Commitments And Contingencies (Schedule Of Commitments And Obligations) (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012
Commitments And Contingencies [Line Items]
Energy procurement obligations of Pepco Energy Services	$ 90	[1]
Guarantees associated with disposal of Conectiv Energy assets	13	[2]
Guaranteed lease residual values	17	[3]
Total	120
Derivative portfolio guarantee	13
Obligations under guarantees	54
PHI [Member]
Commitments And Contingencies [Line Items]
Energy procurement obligations of Pepco Energy Services	90	[1]
Guarantees associated with disposal of Conectiv Energy assets	13	[2]
Guaranteed lease residual values	2	[3]
Total	105
Obligations under guarantees	9
Potomac Electric Power Co [Member]
Commitments And Contingencies [Line Items]
Guaranteed lease residual values	5	[3]
Total	5
Obligations under guarantees	15
Delmarva Power & Light Co/De [Member]
Commitments And Contingencies [Line Items]
Guaranteed lease residual values	6	[3]
Total	6
Obligations under guarantees	18
Atlantic City Electric Co [Member]
Commitments And Contingencies [Line Items]
Guaranteed lease residual values	4	[3]
Total	4
Obligations under guarantees	$ 12

[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 $54 million, $9 million of which is a guaranty by PHI, $15 million by Pepco, $18 million by DPL and $12 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.