Stock-Based Compensation, Dividend Restrictions, And Calculations Of Earnings Per Share Of Common Stock (Common Stock Reserved And Unissued) (Details)	Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares	14,421,629
DRP [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares	3,448,048
Conectiv Incentive Compensation Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares	1,093,701	[1]
Potomac Electric Power Company Long-Term Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares	327,059	[1]
Pepco Holdings Long-Term Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares	7,791,543
Pepco Holdings Non-Management Directors Compensation Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares	462,429
Pepco Holdings Retirement Savings Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares	1,298,849

[1] No further awards will be made under this plan.