Commitments And Contingencies (Schedule Of Commitments And Obligations) (Details) (USD $)	3 Months Ended
	Mar. 31, 2012
Commitments And Contingencies [Line Items]
Energy procurement obligations of Pepco Energy Services	$ 160,000,000	[1]
Guarantees associated with disposal of Conectiv Energy assets	18,000,000	[2]
Guaranteed lease residual values	14,000,000	[3]
Total	192,000,000
Guaranteed amounts on the transferred tolling agreements	5,000,000
Derivative portfolio guarantee	13,000,000
Obligations under guarantees	14,000,000
Pepco Holdings Inc [Member]
Commitments And Contingencies [Line Items]
Energy procurement obligations of Pepco Energy Services	160,000,000	[1]
Guarantees associated with disposal of Conectiv Energy assets	18,000,000	[2]
Guaranteed lease residual values	2,000,000	[3]
Total	180,000,000
Potomac Electric Power Co [Member]
Commitments And Contingencies [Line Items]
Guaranteed lease residual values	4,000,000	[3]
Total	4,000,000
Delmarva Power & Light Co/De [Member]
Commitments And Contingencies [Line Items]
Guaranteed lease residual values	5,000,000	[3]
Total	5,000,000
Atlantic City Electric Co [Member]
Commitments And Contingencies [Line Items]
Guaranteed lease residual values	3,000,000	[3]
Total	$ 3,000,000
Minimum [Member]
Commitments And Contingencies [Line Items]
Guaranteed lease residual values, period	2 years
Maximum [Member]
Commitments And Contingencies [Line Items]
Guaranteed lease residual values, period	10 years

[1] PHI has contractual commitments for performance and related payments of Pepco Energy Services to counterparties under routine energy sales and procurement obligations.

[2] Represents guarantees by PHI of Conectiv Energy's tolling agreements and derivatives portfolio transferred in connection with the disposition of Conectiv Energy's wholesale business. The tolling agreement guarantees cover the payment by the entity to which the tolling agreement was assigned. The guaranteed amounts on the transferred tolling agreements totaled $5 million at March 31, 2012 and decline until the termination of the guarantees in June 2012. The derivative portfolio guarantee is currently $13 million and covers Conectiv Energy's performance prior to the assignment. This guarantee will remain in effect until the end of 2015.

[3] Subsidiaries of PHI have guaranteed any residual values in excess of fair value of certain leased equipment and fleet vehicles. As of March 31, 2012, obligations under the guarantees were approximately $14 million. Assets leased under agreements subject to residual value guarantees are typically for periods ranging from 2 years to 10 years. Historically, payments under the guarantees have not been made by the guarantor as, under normal conditions, the contract runs to full term at which time the residual value is immaterial. As such, PHI believes the likelihood of payments being required under the guarantees is remote.