Regulatory Matters - Annual Electric Transmission Fillings (Details) - USD ($) $ in Millions		Mar. 13, 2019	Jan. 04, 2019	Nov. 19, 2018	Jun. 08, 2018
Baltimore Gas and Electric Company [Member] | Gas Distribution [Member]
Public Utilities, General Disclosures [Line Items]
Initial revenue requirement (decrease) increase					$ 61
Public Utilities, Requested Rate Increase (Decrease), Amended, Amount			$ 43
Public Utilities, Requested Return on Equity, Percentage			9.80%
Atlantic City Electric Company [Member] | Electric Distribution [Member]
Public Utilities, General Disclosures [Line Items]
Initial revenue requirement (decrease) increase	[1]			$ 122
Public Utilities, Requested Rate Increase (Decrease), Amended, Amount	[1]	$ 70
Public Utilities, Requested Return on Equity, Percentage		9.60%

[1] Requested and approved increases are before New Jersey sales and use tax