1.0.0.3 true PENSION AND OTHER POSTRETIREMENT BENEFITS false 1 $ true false false false PEPCO HOLDINGS INC dei_LegalEntityAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_ParentCompanyMember dei_LegalEntityAxis explicitMember Shares Standard http://www.xbrl.org/2003/instance shares 0 USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 USDperShareItemType Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares 0 1 PEPCO HOLDINGS INC 0 na true na na na No definition available. false true false false false false false false false 1 false false 0 0 false false No definition available. No authoritative reference available. false 2 Notes to Financial Statements [Abstract] 2 pom false na duration string Notes to Financial Statements [Abstract] false false false false false true false false false 1 false false 0 0 false false Notes to Financial Statements [Abstract] false 3 PENSION AND OTHER POSTRETIREMENT BENEFITS 2 us-gaap_PensionAndOtherPostretirementBenefitsDisclosureTextBlock us-gaap true na duration string No definition available. false false false false false false false false false 1 false false 0 0 <div> (8) PENSIONS AND OTHER POSTRETIREMENT BENEFITS The following Pepco Holdings information is for the three months ended September 30, 2009 and 2008:   <table border="0" cellspacing="0" cellpadding="0" width="100%" align="center"> <tr> <td width="80%"></td> <td valign="bottom" width="3%"></td> <td></td> <td></td> <td></td> <td valign="bottom" width="3%"></td> <td></td> <td></td> <td></td> <td valign="bottom" width="3%"></td> <td></td> <td></td> <td></td> <td valign="bottom" width="3%"></td> <td></td> <td></td> <td></td> </tr> <tr> <td valign="bottom"> </td> <td valign="bottom">  </td> <td style="BORDER-BOTTOM: #000000 1px solid" valign="bottom" colspan="6" align="center">Pension Benefits</td> <td valign="bottom"> </td> <td valign="bottom"> </td> <td style="BORDER-BOTTOM: #000000 1px solid" valign="bottom" colspan="6" align="center">Other Postretirement Benefits</td> <td valign="bottom"> </td> </tr> <tr> <td valign="bottom"> </td> <td valign="bottom">  </td> <td style="BORDER-BOTTOM: #000000 1px solid" valign="bottom" colspan="2" align="center">2009</td> <td valign="bottom"> </td> <td valign="bottom"> </td> <td style="BORDER-BOTTOM: #000000 1px solid" valign="bottom" colspan="2" align="center">2008</td> <td valign="bottom"> </td> <td valign="bottom"> </td> <td style="BORDER-BOTTOM: #000000 1px solid" valign="bottom" colspan="2" align="center">2009</td> <td valign="bottom"> </td> <td valign="bottom"> </td> <td style="BORDER-BOTTOM: #000000 1px solid" valign="bottom" colspan="2" align="center">2008</td> <td valign="bottom"> </td> </tr> <tr> <td valign="bottom"> </td> <td valign="bottom">  </td> <td valign="bottom" colspan="14" align="center">(millions of dollars)</td> <td valign="bottom"> </td> </tr> <tr bgcolor="#CCEEFF"> <td valign="top"> Service cost </td> <td valign="bottom">  </td> <td valign="bottom">$</td> <td valign="bottom" align="right">9</td> <td valign="bottom" nowrap="nowrap"> </td> <td valign="bottom"> </td> <td valign="bottom">$</td> <td valign="bottom" align="right">9</td> <td valign="bottom" nowrap="nowrap">  </td> <td valign="bottom"> </td> <td valign="bottom">$</td> <td valign="bottom" align="right">2</td> <td valign="bottom" nowrap="nowrap"> </td> <td valign="bottom"> </td> <td valign="bottom">$</td> <td valign="bottom" align="right">2</td> <td valign="bottom" nowrap="nowrap"> </td> </tr> <tr> <td valign="top"> Interest cost </td> <td valign="bottom">  </td> <td valign="bottom"> </td> <td valign="bottom" align="right">27</td> <td valign="bottom" nowrap="nowrap"> </td> <td valign="bottom"> </td> <td valign="bottom"> </td> <td valign="bottom" align="right">27</td> <td valign="bottom" nowrap="nowrap"> </td> <td valign="bottom"> </td> <td valign="bottom"> </td> <td valign="bottom" align="right">10</td> <td valign="bottom" nowrap="nowrap"> </td> <td valign="bottom"> </td> <td valign="bottom"> </td> <td valign="bottom" align="right">10</td> <td valign="bottom" nowrap="nowrap"> </td> </tr> <tr bgcolor="#CCEEFF"> <td valign="top"> Expected return on plan assets </td> <td valign="bottom">  </td> <td valign="bottom"> </td> <td valign="bottom" align="right">(25</td> <td valign="bottom" nowrap="nowrap">)</td> <td valign="bottom"> </td> <td valign="bottom"> </td> <td valign="bottom" align="right">(33</td> <td valign="bottom" nowrap="nowrap">)</td> <td valign="bottom"> </td> <td valign="bottom"> </td> <td valign="bottom" align="right">(3</td> <td valign="bottom" nowrap="nowrap">)</td> <td valign="bottom"> </td> <td valign="bottom"> </td> <td valign="bottom" align="right">(4</td> <td valign="bottom" nowrap="nowrap">)</td> </tr> <tr> <td valign="top"> Prior service credit component </td> <td valign="bottom">  </td> <td valign="bottom"> </td> <td valign="bottom" align="right">—  </td> <td valign="bottom" nowrap="nowrap">  </td> <td valign="bottom"> </td> <td valign="bottom"> </td> <td valign="bottom" align="right">—  </td> <td valign="bottom" nowrap="nowrap">  </td> <td valign="bottom"> </td> <td valign="bottom"> </td> <td valign="bottom" align="right">(1</td> <td valign="bottom" nowrap="nowrap">)</td> <td valign="bottom"> </td> <td valign="bottom"> </td> <td valign="bottom" align="right">(1</td> <td valign="bottom" nowrap="nowrap">)</td> </tr> <tr bgcolor="#CCEEFF"> <td valign="top"> Loss component </td> <td valign="bottom">  </td> <td valign="bottom"> </td> <td valign="bottom" align="right">14</td> <td valign="bottom" nowrap="nowrap"> </td> <td valign="bottom"> </td> <td valign="bottom"> </td> <td valign="bottom" align="right">3</td> <td valign="bottom" nowrap="nowrap"> </td> <td valign="bottom"> </td> <td valign="bottom"> </td> <td valign="bottom" align="right">3</td> <td valign="bottom" nowrap="nowrap"> </td> <td valign="bottom"> </td> <td valign="bottom"> </td> <td valign="bottom" align="right">3</td> <td valign="bottom" nowrap="nowrap"> </td> </tr> <tr style="FONT-SIZE: 1px"> <td valign="bottom"></td> <td valign="bottom">  </td> <td style="BORDER-TOP: #000000 1px solid" valign="bottom">  </td> <td style="BORDER-TOP: #000000 1px solid" valign="bottom">  </td> <td> </td> <td valign="bottom"> </td> <td style="BORDER-TOP: #000000 1px solid" valign="bottom">  </td> <td style="BORDER-TOP: #000000 1px solid" valign="bottom">  </td> <td> </td> <td valign="bottom"> </td> <td style="BORDER-TOP: #000000 1px solid" valign="bottom">  </td> <td style="BORDER-TOP: #000000 1px solid" valign="bottom">  </td> <td> </td> <td valign="bottom"> </td> <td style="BORDER-TOP: #000000 1px solid" valign="bottom">  </td> <td style="BORDER-TOP: #000000 1px solid" valign="bottom">  </td> <td> </td> </tr> <tr> <td valign="top"> Net periodic benefit cost </td> <td valign="bottom">  </td> <td valign="bottom">$</td> <td valign="bottom" align="right">25</td> <td valign="bottom" nowrap="nowrap"> </td> <td valign="bottom"> </td> <td valign="bottom">$</td> <td valign="bottom" align="right">6</td> <td valign="bottom" nowrap="nowrap"> </td> <td valign="bottom"> </td> <td valign="bottom">$</td> <td valign="bottom" align="right">11</td> <td valign="bottom" nowrap="nowrap"> </td> <td valign="bottom"> </td> <td valign="bottom">$</td> <td valign="bottom" align="right">10</td> <td valign="bottom" nowrap="nowrap">  </td> </tr> <tr style="FONT-SIZE: 1px"> <td valign="bottom"></td> <td valign="bottom">  </td> <td style="BORDER-TOP: #000000 3px double" valign="bottom">  </td> <td style="BORDER-TOP: #000000 3px double" valign="bottom">  </td> <td> </td> <td valign="bottom"> </td> <td style="BORDER-TOP: #000000 3px double" valign="bottom">  </td> <td style="BORDER-TOP: #000000 3px double" valign="bottom">  </td> <td> </td> <td valign="bottom"> </td> <td style="BORDER-TOP: #000000 3px double" valign="bottom">  </td> <td style="BORDER-TOP: #000000 3px double" valign="bottom">  </td> <td> </td> <td valign="bottom"> </td> <td style="BORDER-TOP: #000000 3px double" valign="bottom">  </td> <td style="BORDER-TOP: #000000 3px double" valign="bottom">  </td> <td> </td> </tr> </table> The following Pepco Holdings information is for the nine months ended September 30, 2009 and 2008:   <table border="0" cellspacing="0" cellpadding="0" width="100%" align="center"> <tr> <td width="80%"></td> <td valign="bottom" width="3%"></td> <td></td> <td></td> <td></td> <td valign="bottom" width="3%"></td> <td></td> <td></td> <td></td> <td valign="bottom" width="3%"></td> <td></td> <td></td> <td></td> <td valign="bottom" width="3%"></td> <td></td> <td></td> <td></td> </tr> <tr> <td valign="bottom"> </td> <td valign="bottom">  </td> <td style="BORDER-BOTTOM: #000000 1px solid" valign="bottom" colspan="6" align="center">Pension Benefits</td> <td valign="bottom"> </td> <td valign="bottom"> </td> <td style="BORDER-BOTTOM: #000000 1px solid" valign="bottom" colspan="6" align="center">Other Postretirement Benefits</td> <td valign="bottom"> </td> </tr> <tr> <td valign="bottom"> </td> <td valign="bottom">  </td> <td style="BORDER-BOTTOM: #000000 1px solid" valign="bottom" colspan="2" align="center">2009</td> <td valign="bottom"> </td> <td valign="bottom"> </td> <td style="BORDER-BOTTOM: #000000 1px solid" valign="bottom" colspan="2" align="center">2008</td> <td valign="bottom"> </td> <td valign="bottom"> </td> <td style="BORDER-BOTTOM: #000000 1px solid" valign="bottom" colspan="2" align="center">2009</td> <td valign="bottom"> </td> <td valign="bottom"> </td> <td style="BORDER-BOTTOM: #000000 1px solid" valign="bottom" colspan="2" align="center">2008</td> <td valign="bottom"> </td> </tr> <tr> <td valign="bottom"> </td> <td valign="bottom">  </td> <td valign="bottom" colspan="14" align="center">(millions of dollars)</td> <td valign="bottom"> </td> </tr> <tr bgcolor="#CCEEFF"> <td valign="top"> Service cost </td> <td valign="bottom">  </td> <td valign="bottom">$</td> <td valign="bottom" align="right">27</td> <td valign="bottom" nowrap="nowrap"> </td> <td valign="bottom"> </td> <td valign="bottom">$</td> <td valign="bottom" align="right">27</td> <td valign="bottom" nowrap="nowrap"> </td> <td valign="bottom"> </td> <td valign="bottom">$</td> <td valign="bottom" align="right">5</td> <td valign="bottom" nowrap="nowrap"> </td> <td valign="bottom"> </td> <td valign="bottom">$</td> <td valign="bottom" align="right">5</td> <td valign="bottom" nowrap="nowrap"> </td> </tr> <tr> <td valign="top"> Interest cost </td> <td valign="bottom">  </td> <td valign="bottom"> </td> <td valign="bottom" align="right">83</td> <td valign="bottom" nowrap="nowrap"> </td> <td valign="bottom"> </td> <td valign="bottom"> </td> <td valign="bottom" align="right">81</td> <td valign="bottom" nowrap="nowrap"> </td> <td valign="bottom"> </td> <td valign="bottom"> </td> <td valign="bottom" align="right">30</td> <td valign="bottom" nowrap="nowrap"> </td> <td valign="bottom"> </td> <td valign="bottom"> </td> <td valign="bottom" align="right">30</td> <td valign="bottom" nowrap="nowrap"> </td> </tr> <tr bgcolor="#CCEEFF"> <td valign="top"> Expected return on plan assets </td> <td valign="bottom">  </td> <td valign="bottom"> </td> <td valign="bottom" align="right">(76</td> <td valign="bottom" nowrap="nowrap">) </td> <td valign="bottom"> </td> <td valign="bottom"> </td> <td valign="bottom" align="right">(97</td> <td valign="bottom" nowrap="nowrap">) </td> <td valign="bottom"> </td> <td valign="bottom"> </td> <td valign="bottom" align="right">(10</td> <td valign="bottom" nowrap="nowrap">)</td> <td valign="bottom"> </td> <td valign="bottom"> </td> <td valign="bottom" align="right">(12</td> <td valign="bottom" nowrap="nowrap">)</td> </tr> <tr> <td valign="top"> Prior service credit component </td> <td valign="bottom">  </td> <td valign="bottom"> </td> <td valign="bottom" align="right">—  </td> <td valign="bottom" nowrap="nowrap">  </td> <td valign="bottom"> </td> <td valign="bottom"> </td> <td valign="bottom" align="right">—  </td> <td valign="bottom" nowrap="nowrap">  </td> <td valign="bottom"> </td> <td valign="bottom"> </td> <td valign="bottom" align="right">(3</td> <td valign="bottom" nowrap="nowrap">)</td> <td valign="bottom"> </td> <td valign="bottom"> </td> <td valign="bottom" align="right">(3</td> <td valign="bottom" nowrap="nowrap">)</td> </tr> <tr bgcolor="#CCEEFF"> <td valign="top"> Loss component </td> <td valign="bottom">  </td> <td valign="bottom"> </td> <td valign="bottom" align="right">43</td> <td valign="bottom" nowrap="nowrap"> </td> <td valign="bottom"> </td> <td valign="bottom"> </td> <td valign="bottom" align="right">7</td> <td valign="bottom" nowrap="nowrap"> </td> <td valign="bottom"> </td> <td valign="bottom"> </td> <td valign="bottom" align="right">12</td> <td valign="bottom" nowrap="nowrap"> </td> <td valign="bottom"> </td> <td valign="bottom"> </td> <td valign="bottom" align="right">10</td> <td valign="bottom" nowrap="nowrap"> </td> </tr> <tr style="FONT-SIZE: 1px"> <td valign="bottom"></td> <td valign="bottom">  </td> <td style="BORDER-TOP: #000000 1px solid" valign="bottom">  </td> <td style="BORDER-TOP: #000000 1px solid" valign="bottom">  </td> <td> </td> <td valign="bottom"> </td> <td style="BORDER-TOP: #000000 1px solid" valign="bottom">  </td> <td style="BORDER-TOP: #000000 1px solid" valign="bottom">  </td> <td> </td> <td valign="bottom"> </td> <td style="BORDER-TOP: #000000 1px solid" valign="bottom">  </td> <td style="BORDER-TOP: #000000 1px solid" valign="bottom">  </td> <td> </td> <td valign="bottom"> </td> <td style="BORDER-TOP: #000000 1px solid" valign="bottom">  </td> <td style="BORDER-TOP: #000000 1px solid" valign="bottom">  </td> <td> </td> </tr> <tr> <td valign="top"> Net periodic benefit cost </td> <td valign="bottom">  </td> <td valign="bottom">$</td> <td valign="bottom" align="right">77</td> <td valign="bottom" nowrap="nowrap"> </td> <td valign="bottom"> </td> <td valign="bottom">$</td> <td valign="bottom" align="right">18</td> <td valign="bottom" nowrap="nowrap">  </td> <td valign="bottom"> </td> <td valign="bottom">$</td> <td valign="bottom" align="right">34</td> <td valign="bottom" nowrap="nowrap"> </td> <td valign="bottom"> </td> <td valign="bottom">$</td> <td valign="bottom" align="right">30</td> <td valign="bottom" nowrap="nowrap">  </td> </tr> <tr style="FONT-SIZE: 1px"> <td valign="bottom"></td> <td valign="bottom">  </td> <td style="BORDER-TOP: #000000 3px double" valign="bottom">  </td> <td style="BORDER-TOP: #000000 3px double" valign="bottom">  </td> <td> </td> <td valign="bottom"> </td> <td style="BORDER-TOP: #000000 3px double" valign="bottom">  </td> <td style="BORDER-TOP: #000000 3px double" valign="bottom">  </td> <td> </td> <td valign="bottom"> </td> <td style="BORDER-TOP: #000000 3px double" valign="bottom">  </td> <td style="BORDER-TOP: #000000 3px double" valign="bottom">  </td> <td> </td> <td valign="bottom"> </td> <td style="BORDER-TOP: #000000 3px double" valign="bottom">  </td> <td style="BORDER-TOP: #000000 3px double" valign="bottom">  </td> <td> </td> </tr> </table> Pension and Other Postretirement Benefits Net periodic benefit cost is included in other operation and maintenance expense, net of the portion of the net periodic benefit cost that is capitalized as part of the cost of labor for internal construction projects. After intercompany allocations, the three utility subsidiaries are generally responsible for approximately 80% to 85% of total PHI net periodic benefit cost. Pension Contributions PHI’s funding policy with regard to PHI’s non contributory retirement plan (the PHI Retirement Plan) is to maintain a funding level that is at least equal to the funding target as defined under the Pension Protection Act of 2006. During 2009, discretionary tax-deductible contributions totaling $300 million have been made to the PHI Retirement Plan which are expected to bring plan assets to at least the funding target level for 2009 under the Pension Protection Act. Of this amount, $240 million was contributed, through tax-deductible contributions from Pepco, ACE and DPL in the amounts of $170 million, $60 million and $10 million, respectively. The remaining $60 million was made through tax-deductible contributions from the PHI Service Company. No contributions were made in 2008. </div> false false No definition available. No authoritative reference available. false 4 POTOMAC ELECTRIC POWER CO 0 na true na na na No definition available. false true false false false false false false false 1 false false 0 0 false false No definition available. No authoritative reference available. false 5 Notes to Financial Statements [Abstract] 2 pom false na duration string Notes to Financial Statements [Abstract] false false false false false true false false false 1 false false 0 0 false false Notes to Financial Statements [Abstract] false 6 PENSION AND OTHER POSTRETIREMENT BENEFITS 2 us-gaap_PensionAndOtherPostretirementBenefitsDisclosureTextBlock us-gaap true na duration string No definition available. false false false false false false false false false 1 false false 0 0 <div> (6) PENSIONS AND OTHER POSTRETIREMENT BENEFITS Pepco accounts for its participation in the Pepco Holdings benefit plans as participation in a multi-employer plan. PHI’s pension and other postretirement net periodic benefit cost for the three months ended September 30, 2009 before intercompany allocations from the PHI Service Company, of $36 million included $9 million for Pepco’s allocated share. PHI’s pension and other postretirement net periodic benefit cost for the nine months ended September 30, 2009 of $111 million included $28 million for Pepco’s allocated share. PHI’s pension and other postretirement net periodic benefit cost for the three months ended September 30, 2008, of $16 million, before intercompany allocations, included $6 million for Pepco’s allocated share. PHI’s pension and other postretirement net periodic benefit cost for the nine months ended September 30, 2008 of $48 million included $18 million for Pepco’s allocated share. </div> false false No definition available. No authoritative reference available. false 7 DELMARVA POWER & LIGHT CO /DE/ 0 na true na na na No definition available. false true false false false false false false false 1 false false 0 0 false false No definition available. No authoritative reference available. false 8 Notes to Financial Statements [Abstract] 2 pom false na duration string Notes to Financial Statements [Abstract] false false false false false true false false false 1 false false 0 0 false false Notes to Financial Statements [Abstract] false 9 PENSION AND OTHER POSTRETIREMENT BENEFITS 2 us-gaap_PensionAndOtherPostretirementBenefitsDisclosureTextBlock us-gaap true na duration string No definition available. false false false false false false false false false 1 false false 0 0 <div> (7) PENSION AND OTHER POSTRETIREMENT BENEFITS DPL accounts for its participation in the Pepco Holdings benefit plans as participation in a multi-employer plan. PHI’s pension and other postretirement net periodic benefit cost for the three months ended September 30, 2009 before intercompany allocations from the PHI Service Company, of $36 million included $6 million for DPL’s allocated share. PHI’s pension and other post retirement net periodic benefit cost for the nine months ended September 30, 2009 of $111 million included $19 million for DPL’s allocated share. PHI’s pension and other postretirement net periodic benefit cost for the three months ended September 30, 2008 before intercompany allocations, of $16 million included $1 million for DPL’s allocated share. PHI’s pension and other post retirement net periodic benefit cost for the nine months ended September 30, 2008 of $48 million included $3 million for DPL’s allocated share. </div> false false No definition available. No authoritative reference available. false 10 ATLANTIC CITY ELECTRIC CO 0 na true na na na No definition available. false true false false false false false false false 1 false false 0 0 false false No definition available. No authoritative reference available. false 11 Notes to Financial Statements [Abstract] 2 pom false na duration string Notes to Financial Statements [Abstract] false false false false false true false false false 1 false false 0 0 false false Notes to Financial Statements [Abstract] false 12 PENSION AND OTHER POSTRETIREMENT BENEFITS 2 us-gaap_PensionAndOtherPostretirementBenefitsDisclosureTextBlock us-gaap true na duration string No definition available. false false false false false false false false false 1 false false 0 0 <div> (6) PENSION AND OTHER POSTRETIREMENT BENEFITS ACE accounts for its participation in the Pepco Holdings benefit plans as participation in a multi-employer plan. PHI’s pension and other postretirement net periodic benefit cost for the three months ended September 30, 2009 before intercompany allocations from the PHI Service Company, of $36 million included $5 million for ACE’s allocated share. PHI’s pension and other postretirement net periodic benefit cost for the nine months ended September 30, 2009 of $111 million included $15 million for ACE’s allocated share. PHI’s pension and other postretirement net periodic benefit cost for the three months ended September 30, 2008 before intercompany allocations, of $16 million included $3 million for ACE’s allocated share. PHI’s pension and other postretirement net periodic benefit cost for the nine months ended September 30, 2008 of $48 million included $9 million for ACE’s allocated share. </div> false false No definition available. No authoritative reference available. false false 1 12 false UnKnown UnKnown UnKnown false true