Shareholder Equity Schedule of Common Stock Authorized and Outstanding (Details) - $ / shares	Dec. 31, 2016	Dec. 31, 2015
Class of Stock [Line Items]
Common stock, shares authorized	2,000,000,000	2,000,000,000
Common Stock, Shares, Outstanding	924,035,059	919,924,742
Commonwealth Edison Co [Member]
Class of Stock [Line Items]
Common Stock, Par or Stated Value Per Share	$ 12.50
Common stock, shares authorized	250,000,000
Common Stock, Shares, Outstanding	127,017,157	127,016,973
PECO Energy Co [Member]
Class of Stock [Line Items]
Common stock, shares authorized	500,000,000
Common Stock, Shares, Outstanding	170,478,507	170,478,507
Baltimore Gas and Electric Company [Member]
Class of Stock [Line Items]
Common stock, shares authorized	175,000,000
Common Stock, Shares, Outstanding	1,000	1,000
Pepco Holdings LLC [Member] | Predecessor [Member]
Class of Stock [Line Items]
Common Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Common stock, shares authorized	400,000,000	400,000,000.00
Common Stock, Shares, Outstanding		254,289,261.00
Potomac Electric Power Company [Member]
Class of Stock [Line Items]
Common Stock, Par or Stated Value Per Share	$ 0.01
Common stock, shares authorized	200,000,000
Common Stock, Shares, Outstanding	100	100
Delmarva Power and Light Company [Member]
Class of Stock [Line Items]
Common Stock, Par or Stated Value Per Share	$ 2.25
Common stock, shares authorized	1,000
Common Stock, Shares, Outstanding	1,000	1,000
Atlantic City Electric Company [Member]
Class of Stock [Line Items]
Common Stock, Par or Stated Value Per Share	$ 3.00
Common stock, shares authorized	25,000,000
Common Stock, Shares, Outstanding	8,546,017	8,546,017