Commitments And Contingencies (Schedule Of Commitments And Obligations) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013
Commitments And Contingencies [Line Items]
Energy procurement obligations of Pepco Energy Services	$ 75	[1]
Guarantees associated with disposal of Conectiv Energy assets	13	[2]
Guaranteed lease residual values	18	[3]
Total	106
Derivative portfolio guarantee	13
Obligations under guarantee	55
Minimum [Member]
Commitments And Contingencies [Line Items]
Lease term range	1 to 4 years
Maximum [Member]
Commitments And Contingencies [Line Items]
Lease term range	3 to 8 years
PHI [Member]
Commitments And Contingencies [Line Items]
Energy procurement obligations of Pepco Energy Services	75	[1]
Guarantees associated with disposal of Conectiv Energy assets	13	[2]
Guaranteed lease residual values	2	[3]
Total	90
Obligations under guarantee	8
Potomac Electric Power Co [Member]
Commitments And Contingencies [Line Items]
Energy procurement obligations of Pepco Energy Services		[1]
Guarantees associated with disposal of Conectiv Energy assets		[2]
Guaranteed lease residual values	5	[3]
Total	5
Obligations under guarantee	15
Delmarva Power & Light Co/De [Member]
Commitments And Contingencies [Line Items]
Energy procurement obligations of Pepco Energy Services		[1]
Guarantees associated with disposal of Conectiv Energy assets		[2]
Guaranteed lease residual values	7	[3]
Total	7
Obligations under guarantee	19
Atlantic City Electric Co [Member]
Commitments And Contingencies [Line Items]
Energy procurement obligations of Pepco Energy Services		[1]
Guarantees associated with disposal of Conectiv Energy assets		[2]
Guaranteed lease residual values	4	[3]
Total	4
Obligations under guarantee	$ 13

[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 $55 million, $8 million of which is a guaranty by PHI, $15 million by Pepco, $19 million by DPL and $13 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.