Total costs accrued as of the balance sheet date for environmental loss contingencies.

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Commitments And Contingencies (Indian River Oil Release) (Details) (USD $)	0 Months Ended	9 Months Ended		0 Months Ended	3 Months Ended
	Jan. 23, 2011 gal	Sep. 30, 2011	Sep. 30, 2011 Delmarva Power & Light Co/De [Member]	Mar. 26, 2011 Pepco [Member]	Sep. 30, 2011 PHI [Member]
Estimated future response measures			$ 5,000,000
Costs expected to be incurred		1,000,000
Penalty charges related to release of oil in U.S. waters		5,000
Quantity of mineral oil spill	4,500
Civil penalty				40,000
Accrued remediation costs					$ 1,000,000