Baltimore Gas and Electric Company [Member] Baltimore Gas and Electric Company [Member] Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Entity Address, City or Town Entity Address, City or Town Soliciting Material Soliciting Material Entity Address, Address Line One Entity Address, Address Line One Security Exchange Name Security Exchange Name Entity Address, Address Line Two Entity Address, Address Line Two Document Information [Line Items] Document Information [Line Items] City Area Code City Area Code Cover page. Cover [Abstract] Entity Central Index Key Entity Central Index Key Entity Tax Identification Number Entity Tax Identification Number Entity File Number Entity File Number Document Type Document Type Geographical [Axis] Geographical [Axis] Potomac Electric Power Company [Member] Potomac Electric Power Company [Member] Potomac Electric Power Company [Member] PECO Energy Co [Member] PECO Energy Co [Member] PECO Energy Co [Member] Document Information [Table] Document Information [Table] Entity Emerging Growth Company Entity Emerging Growth Company Geographical [Domain] Geographical [Domain] Title of 12(b) Security Title of 12(b) Security Document Information, Document [Axis] Document Information, Document [Axis] Amendment Flag Amendment Flag Entity Address, State or Province Entity Address, State or Province DELAWARE DELAWARE Trading Symbol Trading Symbol Document Period End Date Document Period End Date Entity Registrant Name Entity Registrant Name Written Communications Written Communications Pre-commencement Tender Offer Pre-commencement Tender Offer Delmarva Power and Light Company [Member] Delmarva Power and Light Company [Member] Delmarva Power and Light Company [Member] Exelon Generation Co L L C [Member] Exelon Generation Co L L C [Member] Exelon Generation Co LLC [Member] Legal Entity [Axis] Legal Entity [Axis] Pepco Holdings LLC [Member] Pepco Holdings LLC [Member] Pepco Holdings LLC [Member] Commonwealth Edison Co [Member] Commonwealth Edison Co [Member] Commonwealth Edison Co [Member] DISTRICT OF COLUMBIA DISTRICT OF COLUMBIA Local Phone Number Local Phone Number Entity Address, Postal Zip Code Entity Address, Postal Zip Code VIRGINIA VIRGINIA Entity [Domain] Entity [Domain] Pre-commencement Issuer Tender Offer Pre-commencement Issuer Tender Offer Atlantic City Electric Company [Member] Atlantic City Electric Company [Member] Atlantic City Electric Company [Member] Document [Domain] Document [Domain]