Commitments And Contingencies (Schedule Of Commitments And Obligations) (Details) (USD $)	12 Months Ended
	Dec. 31, 2011
Energy procurement obligations of Pepco Energy Services	$ 175,000,000	[1]
Guarantees associated with disposal of Conectiv Energy assets	23,000,000	[2]
Guaranteed lease residual values	12,000,000	[3]
Total	210,000,000
Guaranteed amounts on the transferred tolling agreements	10,000,000
Derivative portfolio guarantee	13,000,000
Obligations under guarantees	12,000,000
PHI [Member]
Energy procurement obligations of Pepco Energy Services	175,000,000	[1]
Guarantees associated with disposal of Conectiv Energy assets	23,000,000	[2]
Guaranteed lease residual values	1,000,000	[3]
Total	199,000,000
Potomac Electric Power Co [Member]
Guaranteed lease residual values	3,000,000	[3]
Total	3,000,000
Delmarva Power & Light Co/De [Member]
Guaranteed lease residual values	5,000,000	[3]
Total	5,000,000
Atlantic City Electric Co [Member]
Guaranteed lease residual values	3,000,000	[3]
Total	$ 3,000,000

[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 in connection with transfers of Conectiv Energy's tolling agreements and derivatives portfolio. 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 $10 million at December 31, 2011, which decline until the termination of the guarantees. 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 residual values that could be in excess of fair value of certain equipment and fleet vehicles held through lease agreements. As of December 31, 2011, obligations under the guarantees were approximately $12 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.