Commitments And Contingencies (Schedule Of Commitments And Obligations) (Detail) (USD $)	9 Months Ended
	Sep. 30, 2012
Commitments And Contingencies [Line Items]
GuaranteesEnergyProcurementObligations	$ 101	[1]
Guarantees associated with disposal of Conectiv Energy assets	13	[2]
Guaranteed lease residual values	16	[3]
Total	130
Derivative portfolio guarantee	13,000,000
Obligations under guarantees	52,000,000
Maximum [Member]
Commitments And Contingencies [Line Items]
Lease term range	3 to 8 years
Minimum [Member]
Commitments And Contingencies [Line Items]
Lease term range	1 to 4 years
Pepco Holdings Inc [Member]
Commitments And Contingencies [Line Items]
GuaranteesEnergyProcurementObligations	101	[1]
Guarantees associated with disposal of Conectiv Energy assets	13	[2]
Guaranteed lease residual values	2	[3]
Total	116
Obligations under guarantees	10,000,000
Potomac Electric Power Co [Member]
Commitments And Contingencies [Line Items]
Guaranteed lease residual values	4	[3]
Total	4
Obligations under guarantees	14,000,000
Delmarva Power & Light Co/De [Member]
Commitments And Contingencies [Line Items]
Guaranteed lease residual values	6	[3]
Total	6
Obligations under guarantees	17,000,000
Atlantic City Electric Co [Member]
Commitments And Contingencies [Line Items]
Guaranteed lease residual values	4	[3]
Total	4
Obligations under guarantees	$ 11,000,000

[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 of Conectiv Energy's derivatives portfolio transferred in connection with the disposition of Conectiv Energy's wholesale business. 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] Represents the maximum potential obligation in the event that the fair value of certain leased equipment and fleet vehicles is zero at the end of the maximum lease term. The maximum lease term associated with these assets ranges from 3 to 8 years. The maximum potential obligation at the end of the minimum lease term would be $52 million, $10 million of which is a guaranty by PHI, $14 million by Pepco, $17 million by DPL and $11 million by ACE. The minimum lease term associated with these assets ranges from 1 to 4 years. Historically, payments under the guarantees have not been made and PHI believes the likelihood of payments being required under the guarantees is remote.