<?xml version="1.0" encoding="utf-8"?>
<FilingSummary xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <Version>2.4.0.6</Version>
  <ProcessingTime />
  <ReportFormat>Html</ReportFormat>
  <ContextCount>1186</ContextCount>
  <ElementCount>819</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>true</FootnotesReported>
  <SegmentCount>228</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>15</UnitCount>
  <MyReports>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>1001 - Document - Document and Entity Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DocumentDocumentandEntityInformation</Role>
      <ShortName>Document and Entity Information</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>1003 - Statement - Consolidated Statements Of Income</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/StatementOfIncomeAlternative</Role>
      <ShortName>Consolidated Statements Of Income</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>1004 - Statement - Consolidated Statements Of Comprehensive Income</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/StatementOfOtherComprehensiveIncome</Role>
      <ShortName>Consolidated Statements Of Comprehensive Income</ShortName>
    </Report>
    <Report>
      <IsDefault>true</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>1005 - Statement - Consolidated Balance Sheets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/StatementOfFinancialPositionClassified</Role>
      <ShortName>Consolidated Balance Sheets</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>1006 - Statement - Consolidated Balance Sheets (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/StatementOfFinancialPositionClassifiedParenthetical</Role>
      <ShortName>Consolidated Balance Sheets (Parenthetical)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>1007 - Statement - Consolidated Statements Of Cash Flows</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/StatementOfCashFlowsIndirect</Role>
      <ShortName>Consolidated Statements Of Cash Flows</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>1008 - Statement - Consolidated Statements Of Cash Flows (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/StatementOfCashFlowsIndirectParenthetical</Role>
      <ShortName>Consolidated Statements Of Cash Flows (Parenthetical)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>1009 - Statement - Consolidated Statements Of Equity</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/StatementOfShareholdersEquityAndOtherComprehensiveIncome</Role>
      <ShortName>Consolidated Statements Of Equity</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>1010 - Statement - Consolidated Statements Of Equity (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/StatementOfShareholdersEquityAndOtherComprehensiveIncomeParenthetical</Role>
      <ShortName>Consolidated Statements Of Equity (Parenthetical)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>1011 - Disclosure - ORGANIZATION</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/NotesToFinancialStatementsOrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlock</Role>
      <ShortName>ORGANIZATION</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>1012 - Disclosure - Significant Accounting Policies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/NotesToFinancialStatementsSignificantAccountingPoliciesTextBlock</Role>
      <ShortName>Significant Accounting Policies</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>1013 - Disclosure - Newly Adopted Accounting Standards</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/NotesToFinancialStatementsScheduleOfNewAccountingPronouncementsAndChangesInAccountingPrinciplesTextBlock</Role>
      <ShortName>Newly Adopted Accounting Standards</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>1014 - Disclosure - Recently Issued Accounting Standards, Not Yet Adopted</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/NotesToFinancialStatementsDescriptionOfNewAccountingPronouncementsNotYetAdopted</Role>
      <ShortName>Recently Issued Accounting Standards, Not Yet Adopted</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>1015 - Disclosure - Segment Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/NotesToFinancialStatementsSegmentReportingDisclosureTextBlock</Role>
      <ShortName>Segment Information</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>1016 - Disclosure - GOODWILL</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/NotesToFinancialStatementsGoodwillDisclosureTextBlock</Role>
      <ShortName>GOODWILL</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>1017 - Disclosure - Regulatory Matters</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/NotesToFinancialStatementsScheduleOfRegulatoryAssetsAndLiabilitiesTextBlock</Role>
      <ShortName>Regulatory Matters</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>1018 - Disclosure - Leasing Activities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/NotesToFinancialStatementsLeasesOfLessorDisclosureTextBlock</Role>
      <ShortName>Leasing Activities</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>1019 - Disclosure - Property, Plant And Equipment</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/NotesToFinancialStatementsPropertyPlantAndEquipmentDisclosureTextBlock</Role>
      <ShortName>Property, Plant And Equipment</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>1020 - Disclosure - Pension And Other Postretirement Benefits</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/NotesToFinancialStatementsPensionAndOtherPostretirementBenefitsDisclosureTextBlock</Role>
      <ShortName>Pension And Other Postretirement Benefits</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>1021 - Disclosure - Debt</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/NotesToFinancialStatementsDebtDisclosureTextBlock</Role>
      <ShortName>Debt</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>1022 - Disclosure - Income Taxes</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/NotesToFinancialStatementsIncomeTaxDisclosureTextBlock</Role>
      <ShortName>Income Taxes</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>1023 - Disclosure - Stock-Based Compensation, Dividend Restrictions, And Calculations Of Earnings Per Share Of Common Stock</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock</Role>
      <ShortName>Stock-Based Compensation, Dividend Restrictions, And Calculations Of Earnings Per Share Of Common Stock</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>1024 - Disclosure - Derivative Instruments And Hedging Activities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/NotesToFinancialStatementsDerivativeInstrumentsAndHedgingActivitiesDisclosureTextBlock</Role>
      <ShortName>Derivative Instruments And Hedging Activities</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>1025 - Disclosure - Fair Value Disclosures</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/NotesToFinancialStatementsFairValueDisclosuresTextBlock</Role>
      <ShortName>Fair Value Disclosures</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>1026 - Disclosure - Commitments And Contingencies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/NotesToFinancialStatementsCommitmentsAndContingenciesDisclosureTextBlock</Role>
      <ShortName>Commitments And Contingencies</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>1027 - Disclosure - ACCUMULATED OTHER COMPREHENSIVE LOSS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/NotesToFinancialStatementsComprehensiveIncomeNoteTextBlock</Role>
      <ShortName>ACCUMULATED OTHER COMPREHENSIVE LOSS</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>1028 - Disclosure - Quarterly Financial Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/NotesToFinancialStatementsQuarterlyFinancialInformationTextBlock</Role>
      <ShortName>Quarterly Financial Information</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>1029 - Disclosure - Discontinued Operations</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/NotesToFinancialStatementsDisposalGroupsIncludingDiscontinuedOperationsDisclosureTextBlock</Role>
      <ShortName>Discontinued Operations</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>1030 - Disclosure - Subsequent Event</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/NotesToFinancialStatementsSubsequentEventTextBlock</Role>
      <ShortName>Subsequent Event</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>1031 - Disclosure - Related Party Transactions</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/NotesToFinancialStatementsRelatedPartyTransactionsDisclosureTextBlock</Role>
      <ShortName>Related Party Transactions</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>1032 - Disclosure - Schedule I</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/NotesToFinancialStatementsCondensedFinancialInformationOfParentCompanyOnlyDisclosureTextBlock</Role>
      <ShortName>Schedule I</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>1033 - Disclosure - Schedule II</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/NotesToFinancialStatementsScheduleOfValuationAndQualifyingAccountsDisclosureTextBlock</Role>
      <ShortName>Schedule II</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>1034 - Disclosure - Significant Accounting Policies (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/NotesToFinancialStatementsSignificantAccountingPoliciesTextBlockPolicies</Role>
      <ShortName>Significant Accounting Policies (Policies)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>1035 - Disclosure - Significant Accounting Policies (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/NotesToFinancialStatementsSignificantAccountingPoliciesTextBlockTables</Role>
      <ShortName>Significant Accounting Policies (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>1036 - Disclosure - Segment Information (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/NotesToFinancialStatementsSegmentReportingDisclosureTextBlockTables</Role>
      <ShortName>Segment Information (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>1037 - Disclosure - GOODWILL (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/NotesToFinancialStatementsGoodwillDisclosureTextBlockTables</Role>
      <ShortName>GOODWILL (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>1038 - Disclosure - Regulatory Matters (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/NotesToFinancialStatementsScheduleOfRegulatoryAssetsAndLiabilitiesTextBlockTables</Role>
      <ShortName>Regulatory Matters (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>1039 - Disclosure - Leasing Activities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/NotesToFinancialStatementsLeasesOfLessorDisclosureTextBlockTables</Role>
      <ShortName>Leasing Activities (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>1040 - Disclosure - Property, Plant And Equipment (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/NotesToFinancialStatementsPropertyPlantAndEquipmentDisclosureTextBlockTables</Role>
      <ShortName>Property, Plant And Equipment (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>1041 - Disclosure - Pension And Other Postretirement Benefits (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/NotesToFinancialStatementsPensionAndOtherPostretirementBenefitsDisclosureTextBlockTables</Role>
      <ShortName>Pension And Other Postretirement Benefits (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>1042 - Disclosure - Debt (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/NotesToFinancialStatementsDebtDisclosureTextBlockTables</Role>
      <ShortName>Debt (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>1043 - Disclosure - Income Taxes (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/NotesToFinancialStatementsIncomeTaxDisclosureTextBlockTables</Role>
      <ShortName>Income Taxes (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>1044 - Disclosure - Stock-Based Compensation, Dividend Restrictions, And Calculations Of Earnings Per Share Of Common Stock (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/NotesToFinancialStatementsDisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlockTables</Role>
      <ShortName>Stock-Based Compensation, Dividend Restrictions, And Calculations Of Earnings Per Share Of Common Stock (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>1045 - Disclosure - Derivative Instruments And Hedging Activities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/NotesToFinancialStatementsDerivativeInstrumentsAndHedgingActivitiesDisclosureTextBlockTables</Role>
      <ShortName>Derivative Instruments And Hedging Activities (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>1046 - Disclosure - Fair Value Disclosures (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/NotesToFinancialStatementsFairValueDisclosuresTextBlockTables</Role>
      <ShortName>Fair Value Disclosures (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>1047 - Disclosure - Commitments And Contingencies (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/NotesToFinancialStatementsCommitmentsAndContingenciesDisclosureTextBlockTables</Role>
      <ShortName>Commitments And Contingencies (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>1048 - Disclosure - ACCUMULATED OTHER COMPREHENSIVE LOSS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/NotesToFinancialStatementsComprehensiveIncomeNoteTextBlockTables</Role>
      <ShortName>ACCUMULATED OTHER COMPREHENSIVE LOSS (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>1049 - Disclosure - Quarterly Financial Information (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/NotesToFinancialStatementsQuarterlyFinancialInformationTextBlockTables</Role>
      <ShortName>Quarterly Financial Information (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>1050 - Disclosure - Related Party Transactions (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/NotesToFinancialStatementsRelatedPartyTransactionsDisclosureTextBlockTables</Role>
      <ShortName>Related Party Transactions (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>1051 - Disclosure - Organization (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureOrganization</Role>
      <ShortName>Organization (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>1052 - Disclosure - Significant Accounting Policies (Narrative) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureSignificantAccountingPoliciesNarrative</Role>
      <ShortName>Significant Accounting Policies (Narrative) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>1053 - Disclosure - Significant Accounting Policies (Annual Depreciation Rates) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureSignificantAccountingPoliciesAnnualDepreciationRates</Role>
      <ShortName>Significant Accounting Policies (Annual Depreciation Rates) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>1054 - Disclosure - Segment Information (Segment Financial Information For Continuing Operations) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureSegmentInformationSegmentFinancialInformationForContinuingOperations</Role>
      <ShortName>Segment Information (Segment Financial Information For Continuing Operations) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>1055 - Disclosure - Goodwill (Narrative) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureGoodwillNarrative</Role>
      <ShortName>Goodwill (Narrative) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>1056 - Disclosure - Goodwill (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureGoodwill</Role>
      <ShortName>Goodwill (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>1057 - Disclosure - Regulatory Matters (Schedule Of Regulatory Assets And Regulatory Liabilities) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureRegulatoryMattersScheduleOfRegulatoryAssetsAndRegulatoryLiabilities</Role>
      <ShortName>Regulatory Matters (Schedule Of Regulatory Assets And Regulatory Liabilities) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>1058 - Disclosure - Regulatory Matters (Narrative) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureRegulatoryMattersNarrative</Role>
      <ShortName>Regulatory Matters (Narrative) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R58.htm</HtmlFileName>
      <LongName>1059 - Disclosure - Leasing Activities (Narrative) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureLeasingActivitiesNarrative</Role>
      <ShortName>Leasing Activities (Narrative) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R59.htm</HtmlFileName>
      <LongName>1060 - Disclosure - Leasing Activities (Cross-Border Energy Lease Investments) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureLeasingActivitiesCrossBorderEnergyLeaseInvestments</Role>
      <ShortName>Leasing Activities (Cross-Border Energy Lease Investments) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R60.htm</HtmlFileName>
      <LongName>1061 - Disclosure - Leasing Activities (Income Recognized From Cross-Border Energy Lease Investments) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureLeasingActivitiesIncomeRecognizedFromCrossBorderEnergyLeaseInvestments</Role>
      <ShortName>Leasing Activities (Income Recognized From Cross-Border Energy Lease Investments) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R61.htm</HtmlFileName>
      <LongName>1062 - Disclosure - Leasing Activities (Net Investment In Leases By Published Credit Ratings) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureLeasingActivitiesNetInvestmentInLeasesByPublishedCreditRatings</Role>
      <ShortName>Leasing Activities (Net Investment In Leases By Published Credit Ratings) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R62.htm</HtmlFileName>
      <LongName>1063 - Disclosure - Leasing Activities (Capital Lease Assets Recorded Within Property, Plant And Equipment) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureLeasingActivitiesCapitalLeaseAssetsRecordedWithinPropertyPlantAndEquipment</Role>
      <ShortName>Leasing Activities (Capital Lease Assets Recorded Within Property, Plant And Equipment) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R63.htm</HtmlFileName>
      <LongName>1064 - Disclosure - Property, Plant And Equipment (Schedule Of Property Plant And Equipment) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosurePropertyPlantAndEquipmentScheduleOfPropertyPlantAndEquipment</Role>
      <ShortName>Property, Plant And Equipment (Schedule Of Property Plant And Equipment) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R64.htm</HtmlFileName>
      <LongName>1065 - Disclosure - Property, Plant And Equipment (Narrative) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosurePropertyPlantAndEquipmentNarrative</Role>
      <ShortName>Property, Plant And Equipment (Narrative) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R65.htm</HtmlFileName>
      <LongName>1066 - Disclosure - Pension And Other Postretirement Benefits (Schedule Of Changes In Benefit Obligations And Plan Assets) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosurePensionAndOtherPostretirementBenefitsScheduleOfChangesInBenefitObligationsAndPlanAssets</Role>
      <ShortName>Pension And Other Postretirement Benefits (Schedule Of Changes In Benefit Obligations And Plan Assets) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R66.htm</HtmlFileName>
      <LongName>1067 - Disclosure - Pension And Other Postretirement Benefits (Narrative) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosurePensionAndOtherPostretirementBenefitsNarrative</Role>
      <ShortName>Pension And Other Postretirement Benefits (Narrative) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R67.htm</HtmlFileName>
      <LongName>1068 - Disclosure - Pension And Other Postretirement Benefits (Amounts Recognized In Consolidated Balance Sheets) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosurePensionAndOtherPostretirementBenefitsAmountsRecognizedInConsolidatedBalanceSheets</Role>
      <ShortName>Pension And Other Postretirement Benefits (Amounts Recognized In Consolidated Balance Sheets) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R68.htm</HtmlFileName>
      <LongName>1069 - Disclosure - Pension And Other Postretirement Benefits (Schedule Of Amounts Included In Aocl And Regulatory Assets) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosurePensionAndOtherPostretirementBenefitsScheduleOfAmountsIncludedInAoclAndRegulatoryAssets</Role>
      <ShortName>Pension And Other Postretirement Benefits (Schedule Of Amounts Included In Aocl And Regulatory Assets) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R69.htm</HtmlFileName>
      <LongName>1070 - Disclosure - Pension And Other Postretirement Benefits (Schedule Of Amounts Included In Aocl And Regulatory Assets) (Parenthetical) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosurePensionAndOtherPostretirementBenefitsScheduleOfAmountsIncludedInAoclAndRegulatoryAssetsParenthetical</Role>
      <ShortName>Pension And Other Postretirement Benefits (Schedule Of Amounts Included In Aocl And Regulatory Assets) (Parenthetical) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R70.htm</HtmlFileName>
      <LongName>1071 - Disclosure - Pension And Other Postretirement Benefits (Components Of Net Periodic Benefit Cost) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosurePensionAndOtherPostretirementBenefitsComponentsOfNetPeriodicBenefitCost</Role>
      <ShortName>Pension And Other Postretirement Benefits (Components Of Net Periodic Benefit Cost) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R71.htm</HtmlFileName>
      <LongName>1072 - Disclosure - Pension And Other Postretirement Benefits (Split Of Combined Pension And Other Postretirement Net Periodic Benefit Costs) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosurePensionAndOtherPostretirementBenefitsSplitOfCombinedPensionAndOtherPostretirementNetPeriodicBenefitCosts</Role>
      <ShortName>Pension And Other Postretirement Benefits (Split Of Combined Pension And Other Postretirement Net Periodic Benefit Costs) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R72.htm</HtmlFileName>
      <LongName>1073 - Disclosure - Pension And Other Postretirement Benefits (Weighted Average Assumptions Used To Determine Benefit Obligations) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosurePensionAndOtherPostretirementBenefitsWeightedAverageAssumptionsUsedToDetermineBenefitObligations</Role>
      <ShortName>Pension And Other Postretirement Benefits (Weighted Average Assumptions Used To Determine Benefit Obligations) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R73.htm</HtmlFileName>
      <LongName>1074 - Disclosure - Pension And Other Postretirement Benefits (Summary Of Effect Of One Percent Change In Assumed Health Care Cost) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosurePensionAndOtherPostretirementBenefitsSummaryOfEffectOfOnePercentChangeInAssumedHealthCareCost</Role>
      <ShortName>Pension And Other Postretirement Benefits (Summary Of Effect Of One Percent Change In Assumed Health Care Cost) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R74.htm</HtmlFileName>
      <LongName>1075 - Disclosure - Pension And Other Postretirement Benefits (Weighted Average Assumptions Used To Determine Net Periodic Benefit Costs) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosurePensionAndOtherPostretirementBenefitsWeightedAverageAssumptionsUsedToDetermineNetPeriodicBenefitCosts</Role>
      <ShortName>Pension And Other Postretirement Benefits (Weighted Average Assumptions Used To Determine Net Periodic Benefit Costs) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R75.htm</HtmlFileName>
      <LongName>1076 - Disclosure - Pension And Other Postretirement Benefits (Summary Of Plan Asset Allocations) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosurePensionAndOtherPostretirementBenefitsSummaryOfPlanAssetAllocations</Role>
      <ShortName>Pension And Other Postretirement Benefits (Summary Of Plan Asset Allocations) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R76.htm</HtmlFileName>
      <LongName>1077 - Disclosure - Pension And Other Postretirement Benefits (Schedule Of Fair Value Of Plan Assets) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosurePensionAndOtherPostretirementBenefitsScheduleOfFairValueOfPlanAssets</Role>
      <ShortName>Pension And Other Postretirement Benefits (Schedule Of Fair Value Of Plan Assets) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R77.htm</HtmlFileName>
      <LongName>1078 - Disclosure - Pension And Other Postretirement Benefits (Reconciliation Of Fair Value Measurements Using Significant Unobservable Inputs) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosurePensionAndOtherPostretirementBenefitsReconciliationOfFairValueMeasurementsUsingSignificantUnobservableInputs</Role>
      <ShortName>Pension And Other Postretirement Benefits (Reconciliation Of Fair Value Measurements Using Significant Unobservable Inputs) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R78.htm</HtmlFileName>
      <LongName>1079 - Disclosure - Pension And Other Postretirement Benefits (Schedule Of Estimated Benefit Payments) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosurePensionAndOtherPostretirementBenefitsScheduleOfEstimatedBenefitPayments</Role>
      <ShortName>Pension And Other Postretirement Benefits (Schedule Of Estimated Benefit Payments) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R79.htm</HtmlFileName>
      <LongName>1080 - Disclosure - Debt (Components Of Long-Term Debt) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureDebtComponentsOfLongTermDebt</Role>
      <ShortName>Debt (Components Of Long-Term Debt) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R80.htm</HtmlFileName>
      <LongName>1081 - Disclosure - Debt (Components Of Long-Term Debt) (Parenthetical) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureDebtComponentsOfLongTermDebtParenthetical</Role>
      <ShortName>Debt (Components Of Long-Term Debt) (Parenthetical) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R81.htm</HtmlFileName>
      <LongName>1082 - Disclosure - Debt (Narrative) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureDebtNarrative</Role>
      <ShortName>Debt (Narrative) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R82.htm</HtmlFileName>
      <LongName>1083 - Disclosure - Debt (Components Of Short-Term Debt) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureDebtComponentsOfShortTermDebt</Role>
      <ShortName>Debt (Components Of Short-Term Debt) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R83.htm</HtmlFileName>
      <LongName>1084 - Disclosure - Income Taxes (Schedule Of Income Tax Expense (Benefit)) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureIncomeTaxesScheduleOfIncomeTaxExpenseBenefit</Role>
      <ShortName>Income Taxes (Schedule Of Income Tax Expense (Benefit)) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R84.htm</HtmlFileName>
      <LongName>1085 - Disclosure - Income Taxes (Reconciliation Of Effective Income Tax Rate From Continuing Operations) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureIncomeTaxesReconciliationOfEffectiveIncomeTaxRateFromContinuingOperations</Role>
      <ShortName>Income Taxes (Reconciliation Of Effective Income Tax Rate From Continuing Operations) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R85.htm</HtmlFileName>
      <LongName>1086 - Disclosure - Income Taxes (Narrative) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureIncomeTaxesNarrative</Role>
      <ShortName>Income Taxes (Narrative) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R86.htm</HtmlFileName>
      <LongName>1087 - Disclosure - Income Taxes (Components Of Consolidated Deferred Tax Liabilities (Assets)) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureIncomeTaxesComponentsOfConsolidatedDeferredTaxLiabilitiesAssets</Role>
      <ShortName>Income Taxes (Components Of Consolidated Deferred Tax Liabilities (Assets)) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R87.htm</HtmlFileName>
      <LongName>1088 - Disclosure - Income Taxes (Reconciliation Of Beginning And Ending Balances Of Unrecognized Tax Benefits) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureIncomeTaxesReconciliationOfBeginningAndEndingBalancesOfUnrecognizedTaxBenefits</Role>
      <ShortName>Income Taxes (Reconciliation Of Beginning And Ending Balances Of Unrecognized Tax Benefits) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R88.htm</HtmlFileName>
      <LongName>1089 - Disclosure - Income Taxes (Other Taxes) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureIncomeTaxesOtherTaxes</Role>
      <ShortName>Income Taxes (Other Taxes) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R89.htm</HtmlFileName>
      <LongName>1090 - Disclosure - Stock-Based Compensation, Dividend Restrictions, And Calculations Of Earnings Per Share Of Common Stock (Narrative) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureStockBasedCompensationDividendRestrictionsAndCalculationsOfEarningsPerShareOfCommonStockNarrative</Role>
      <ShortName>Stock-Based Compensation, Dividend Restrictions, And Calculations Of Earnings Per Share Of Common Stock (Narrative) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R90.htm</HtmlFileName>
      <LongName>1091 - Disclosure - Stock-Based Compensation, Dividend Restrictions, And Calculations Of Earnings Per Share Of Common Stock (Schedule Of Restricted Stock And Restricted Stock Units) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureStockBasedCompensationDividendRestrictionsAndCalculationsOfEarningsPerShareOfCommonStockScheduleOfRestrictedStockAndRestrictedStockUnits</Role>
      <ShortName>Stock-Based Compensation, Dividend Restrictions, And Calculations Of Earnings Per Share Of Common Stock (Schedule Of Restricted Stock And Restricted Stock Units) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R91.htm</HtmlFileName>
      <LongName>1092 - Disclosure - Stock-Based Compensation, Dividend Restrictions, And Calculations Of Earnings Per Share Of Common Stock (Weighted Average Grant Date Fair Value) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureStockBasedCompensationDividendRestrictionsAndCalculationsOfEarningsPerShareOfCommonStockWeightedAverageGrantDateFairValue</Role>
      <ShortName>Stock-Based Compensation, Dividend Restrictions, And Calculations Of Earnings Per Share Of Common Stock (Weighted Average Grant Date Fair Value) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R92.htm</HtmlFileName>
      <LongName>1093 - Disclosure - Stock-Based Compensation, Dividend Restrictions, And Calculations Of Earnings Per Share Of Common Stock (Dividends Received From Subsidiaries) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureStockBasedCompensationDividendRestrictionsAndCalculationsOfEarningsPerShareOfCommonStockDividendsReceivedFromSubsidiaries</Role>
      <ShortName>Stock-Based Compensation, Dividend Restrictions, And Calculations Of Earnings Per Share Of Common Stock (Dividends Received From Subsidiaries) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R93.htm</HtmlFileName>
      <LongName>1094 - Disclosure - Stock-Based Compensation, Dividend Restrictions, And Calculations Of Earnings Per Share Of Common Stock (Calculations Of Earnings Per Share Of Common Stock) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureStockBasedCompensationDividendRestrictionsAndCalculationsOfEarningsPerShareOfCommonStockCalculationsOfEarningsPerShareOfCommonStock</Role>
      <ShortName>Stock-Based Compensation, Dividend Restrictions, And Calculations Of Earnings Per Share Of Common Stock (Calculations Of Earnings Per Share Of Common Stock) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R94.htm</HtmlFileName>
      <LongName>1095 - Disclosure - Stock-Based Compensation, Dividend Restrictions, And Calculations Of Earnings Per Share Of Common Stock (Common Stock Reserved And Unissued) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureStockBasedCompensationDividendRestrictionsAndCalculationsOfEarningsPerShareOfCommonStockCommonStockReservedAndUnissued</Role>
      <ShortName>Stock-Based Compensation, Dividend Restrictions, And Calculations Of Earnings Per Share Of Common Stock (Common Stock Reserved And Unissued) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R95.htm</HtmlFileName>
      <LongName>1096 - Disclosure - Derivative Instruments And Hedging Activities (Narrative) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureDerivativeInstrumentsAndHedgingActivitiesNarrative</Role>
      <ShortName>Derivative Instruments And Hedging Activities (Narrative) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R96.htm</HtmlFileName>
      <LongName>1097 - Disclosure - Derivative Instruments And Hedging Activities (Fair Value Of Derivative Instruments by Balance Sheet Location) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureDerivativeInstrumentsAndHedgingActivitiesFairValueOfDerivativeInstrumentsByBalanceSheetLocation</Role>
      <ShortName>Derivative Instruments And Hedging Activities (Fair Value Of Derivative Instruments by Balance Sheet Location) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R97.htm</HtmlFileName>
      <LongName>1098 - Disclosure - Derivative Instruments And Hedging Activities (Schedule Of Cash Collateral Offset Against Derivative Positions) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureDerivativeInstrumentsAndHedgingActivitiesScheduleOfCashCollateralOffsetAgainstDerivativePositions</Role>
      <ShortName>Derivative Instruments And Hedging Activities (Schedule Of Cash Collateral Offset Against Derivative Positions) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R98.htm</HtmlFileName>
      <LongName>1099 - Disclosure - Derivative Instruments And Hedging Activities (Activity Of Energy Commodity Contracts Designated As Cash Flow Hedges) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureDerivativeInstrumentsAndHedgingActivitiesActivityOfEnergyCommodityContractsDesignatedAsCashFlowHedges</Role>
      <ShortName>Derivative Instruments And Hedging Activities (Activity Of Energy Commodity Contracts Designated As Cash Flow Hedges) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R99.htm</HtmlFileName>
      <LongName>1100 - Disclosure - Derivative Instruments And Hedging Activities (Outstanding Energy Commodity Contracts Employed As Cash Flow Hedges) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureDerivativeInstrumentsAndHedgingActivitiesOutstandingEnergyCommodityContractsEmployedAsCashFlowHedges</Role>
      <ShortName>Derivative Instruments And Hedging Activities (Outstanding Energy Commodity Contracts Employed As Cash Flow Hedges) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R100.htm</HtmlFileName>
      <LongName>1101 - Disclosure - Derivative Instruments And Hedging Activities (Net Unrealized Derivative Gain (Loss) Deferred As Regulatory Asset Or Liability) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureDerivativeInstrumentsAndHedgingActivitiesNetUnrealizedDerivativeGainLossDeferredAsRegulatoryAssetOrLiability</Role>
      <ShortName>Derivative Instruments And Hedging Activities (Net Unrealized Derivative Gain (Loss) Deferred As Regulatory Asset Or Liability) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R101.htm</HtmlFileName>
      <LongName>1102 - Disclosure - Derivative Instruments And Hedging Activities (Cash Flow Hedges Included In Accumulated Other Comprehensive Loss) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureDerivativeInstrumentsAndHedgingActivitiesCashFlowHedgesIncludedInAccumulatedOtherComprehensiveLoss</Role>
      <ShortName>Derivative Instruments And Hedging Activities (Cash Flow Hedges Included In Accumulated Other Comprehensive Loss) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R102.htm</HtmlFileName>
      <LongName>1103 - Disclosure - Derivative Instruments And Hedging Activities (Derivative Gain (Loss) Amounts Recognized In Income) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureDerivativeInstrumentsAndHedgingActivitiesDerivativeGainLossAmountsRecognizedInIncome</Role>
      <ShortName>Derivative Instruments And Hedging Activities (Derivative Gain (Loss) Amounts Recognized In Income) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R103.htm</HtmlFileName>
      <LongName>1104 - Disclosure - Derivative Instruments And Hedging Activities (Net Outstanding Commodity Forward Contracts Quantities And Net Position That Did Not Qualify For Hedge Accounting) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureDerivativeInstrumentsAndHedgingActivitiesNetOutstandingCommodityForwardContractsQuantitiesAndNetPositionThatDidNotQualifyForHedgeAccounting</Role>
      <ShortName>Derivative Instruments And Hedging Activities (Net Outstanding Commodity Forward Contracts Quantities And Net Position That Did Not Qualify For Hedge Accounting) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R104.htm</HtmlFileName>
      <LongName>1105 - Disclosure - Derivative Instruments And Hedging Activities (Net Outstanding Commodity Forward Contracts That Did Not Qualify For Hedge Accounting) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureDerivativeInstrumentsAndHedgingActivitiesNetOutstandingCommodityForwardContractsThatDidNotQualifyForHedgeAccounting</Role>
      <ShortName>Derivative Instruments And Hedging Activities (Net Outstanding Commodity Forward Contracts That Did Not Qualify For Hedge Accounting) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R105.htm</HtmlFileName>
      <LongName>1106 - Disclosure - Fair Value Disclosures (Fair Value Of Financial Assets And Liabilities Measured On Recurring Basis) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureFairValueDisclosuresFairValueOfFinancialAssetsAndLiabilitiesMeasuredOnRecurringBasis</Role>
      <ShortName>Fair Value Disclosures (Fair Value Of Financial Assets And Liabilities Measured On Recurring Basis) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R106.htm</HtmlFileName>
      <LongName>1107 - Disclosure - Fair Value Disclosures (Summary Of Primary Unobservable Inputs Used To Determine Fair Value Of Level 3 Instruments And Range Of Values That For Those Inputs) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureFairValueDisclosuresSummaryOfPrimaryUnobservableInputsUsedToDetermineFairValueOfLevel3InstrumentsAndRangeOfValuesThatForThoseInputs</Role>
      <ShortName>Fair Value Disclosures (Summary Of Primary Unobservable Inputs Used To Determine Fair Value Of Level 3 Instruments And Range Of Values That For Those Inputs) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R107.htm</HtmlFileName>
      <LongName>1108 - Disclosure - Fair Value Disclosures (Reconciliations Of Fair Value Measurements Using Significant Unobservable Inputs (Level 3)) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureFairValueDisclosuresReconciliationsOfFairValueMeasurementsUsingSignificantUnobservableInputsLevel3</Role>
      <ShortName>Fair Value Disclosures (Reconciliations Of Fair Value Measurements Using Significant Unobservable Inputs (Level 3)) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R108.htm</HtmlFileName>
      <LongName>1109 - Disclosure - Fair Value Disclosures (Gains Or (Losses) On Level 3 Instruments Included In Income) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureFairValueDisclosuresGainsOrLossesOnLevel3InstrumentsIncludedInIncome</Role>
      <ShortName>Fair Value Disclosures (Gains Or (Losses) On Level 3 Instruments Included In Income) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R109.htm</HtmlFileName>
      <LongName>1110 - Disclosure - Fair Value Disclosures (Fair Value Of Financial Liabilities Measured On Recurring Basis) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureFairValueDisclosuresFairValueOfFinancialLiabilitiesMeasuredOnRecurringBasis</Role>
      <ShortName>Fair Value Disclosures (Fair Value Of Financial Liabilities Measured On Recurring Basis) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R110.htm</HtmlFileName>
      <LongName>1111 - Disclosure - Fair Value Disclosures (Estimated Fair Values Of Debt And Equity Instruments) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureFairValueDisclosuresEstimatedFairValuesOfDebtAndEquityInstruments</Role>
      <ShortName>Fair Value Disclosures (Estimated Fair Values Of Debt And Equity Instruments) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R111.htm</HtmlFileName>
      <LongName>1112 - Disclosure - Commitments And Contingencies (Retained Environmental Exposures) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureCommitmentsAndContingenciesRetainedEnvironmentalExposures</Role>
      <ShortName>Commitments And Contingencies (Retained Environmental Exposures) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R112.htm</HtmlFileName>
      <LongName>1113 - Disclosure - Commitments And Contingencies (Schedule Of Accrued Liabilities For Environmental Exposures) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureCommitmentsAndContingenciesScheduleOfAccruedLiabilitiesForEnvironmentalExposures</Role>
      <ShortName>Commitments And Contingencies (Schedule Of Accrued Liabilities For Environmental Exposures) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R113.htm</HtmlFileName>
      <LongName>1114 - Disclosure - Commitments And Contingencies (Environmental Matters) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureCommitmentsAndContingenciesEnvironmentalMatters</Role>
      <ShortName>Commitments And Contingencies (Environmental Matters) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R114.htm</HtmlFileName>
      <LongName>1115 - Disclosure - Commitments And Contingencies (Tax Legislation, Guarantees, Indemnifications, And Performance Contracts) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureCommitmentsAndContingenciesTaxLegislationGuaranteesIndemnificationsAndPerformanceContracts</Role>
      <ShortName>Commitments And Contingencies (Tax Legislation, Guarantees, Indemnifications, And Performance Contracts) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R115.htm</HtmlFileName>
      <LongName>1116 - Disclosure - Commitments And Contingencies (Schedule Of Commitments And Obligations) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureCommitmentsAndContingenciesScheduleOfCommitmentsAndObligations</Role>
      <ShortName>Commitments And Contingencies (Schedule Of Commitments And Obligations) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R116.htm</HtmlFileName>
      <LongName>1117 - Disclosure - Accumulated Other Comprehensive Loss (Schedule Of Components Of Other Comprehensive Loss) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureAccumulatedOtherComprehensiveLossScheduleOfComponentsOfOtherComprehensiveLoss</Role>
      <ShortName>Accumulated Other Comprehensive Loss (Schedule Of Components Of Other Comprehensive Loss) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R117.htm</HtmlFileName>
      <LongName>1118 - Disclosure - Accumulated Other Comprehensive Loss (Schedule Of Income Tax Expense (Benefit) Allocated To Accumulated Other Comprehensive Income Loss) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureAccumulatedOtherComprehensiveLossScheduleOfIncomeTaxExpenseBenefitAllocatedToAccumulatedOtherComprehensiveIncomeLoss</Role>
      <ShortName>Accumulated Other Comprehensive Loss (Schedule Of Income Tax Expense (Benefit) Allocated To Accumulated Other Comprehensive Income Loss) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R118.htm</HtmlFileName>
      <LongName>1119 - Disclosure - Quarterly Financial Information (Schedule Of Quarterly Financial Information) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureQuarterlyFinancialInformationScheduleOfQuarterlyFinancialInformation</Role>
      <ShortName>Quarterly Financial Information (Schedule Of Quarterly Financial Information) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R119.htm</HtmlFileName>
      <LongName>1120 - Disclosure - Quarterly Financial Information (Narrative) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureQuarterlyFinancialInformationNarrative</Role>
      <ShortName>Quarterly Financial Information (Narrative) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R120.htm</HtmlFileName>
      <LongName>1121 - Disclosure - Discontinued Operations (Narrative) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureDiscontinuedOperationsNarrative</Role>
      <ShortName>Discontinued Operations (Narrative) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R121.htm</HtmlFileName>
      <LongName>1122 - Disclosure - Subsequent Event (Narrative) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureSubsequentEventNarrative</Role>
      <ShortName>Subsequent Event (Narrative) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R122.htm</HtmlFileName>
      <LongName>1123 - Disclosure - Related Party Transactions (Narrative) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureRelatedPartyTransactionsNarrative</Role>
      <ShortName>Related Party Transactions (Narrative) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R123.htm</HtmlFileName>
      <LongName>1124 - Disclosure - Related Party Transactions (Schedule Of Related Party Transactions Included In Balance Sheet) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureRelatedPartyTransactionsScheduleOfRelatedPartyTransactionsIncludedInBalanceSheet</Role>
      <ShortName>Related Party Transactions (Schedule Of Related Party Transactions Included In Balance Sheet) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R124.htm</HtmlFileName>
      <LongName>1125 - Disclosure - Related Party Transactions (Schedule Of Related Party Transactions Included In Income Statement) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureRelatedPartyTransactionsScheduleOfRelatedPartyTransactionsIncludedInIncomeStatement</Role>
      <ShortName>Related Party Transactions (Schedule Of Related Party Transactions Included In Income Statement) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R125.htm</HtmlFileName>
      <LongName>1126 - Disclosure - Schedule I - Condensed Financial Information Of Parent Company (Statements Of Income) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureScheduleICondensedFinancialInformationOfParentCompanyStatementsOfIncome</Role>
      <ShortName>Schedule I - Condensed Financial Information Of Parent Company (Statements Of Income) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R126.htm</HtmlFileName>
      <LongName>1127 - Disclosure - Schedule I - Condensed Financial Information Of Parent Company (Balance Sheets) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureScheduleICondensedFinancialInformationOfParentCompanyBalanceSheets</Role>
      <ShortName>Schedule I - Condensed Financial Information Of Parent Company (Balance Sheets) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R127.htm</HtmlFileName>
      <LongName>1128 - Disclosure - Schedule I - Condensed Financial Information Of Parent Company (Balance Sheets) (Parenthetical) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureScheduleICondensedFinancialInformationOfParentCompanyBalanceSheetsParenthetical</Role>
      <ShortName>Schedule I - Condensed Financial Information Of Parent Company (Balance Sheets) (Parenthetical) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R128.htm</HtmlFileName>
      <LongName>1129 - Disclosure - Schedule I - Condensed Financial Information Of Parent Company (Statements Of Cash Flows) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureScheduleICondensedFinancialInformationOfParentCompanyStatementsOfCashFlows</Role>
      <ShortName>Schedule I - Condensed Financial Information Of Parent Company (Statements Of Cash Flows) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R129.htm</HtmlFileName>
      <LongName>1130 - Disclosure - Schedule I - Condensed Financial Information Of Parent Company (Narrative) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureScheduleICondensedFinancialInformationOfParentCompanyNarrative</Role>
      <ShortName>Schedule I - Condensed Financial Information Of Parent Company (Narrative) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R130.htm</HtmlFileName>
      <LongName>1131 - Disclosure - Schedule I - Condensed Financial Information Of Parent Company (Investment In Consolidated Companies) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureScheduleICondensedFinancialInformationOfParentCompanyInvestmentInConsolidatedCompanies</Role>
      <ShortName>Schedule I - Condensed Financial Information Of Parent Company (Investment In Consolidated Companies) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R131.htm</HtmlFileName>
      <LongName>1132 - Disclosure - Schedule I - Condensed Financial Information Of Parent Company (Related Party Transactions) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureScheduleICondensedFinancialInformationOfParentCompanyRelatedPartyTransactions</Role>
      <ShortName>Schedule I - Condensed Financial Information Of Parent Company (Related Party Transactions) (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R132.htm</HtmlFileName>
      <LongName>1133 - Disclosure - Schedule II - Valuation And Qualifying Accounts (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pepcoholdings.com/taxonomy/role/DisclosureScheduleIIValuationAndQualifyingAccounts</Role>
      <ShortName>Schedule II - Valuation And Qualifying Accounts (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <Logs>
    <Log type="Info">Element pom_BondsRedeemed had a mix of decimals attribute values: -6 -5.</Log>
    <Log type="Info">Element pom_IncrementalStormCosts had a mix of decimals attribute values: -6 -5.</Log>
    <Log type="Info">Element us-gaap_AssetsHeldInTrustNoncurrent had a mix of decimals attribute values: -8 -6.</Log>
    <Log type="Info">Element us-gaap_DefinedBenefitPlanBenefitObligation had a mix of decimals attribute values: -8 -6.</Log>
    <Log type="Info">Element us-gaap_DefinedBenefitPlanHealthCareCostTrendRateAssumedForNextFiscalYear had a mix of decimals attribute values: 0 4.</Log>
    <Log type="Info">Element us-gaap_FairValueInputsDiscountRate had a mix of decimals attribute values: 0 2.</Log>
    <Log type="Info">Element us-gaap_StockIssuedDuringPeriodSharesDividendReinvestmentPlan had a mix of decimals attribute values: -6 0.</Log>
    <Log type="Info">'Monetary' elements on report '1059 - Disclosure - Leasing Activities (Narrative) (Detail)' had a mix of different decimal attribute values.</Log>
    <Log type="Info">'Monetary' elements on report '1067 - Disclosure - Pension And Other Postretirement Benefits (Narrative) (Detail)' had a mix of different decimal attribute values.</Log>
    <Log type="Info">'Monetary' elements on report '1082 - Disclosure - Debt (Narrative) (Detail)' had a mix of different decimal attribute values.</Log>
    <Log type="Info">'Shares' elements on report '1090 - Disclosure - Stock-Based Compensation, Dividend Restrictions, And Calculations Of Earnings Per Share Of Common Stock (Narrative) (Detail)' had a mix of different decimal attribute values.</Log>
    <Log type="Info">'Monetary' elements on report '1090 - Disclosure - Stock-Based Compensation, Dividend Restrictions, And Calculations Of Earnings Per Share Of Common Stock (Narrative) (Detail)' had a mix of different decimal attribute values.</Log>
    <Log type="Info">'Shares' elements on report '1094 - Disclosure - Stock-Based Compensation, Dividend Restrictions, And Calculations Of Earnings Per Share Of Common Stock (Calculations Of Earnings Per Share Of Common Stock) (Detail)' had a mix of different decimal attribute values.</Log>
    <Log type="Info">'Monetary' elements on report '1114 - Disclosure - Commitments And Contingencies (Environmental Matters) (Detail)' had a mix of different decimal attribute values.</Log>
    <Log type="Info">Process Flow-Through: 1003 - Statement - Consolidated Statements Of Income</Log>
    <Log type="Info">	Process Flow-Through: Removing column '3 Months Ended
Dec. 31, 2012'</Log>
    <Log type="Info">	Process Flow-Through: Removing column '3 Months Ended
Sep. 30, 2012'</Log>
    <Log type="Info">	Process Flow-Through: Removing column '3 Months Ended
Jun. 30, 2012'</Log>
    <Log type="Info">	Process Flow-Through: Removing column '3 Months Ended
Mar. 31, 2012'</Log>
    <Log type="Info">	Process Flow-Through: Removing column '3 Months Ended
Dec. 31, 2011'</Log>
    <Log type="Info">	Process Flow-Through: Removing column '3 Months Ended
Sep. 30, 2011'</Log>
    <Log type="Info">	Process Flow-Through: Removing column '3 Months Ended
Jun. 30, 2011'</Log>
    <Log type="Info">	Process Flow-Through: Removing column '3 Months Ended
Mar. 31, 2011'</Log>
    <Log type="Info">Process Flow-Through: 1004 - Statement - Consolidated Statements Of Comprehensive Income</Log>
    <Log type="Info">	Process Flow-Through: Removing column '3 Months Ended
Dec. 31, 2012'</Log>
    <Log type="Info">	Process Flow-Through: Removing column '3 Months Ended
Sep. 30, 2012'</Log>
    <Log type="Info">	Process Flow-Through: Removing column '3 Months Ended
Jun. 30, 2012'</Log>
    <Log type="Info">	Process Flow-Through: Removing column '3 Months Ended
Mar. 31, 2012'</Log>
    <Log type="Info">	Process Flow-Through: Removing column '3 Months Ended
Dec. 31, 2011'</Log>
    <Log type="Info">	Process Flow-Through: Removing column '3 Months Ended
Sep. 30, 2011'</Log>
    <Log type="Info">	Process Flow-Through: Removing column '3 Months Ended
Jun. 30, 2011'</Log>
    <Log type="Info">	Process Flow-Through: Removing column '3 Months Ended
Mar. 31, 2011'</Log>
    <Log type="Info">Process Flow-Through: 1005 - Statement - Consolidated Balance Sheets</Log>
    <Log type="Info">	Process Flow-Through: Removing column 'Dec. 31, 2010'</Log>
    <Log type="Info">	Process Flow-Through: Removing column 'Dec. 31, 2009'</Log>
    <Log type="Info">Process Flow-Through: 1006 - Statement - Consolidated Balance Sheets (Parenthetical)</Log>
    <Log type="Info">Process Flow-Through: 1007 - Statement - Consolidated Statements Of Cash Flows</Log>
    <Log type="Info">Process Flow-Through: 1008 - Statement - Consolidated Statements Of Cash Flows (Parenthetical)</Log>
    <Log type="Info">Process Flow-Through: 1010 - Statement - Consolidated Statements Of Equity (Parenthetical)</Log>
  </Logs>
  <InputFiles>
    <File>pom-20121231.xml</File>
    <File>pom-20121231.xsd</File>
    <File>pom-20121231_cal.xml</File>
    <File>pom-20121231_def.xml</File>
    <File>pom-20121231_lab.xml</File>
    <File>pom-20121231_pre.xml</File>
  </InputFiles>
  <SupplementalFiles />
  <BaseTaxonomies />
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
