Shareholders' Equity Schedule of Common Stock Warrants (Details) - Commonwealth Edison Co [Member] - shares	Dec. 31, 2019	Dec. 31, 2018
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Outstanding	60,228	60,285
Common Stock [Member]
Class of Warrant or Right [Line Items]
Common Stock Shares Reserved For Warrant Conversion	20,076	20,095