Schedule I - Condensed Financial Information of Parent (Exelon Corporate) - Basis of Presentation - Narrative (Details) - Exelon Corporate [Member]	Dec. 31, 2019
Schedule of Equity Method Investments [Line Items]
Ownership interest	100.00%
Commonwealth Edison Co [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest	99.00%
Baltimore Gas and Electric Company [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest	100.00%
Preferred Stock [Member] | Baltimore Gas and Electric Company [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest	0.00%