85</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R86.htm</HtmlFileName>
      <LongName>9955570 - Disclosure - Income Taxes- Significant Components of Income Tax Provision (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/IncomeTaxesSignificantComponentsofIncomeTaxProvisionDetails</Role>
      <ShortName>Income Taxes- Significant Components of Income Tax Provision (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>86</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R87.htm</HtmlFileName>
      <LongName>9955571 - Disclosure - Income Taxes- Effective Income Tax Rate Reconciliation (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/IncomeTaxesEffectiveIncomeTaxRateReconciliationDetails</Role>
      <ShortName>Income Taxes- Effective Income Tax Rate Reconciliation (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>87</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R88.htm</HtmlFileName>
      <LongName>9955572 - Disclosure - Income Taxes - Schedule of Income Taxes Paid (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/IncomeTaxesScheduleofIncomeTaxesPaidDetails</Role>
      <ShortName>Income Taxes - Schedule of Income Taxes Paid (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>88</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R89.htm</HtmlFileName>
      <LongName>9955573 - Disclosure - Income Taxes- Deferred Tax Assets and Liabilities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/IncomeTaxesDeferredTaxAssetsandLiabilitiesDetails</Role>
      <ShortName>Income Taxes- Deferred Tax Assets and Liabilities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>89</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R90.htm</HtmlFileName>
      <LongName>9955574 - Disclosure - Income Taxes- Unrecognized Tax Benefits (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/IncomeTaxesUnrecognizedTaxBenefitsDetails</Role>
      <ShortName>Income Taxes- Unrecognized Tax Benefits (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>90</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R91.htm</HtmlFileName>
      <LongName>9955575 - Disclosure - Parent Company Financial Information- Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/ParentCompanyFinancialInformationAdditionalInformationDetails</Role>
      <ShortName>Parent Company Financial Information- Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>91</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R92.htm</HtmlFileName>
      <LongName>9955576 - Disclosure - Parent Company Financial Information- Condensed Statements of Earnings (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/ParentCompanyFinancialInformationCondensedStatementsofEarningsDetails</Role>
      <ShortName>Parent Company Financial Information- Condensed Statements of Earnings (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>92</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R93.htm</HtmlFileName>
      <LongName>9955577 - Disclosure - Parent Company Financial Information- Condensed Statements of Financial Position (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/ParentCompanyFinancialInformationCondensedStatementsofFinancialPositionDetails</Role>
      <ShortName>Parent Company Financial Information- Condensed Statements of Financial Position (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>93</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R94.htm</HtmlFileName>
      <LongName>9955578 - Disclosure - Parent Company Financial Information- Condensed Statements of Financial Position- Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/ParentCompanyFinancialInformationCondensedStatementsofFinancialPositionAdditionalInformationDetails</Role>
      <ShortName>Parent Company Financial Information- Condensed Statements of Financial Position- Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>94</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R95.htm</HtmlFileName>
      <LongName>9955579 - Disclosure - Parent Company Financial Information- Condensed Statements of Cash Flows (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/ParentCompanyFinancialInformationCondensedStatementsofCashFlowsDetails</Role>
      <ShortName>Parent Company Financial Information- Condensed Statements of Cash Flows (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>95</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R96.htm</HtmlFileName>
      <LongName>9955580 - Disclosure - Segment Reporting - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/SegmentReportingNarrativeDetails</Role>
      <ShortName>Segment Reporting - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>96</Position>
    </Report>
    <Report instance="syf-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R97.htm</HtmlFileName>
      <LongName>9955581 - Disclosure - Segment Reporting - Schedule of Segment Reporting Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.synchronyfinancial.com/role/SegmentReportingScheduleofSegmentReportingInformationDetails</Role>
      <ShortName>Segment Reporting - Schedule of Segment Reporting Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>97</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="10-K" isDefinitelyFs="true" isUsgaap="true" original="syf-20251231.htm">syf-20251231.htm</File>
    <File>syf-20251231.xsd</File>
    <File>syf-20251231_cal.xml</File>
    <File>syf-20251231_def.xml</File>
    <File>syf-20251231_lab.xml</File>
    <File>syf-20251231_pre.xml</File>
  </InputFiles>
  <SupplementalFiles>
    <File>syf-20251231_g1.jpg</File>
    <File>syf-20251231_g10.jpg</File>
    <File>syf-20251231_g11.jpg</File>
    <File>syf-20251231_g12.jpg</File>
    <File>syf-20251231_g13.jpg</File>
    <File>syf-20251231_g14.jpg</File>
    <File>syf-20251231_g15.jpg</File>
    <File>syf-20251231_g16.jpg</File>
    <File>syf-20251231_g17.jpg</File>
    <File>syf-20251231_g18.jpg</File>
    <File>syf-20251231_g2.jpg</File>
    <File>syf-20251231_g3.jpg</File>
    <File>syf-20251231_g4.jpg</File>
    <File>syf-20251231_g5.jpg</File>
    <File>syf-20251231_g6.jpg</File>
    <File>syf-20251231_g7.jpg</File>
    <File>syf-20251231_g8.jpg</File>
    <File>syf-20251231_g9.jpg</File>
  </SupplementalFiles>
  <BaseTaxonomies>
    <BaseTaxonomy items="5">http://fasb.org/srt/2025</BaseTaxonomy>
    <BaseTaxonomy items="1696">http://fasb.org/us-gaap/2025</BaseTaxonomy>
    <BaseTaxonomy items="15">http://xbrl.sec.gov/cyd/2025</BaseTaxonomy>
    <BaseTaxonomy items="44">http://xbrl.sec.gov/dei/2025</BaseTaxonomy>
    <BaseTaxonomy items="55">http://xbrl.sec.gov/ecd/2025</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
