Derivative Instruments And Hedging Activities (Cash Flow Hedges Included In Accumulated Other Comprehensive Loss) (Details) (USD $) In Millions	9 Months Ended
	Sep. 30, 2011		Sep. 30, 2010
Accumulated Other Comprehensive Loss After-tax	$ 50	[1]	$ 113	[2]
Portion Expected to be Reclassified to Income during the Next 12 Months	29		64
Minimum pension liability included in AOCL	21		15
Energy Commodity [Member]
Accumulated Other Comprehensive Loss After-tax	40	[1],[3]	102	[2],[4]
Portion Expected to be Reclassified to Income during the Next 12 Months	28	[3]	63	[4]
Maximum Term	32 months	[3]	44 months	[4]
Interest Rate [Member]
Accumulated Other Comprehensive Loss After-tax	10	[1]	11	[2]
Portion Expected to be Reclassified to Income during the Next 12 Months	1		1
Maximum Term	251 months		263 months
Conectiv Energy [Member]
Minimum pension liability included in AOCL related to discontinued operations	$ 20

[1] AOCL on PHI's Consolidated Balance Sheet as of September 30, 2011, includes a $21 million balance related to minimum pension liability. This balance is not included in this table as the minimum pension liability is not a cash flow hedge.

[2] AOCL on PHI's Consolidated Balance Sheet as of September 30, 2010, includes a $15 million balance related to minimum pension liability and a $20 million balance related to Conectiv Energy. These balances are not included in this table as the minimum pension liability is not a cash flow hedge and Conectiv Energy is reported as a discontinued operation.

[3] The unrealized energy commodity derivative losses recorded in AOCL are largely offset by forecasted natural gas and electricity physical purchases for delivery to retail customers that are in gain positions and subject to accrual accounting. These forward purchase contracts are exempted from mark-to-market accounting because they either qualify as normal purchases under FASB guidance on derivatives and hedging or they are not derivative contracts. Under accrual accounting, no asset is recorded on the balance sheet for these contracts, and the purchase cost is not recognized until the period of distribution.

[4] The unrealized derivative losses recorded in AOCL are largely offset by forecasted natural gas and electricity physical purchases for delivery to retail customers that are in gain positions and subject to accrual accounting. These forward purchase contracts are exempted from mark-to-market accounting because they either qualify as normal purchases under FASB guidance on derivatives and hedging or they are not derivative contracts. Under accrual accounting, no asset is recorded on the balance sheet for these contracts, and the purchase cost is not recognized until the period of distribution.