<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.24.3</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>1046</ContextCount>
  <ElementCount>409</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>false</FootnotesReported>
  <SegmentCount>133</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>7</UnitCount>
  <MyReports>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>0000001 - Document - DOCUMENT AND ENTITY INFORMATION</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/DOCUMENTANDENTITYINFORMATION</Role>
      <ShortName>DOCUMENT AND ENTITY INFORMATION</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>9952151 - Statement - CONSOLIDATED BALANCE SHEETS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/CONSOLIDATEDBALANCESHEETS</Role>
      <ShortName>CONSOLIDATED BALANCE SHEETS</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>9952152 - Statement - CONSOLIDATED BALANCE SHEETS (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/CONSOLIDATEDBALANCESHEETSParenthetical</Role>
      <ShortName>CONSOLIDATED BALANCE SHEETS (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>9952153 - Statement - CONSOLIDATED STATEMENTS OF INCOME</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/CONSOLIDATEDSTATEMENTSOFINCOME</Role>
      <ShortName>CONSOLIDATED STATEMENTS OF INCOME</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>9952154 - Statement - CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/CONSOLIDATEDSTATEMENTSOFCOMPREHENSIVEINCOME</Role>
      <ShortName>CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>9952155 - Statement - CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/CONSOLIDATEDSTATEMENTSOFCOMPREHENSIVEINCOMEParenthetical</Role>
      <ShortName>CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>9952156 - Statement - CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/CONSOLIDATEDSTATEMENTSOFCHANGESINSTOCKHOLDERSEQUITY</Role>
      <ShortName>CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>9952157 - Statement - CONSOLIDATED STATEMENTS OF CASH FLOWS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/CONSOLIDATEDSTATEMENTSOFCASHFLOWS</Role>
      <ShortName>CONSOLIDATED STATEMENTS OF CASH FLOWS</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>9952158 - Disclosure - Basis Of Presentation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/BasisOfPresentation</Role>
      <ShortName>Basis Of Presentation</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>9952159 - Disclosure - Variable Interest Entities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/VariableInterestEntities</Role>
      <ShortName>Variable Interest Entities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>9952160 - Disclosure - Debt Securities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/DebtSecurities</Role>
      <ShortName>Debt Securities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>9952161 - Disclosure - Loans And The Allowance For Credit Losses</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/LoansAndTheAllowanceForCreditLosses</Role>
      <ShortName>Loans And The Allowance For Credit Losses</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>9952162 - Disclosure - Servicing of Financial Assets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/ServicingofFinancialAssets</Role>
      <ShortName>Servicing of Financial Assets</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>9952163 - Disclosure - Stockholders' Equity and Accumulated Other Comprehensive Income (Loss)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/StockholdersEquityandAccumulatedOtherComprehensiveIncomeLoss</Role>
      <ShortName>Stockholders' Equity and Accumulated Other Comprehensive Income (Loss)</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>9952164 - Disclosure - Earnings Per Common Share</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/EarningsPerCommonShare</Role>
      <ShortName>Earnings Per Common Share</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>9952165 - Disclosure - Pension and Other Postretirement Benefits</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/PensionandOtherPostretirementBenefits</Role>
      <ShortName>Pension and Other Postretirement Benefits</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>9952166 - Disclosure - Derivative Financial Instruments and Hedging Activities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/DerivativeFinancialInstrumentsandHedgingActivities</Role>
      <ShortName>Derivative Financial Instruments and Hedging Activities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>9952167 - Disclosure - Fair Value Measurements</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/FairValueMeasurements</Role>
      <ShortName>Fair Value Measurements</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>9952168 - Disclosure - Business Segment Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/BusinessSegmentInformation</Role>
      <ShortName>Business Segment Information</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>9952169 - Disclosure - Commitments, Contingencies and Guarantees</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/CommitmentsContingenciesandGuarantees</Role>
      <ShortName>Commitments, Contingencies and Guarantees</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>9952170 - Disclosure - Recent Accounting Pronouncements</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/RecentAccountingPronouncements</Role>
      <ShortName>Recent Accounting Pronouncements</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>21</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>9954471 - Disclosure - Basis Of Presentation (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/BasisOfPresentationPolicies</Role>
      <ShortName>Basis Of Presentation (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <ParentRole>http://www.regions.com/role/RecentAccountingPronouncements</ParentRole>
      <Position>22</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>9954472 - Disclosure - Accounting Changes and Error Corrections (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/AccountingChangesandErrorCorrectionsPolicies</Role>
      <ShortName>Accounting Changes and Error Corrections (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <ParentRole>http://www.regions.com/role/RecentAccountingPronouncements</ParentRole>
      <Position>23</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>9954473 - Disclosure - Variable Interest Entities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/VariableInterestEntitiesTables</Role>
      <ShortName>Variable Interest Entities (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.regions.com/role/VariableInterestEntities</ParentRole>
      <Position>24</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>9954474 - Disclosure - Debt Securities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/DebtSecuritiesTables</Role>
      <ShortName>Debt Securities (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.regions.com/role/DebtSecurities</ParentRole>
      <Position>25</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>9954475 - Disclosure - Loans And The Allowance For Credit Losses (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/LoansAndTheAllowanceForCreditLossesTables</Role>
      <ShortName>Loans And The Allowance For Credit Losses (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.regions.com/role/LoansAndTheAllowanceForCreditLosses</ParentRole>
      <Position>26</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>9954476 - Disclosure - Servicing of Financial Assets (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/ServicingofFinancialAssetsTables</Role>
      <ShortName>Servicing of Financial Assets (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.regions.com/role/ServicingofFinancialAssets</ParentRole>
      <Position>27</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>9954477 - Disclosure - Stockholders' Equity and Accumulated Other Comprehensive Income (Loss) (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/StockholdersEquityandAccumulatedOtherComprehensiveIncomeLossTables</Role>
      <ShortName>Stockholders' Equity and Accumulated Other Comprehensive Income (Loss) (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.regions.com/role/StockholdersEquityandAccumulatedOtherComprehensiveIncomeLoss</ParentRole>
      <Position>28</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>9954478 - Disclosure - Earnings Per Common Share (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/EarningsPerCommonShareTables</Role>
      <ShortName>Earnings Per Common Share (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.regions.com/role/EarningsPerCommonShare</ParentRole>
      <Position>29</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>9954479 - Disclosure - Pension and Other Postretirement Benefits (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/PensionandOtherPostretirementBenefitsTables</Role>
      <ShortName>Pension and Other Postretirement Benefits (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.regions.com/role/PensionandOtherPostretirementBenefits</ParentRole>
      <Position>30</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>9954480 - Disclosure - Derivative Financial Instruments and Hedging Activities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/DerivativeFinancialInstrumentsandHedgingActivitiesTables</Role>
      <ShortName>Derivative Financial Instruments and Hedging Activities (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.regions.com/role/DerivativeFinancialInstrumentsandHedgingActivities</ParentRole>
      <Position>31</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>9954481 - Disclosure - Fair Value Measurements (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/FairValueMeasurementsTables</Role>
      <ShortName>Fair Value Measurements (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.regions.com/role/FairValueMeasurements</ParentRole>
      <Position>32</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>9954482 - Disclosure - Business Segment Information (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/BusinessSegmentInformationTables</Role>
      <ShortName>Business Segment Information (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.regions.com/role/BusinessSegmentInformation</ParentRole>
      <Position>33</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>9954483 - Disclosure - Commitments, Contingencies and Guarantees (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/CommitmentsContingenciesandGuaranteesTables</Role>
      <ShortName>Commitments, Contingencies and Guarantees (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.regions.com/role/CommitmentsContingenciesandGuarantees</ParentRole>
      <Position>34</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>9954484 - Disclosure - Variable Interest Entities Affordable Housing Tax Credit Investments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/VariableInterestEntitiesAffordableHousingTaxCreditInvestmentsDetails</Role>
      <ShortName>Variable Interest Entities Affordable Housing Tax Credit Investments (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>35</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>9954485 - Disclosure - Debt Securities (Schedule Of Amortized Cost, Gross Unrealized Gains And Losses, And Estimated Fair Value Of Securities Available For Sale And Securities Held To Maturity) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/DebtSecuritiesScheduleOfAmortizedCostGrossUnrealizedGainsAndLossesAndEstimatedFairValueOfSecuritiesAvailableForSaleAndSecuritiesHeldToMaturityDetails</Role>
      <ShortName>Debt Securities (Schedule Of Amortized Cost, Gross Unrealized Gains And Losses, And Estimated Fair Value Of Securities Available For Sale And Securities Held To Maturity) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.regions.com/role/DebtSecuritiesTables</ParentRole>
      <Position>36</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>9954486 - Disclosure - Debt Securities (Schedule Of Cost And Estimated Fair Value Of Securities Available For Sale And Securities Held To Maturity By Contractual Maturity) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/DebtSecuritiesScheduleOfCostAndEstimatedFairValueOfSecuritiesAvailableForSaleAndSecuritiesHeldToMaturityByContractualMaturityDetails</Role>
      <ShortName>Debt Securities (Schedule Of Cost And Estimated Fair Value Of Securities Available For Sale And Securities Held To Maturity By Contractual Maturity) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.regions.com/role/DebtSecuritiesTables</ParentRole>
      <Position>37</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>9954487 - Disclosure - Debt Securities (Schedule Of Gross Unrealized Losses And Estimated Fair Value Of Securities Available For Sale) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/DebtSecuritiesScheduleOfGrossUnrealizedLossesAndEstimatedFairValueOfSecuritiesAvailableForSaleDetails</Role>
      <ShortName>Debt Securities (Schedule Of Gross Unrealized Losses And Estimated Fair Value Of Securities Available For Sale) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.regions.com/role/DebtSecuritiesTables</ParentRole>
      <Position>38</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>9954488 - Disclosure - Debt Securities (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/DebtSecuritiesNarrativeDetails</Role>
      <ShortName>Debt Securities (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.regions.com/role/DebtSecuritiesTables</ParentRole>
      <Position>39</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>9954489 - Disclosure - Loans And The Allowance For Credit Losses (Loans by Segment) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/LoansAndTheAllowanceForCreditLossesLoansbySegmentDetails</Role>
      <ShortName>Loans And The Allowance For Credit Losses (Loans by Segment) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.regions.com/role/LoansAndTheAllowanceForCreditLossesTables</ParentRole>
      <Position>40</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>9954490 - Disclosure - Loans And The Allowance For Credit Losses (Analysis Of The Allowance For Credit Losses By Portfolio Segment) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/LoansAndTheAllowanceForCreditLossesAnalysisOfTheAllowanceForCreditLossesByPortfolioSegmentDetails</Role>
      <ShortName>Loans And The Allowance For Credit Losses (Analysis Of The Allowance For Credit Losses By Portfolio Segment) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.regions.com/role/LoansAndTheAllowanceForCreditLossesTables</ParentRole>
      <Position>41</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>9954491 - Disclosure - Loans And The Allowance For Credit Losses (Financing Receivables Credit Quality Indicators) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/LoansAndTheAllowanceForCreditLossesFinancingReceivablesCreditQualityIndicatorsDetails</Role>
      <ShortName>Loans And The Allowance For Credit Losses (Financing Receivables Credit Quality Indicators) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.regions.com/role/LoansAndTheAllowanceForCreditLossesTables</ParentRole>
      <Position>42</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>9954492 - Disclosure - Loans And The Allowance For Credit Losses (Past Due Financing Receivables) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/LoansAndTheAllowanceForCreditLossesPastDueFinancingReceivablesDetails</Role>
      <ShortName>Loans And The Allowance For Credit Losses (Past Due Financing Receivables) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.regions.com/role/LoansAndTheAllowanceForCreditLossesTables</ParentRole>
      <Position>43</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>9954493 - Disclosure - Loans And The Allowance For Credit Losses (Modifications By Class And Segment) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/LoansAndTheAllowanceForCreditLossesModificationsByClassAndSegmentDetails</Role>
      <ShortName>Loans And The Allowance For Credit Losses (Modifications By Class And Segment) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.regions.com/role/LoansAndTheAllowanceForCreditLossesTables</ParentRole>
      <Position>44</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>9954494 - Disclosure - Loans And The Allowance For Credit Losses (Financial Impact Of Modifications To Troubled Borrowers) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/LoansAndTheAllowanceForCreditLossesFinancialImpactOfModificationsToTroubledBorrowersDetails</Role>
      <ShortName>Loans And The Allowance For Credit Losses (Financial Impact Of Modifications To Troubled Borrowers) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.regions.com/role/LoansAndTheAllowanceForCreditLossesTables</ParentRole>
      <Position>45</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>9954495 - Disclosure - Loans And The Allowance For Credit Losses(Aging and Non-Accrual Performance for Modifications to Troubled Borrowers (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/LoansAndTheAllowanceForCreditLossesAgingandNonAccrualPerformanceforModificationstoTroubledBorrowersDetails</Role>
      <ShortName>Loans And The Allowance For Credit Losses(Aging and Non-Accrual Performance for Modifications to Troubled Borrowers (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>46</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>9954496 - Disclosure - Loans And The Allowance For Credit Losses (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/LoansAndTheAllowanceForCreditLossesNarrativeDetails</Role>
      <ShortName>Loans And The Allowance For Credit Losses (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.regions.com/role/LoansAndTheAllowanceForCreditLossesTables</ParentRole>
      <Position>47</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>9954497 - Disclosure - Servicing of Financial Assets (Analysis Of Residential MSRs Under The Fair Value Measurement Method) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/ServicingofFinancialAssetsAnalysisOfResidentialMSRsUnderTheFairValueMeasurementMethodDetails</Role>
      <ShortName>Servicing of Financial Assets (Analysis Of Residential MSRs Under The Fair Value Measurement Method) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.regions.com/role/ServicingofFinancialAssetsTables</ParentRole>
      <Position>48</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>9954498 - Disclosure - Servicing of Financial Assets (Data And Assumptions Used In The Fair Value Calculation As Well As The Valuation's Sensitivity To Rate Fluctuations Related To Mortgage Servicing Rights) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/ServicingofFinancialAssetsDataAndAssumptionsUsedInTheFairValueCalculationAsWellAsTheValuationsSensitivityToRateFluctuationsRelatedToMortgageServicingRightsDetails</Role>
      <ShortName>Servicing of Financial Assets (Data And Assumptions Used In The Fair Value Calculation As Well As The Valuation's Sensitivity To Rate Fluctuations Related To Mortgage Servicing Rights) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.regions.com/role/ServicingofFinancialAssetsTables</ParentRole>
      <Position>49</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>9954499 - Disclosure - Servicing of Financial Assets (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/ServicingofFinancialAssetsNarrativeDetails</Role>
      <ShortName>Servicing of Financial Assets (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.regions.com/role/ServicingofFinancialAssetsTables</ParentRole>
      <Position>50</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>9954500 - Disclosure - Stockholders' Equity and Accumulated Other Comprehensive Income (Loss) (Preferred Stock Issuances) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/StockholdersEquityandAccumulatedOtherComprehensiveIncomeLossPreferredStockIssuancesDetails</Role>
      <ShortName>Stockholders' Equity and Accumulated Other Comprehensive Income (Loss) (Preferred Stock Issuances) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.regions.com/role/StockholdersEquityandAccumulatedOtherComprehensiveIncomeLossTables</ParentRole>
      <Position>51</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>9954501 - Disclosure - Stockholders' Equity and Accumulated Other Comprehensive Income (Loss)(Schedule of Accumulated Other Comprehensive Income) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/StockholdersEquityandAccumulatedOtherComprehensiveIncomeLossScheduleofAccumulatedOtherComprehensiveIncomeDetails</Role>
      <ShortName>Stockholders' Equity and Accumulated Other Comprehensive Income (Loss)(Schedule of Accumulated Other Comprehensive Income) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.regions.com/role/StockholdersEquityandAccumulatedOtherComprehensiveIncomeLossTables</ParentRole>
      <Position>52</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>9954502 - Disclosure - Stockholders' Equity And Accumulated Other Comprehensive Income (Loss) (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/StockholdersEquityAndAccumulatedOtherComprehensiveIncomeLossNarrativeDetails</Role>
      <ShortName>Stockholders' Equity And Accumulated Other Comprehensive Income (Loss) (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>53</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>9954503 - Disclosure - Earnings Per Common Share (Computation Of Basic And Diluted Earnings (Loss) Per Common Share) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/EarningsPerCommonShareComputationOfBasicAndDilutedEarningsLossPerCommonShareDetails</Role>
      <ShortName>Earnings Per Common Share (Computation Of Basic And Diluted Earnings (Loss) Per Common Share) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.regions.com/role/EarningsPerCommonShareTables</ParentRole>
      <Position>54</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>9954504 - Disclosure - Pension and Other Postretirement Benefits (Schedule of Net Periodic Pension Cost) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/PensionandOtherPostretirementBenefitsScheduleofNetPeriodicPensionCostDetails</Role>
      <ShortName>Pension and Other Postretirement Benefits (Schedule of Net Periodic Pension Cost) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.regions.com/role/PensionandOtherPostretirementBenefitsTables</ParentRole>
      <Position>55</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>9954505 - Disclosure - Derivative Financial Instruments And Hedging Activities (Schedule Of Derivative Instruments Notional And Fair Values) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/DerivativeFinancialInstrumentsAndHedgingActivitiesScheduleOfDerivativeInstrumentsNotionalAndFairValuesDetails</Role>
      <ShortName>Derivative Financial Instruments And Hedging Activities (Schedule Of Derivative Instruments Notional And Fair Values) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>56</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>9954506 - Disclosure - Derivative Financial Instruments And Hedging Activities (Schedule Of The Effect Of Derivative Instruments On The Statements Of Operations) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/DerivativeFinancialInstrumentsAndHedgingActivitiesScheduleOfTheEffectOfDerivativeInstrumentsOnTheStatementsOfOperationsDetails</Role>
      <ShortName>Derivative Financial Instruments And Hedging Activities (Schedule Of The Effect Of Derivative Instruments On The Statements Of Operations) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>57</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R58.htm</HtmlFileName>
      <LongName>9954507 - Disclosure - Derivative Financial Instruments and Hedging Activities Derivative Financial Instruments and Hedging Activities (Schedule of Fair Value Hedging Basis Adjustments) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/DerivativeFinancialInstrumentsandHedgingActivitiesDerivativeFinancialInstrumentsandHedgingActivitiesScheduleofFairValueHedgingBasisAdjustmentsDetails</Role>
      <ShortName>Derivative Financial Instruments and Hedging Activities Derivative Financial Instruments and Hedging Activities (Schedule of Fair Value Hedging Basis Adjustments) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>58</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R59.htm</HtmlFileName>
      <LongName>9954508 - Disclosure - Derivative Financial Instruments And Hedging Activities (Schedule Of Gains (Losses) Recognized Related To Derivatives Not Designated As Hedging Instruments) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/DerivativeFinancialInstrumentsAndHedgingActivitiesScheduleOfGainsLossesRecognizedRelatedToDerivativesNotDesignatedAsHedgingInstrumentsDetails</Role>
      <ShortName>Derivative Financial Instruments And Hedging Activities (Schedule Of Gains (Losses) Recognized Related To Derivatives Not Designated As Hedging Instruments) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>59</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R60.htm</HtmlFileName>
      <LongName>9954509 - Disclosure - Derivative Financial Instruments And Hedging Activities (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/DerivativeFinancialInstrumentsAndHedgingActivitiesNarrativeDetails</Role>
      <ShortName>Derivative Financial Instruments And Hedging Activities (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>60</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R61.htm</HtmlFileName>
      <LongName>9954510 - Disclosure - Fair Value Measurements (Schedule Of Assets And Liabilities At Fair Value Measured On A Recurring Basis) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/FairValueMeasurementsScheduleOfAssetsAndLiabilitiesAtFairValueMeasuredOnARecurringBasisDetails</Role>
      <ShortName>Fair Value Measurements (Schedule Of Assets And Liabilities At Fair Value Measured On A Recurring Basis) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.regions.com/role/FairValueMeasurementsTables</ParentRole>
      <Position>61</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R62.htm</HtmlFileName>
      <LongName>9954511 - Disclosure - Fair Value Measurements (Summary Of Quantitative Information About Level 3 Fair Value Measurements) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/FairValueMeasurementsSummaryOfQuantitativeInformationAboutLevel3FairValueMeasurementsDetails</Role>
      <ShortName>Fair Value Measurements (Summary Of Quantitative Information About Level 3 Fair Value Measurements) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.regions.com/role/FairValueMeasurementsTables</ParentRole>
      <Position>62</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R63.htm</HtmlFileName>
      <LongName>9954512 - Disclosure - Fair Value Measurements (Fair Value Option, Fair Value and Unpaid Principal Balance) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/FairValueMeasurementsFairValueOptionFairValueandUnpaidPrincipalBalanceDetails</Role>
      <ShortName>Fair Value Measurements (Fair Value Option, Fair Value and Unpaid Principal Balance) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.regions.com/role/FairValueMeasurementsTables</ParentRole>
      <Position>63</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R64.htm</HtmlFileName>
      <LongName>9954513 - Disclosure - Fair Value Measurements (Schedule Of Carrying Amounts And Estimated Fair Values Of Financial Instruments) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/FairValueMeasurementsScheduleOfCarryingAmountsAndEstimatedFairValuesOfFinancialInstrumentsDetails</Role>
      <ShortName>Fair Value Measurements (Schedule Of Carrying Amounts And Estimated Fair Values Of Financial Instruments) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.regions.com/role/FairValueMeasurementsTables</ParentRole>
      <Position>64</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R65.htm</HtmlFileName>
      <LongName>9954514 - Disclosure - Business Segment Information (Schedule Of Financial Information By Reportable Segment) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/BusinessSegmentInformationScheduleOfFinancialInformationByReportableSegmentDetails</Role>
      <ShortName>Business Segment Information (Schedule Of Financial Information By Reportable Segment) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.regions.com/role/BusinessSegmentInformationTables</ParentRole>
      <Position>65</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R66.htm</HtmlFileName>
      <LongName>9954515 - Disclosure - Commitments, Contingencies and Guarantees (Credit Risk Of Financial Instruments By Contractual Amounts) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/CommitmentsContingenciesandGuaranteesCreditRiskOfFinancialInstrumentsByContractualAmountsDetails</Role>
      <ShortName>Commitments, Contingencies and Guarantees (Credit Risk Of Financial Instruments By Contractual Amounts) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.regions.com/role/CommitmentsContingenciesandGuaranteesTables</ParentRole>
      <Position>66</Position>
    </Report>
    <Report instance="rf-20240930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R67.htm</HtmlFileName>
      <LongName>9954516 - Disclosure - Commitments, Contingencies and Guarantees (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.regions.com/role/CommitmentsContingenciesandGuaranteesNarrativeDetails</Role>
      <ShortName>Commitments, Contingencies and Guarantees (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.regions.com/role/CommitmentsContingenciesandGuaranteesTables</ParentRole>
      <Position>67</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-Q" isDefinitelyFs="true" isUsgaap="true" original="rf-20240930.htm">rf-20240930.htm</File>
    <File>rf-20240930.xsd</File>
    <File>rf-20240930_cal.xml</File>
    <File>rf-20240930_def.xml</File>
    <File>rf-20240930_lab.xml</File>
    <File>rf-20240930_pre.xml</File>
  </InputFiles>
  <SupplementalFiles/>
  <BaseTaxonomies>
    <BaseTaxonomy items="1">http://fasb.org/srt/2024</BaseTaxonomy>
    <BaseTaxonomy items="3974">http://fasb.org/us-gaap/2024</BaseTaxonomy>
    <BaseTaxonomy items="38">http://xbrl.sec.gov/dei/2024</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
