Schedule I - Condensed Financial Information of Parent Company - Related Party Transactions (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Parent Company Only Financial Information [Line Items]
(Payable to) Receivable from Related Party, Total	$ (13)	$ (1)
Money Pool Balance (included in cash and cash equivalents)	65
Conectiv Communication, Inc. [Member]
Parent Company Only Financial Information [Line Items]
(Payable to) Receivable from Related Party, Total	(4)	(4)
PHI Service Company [Member]
Parent Company Only Financial Information [Line Items]
(Payable to) Receivable from Related Party, Total	(10)	3
Other [Member]
Parent Company Only Financial Information [Line Items]
(Payable to) Receivable from Related Party, Total	1
Potomac Capital Investment Corporation (PCI) [Member]
Parent Company Only Financial Information [Line Items]
Potomac Capital Investment Corporation	$ (494)	$ (491)