Debt and Credit Agreements - Summary of Interest Coverage Ratios (Details)	12 Months Ended
	Dec. 31, 2018
Debt Instrument [Line Items]
Debt Instrument, Covenant Compliance	7.34
Exelon Generation Co L L C [Member]
Debt Instrument [Line Items]
Debt Instrument, Covenant Compliance	10.99
Commonwealth Edison Co [Member]
Debt Instrument [Line Items]
Debt Instrument, Covenant Compliance	7.34
PECO Energy Co [Member]
Debt Instrument [Line Items]
Debt Instrument, Covenant Compliance	8.14
Baltimore Gas and Electric Company [Member]
Debt Instrument [Line Items]
Debt Instrument, Covenant Compliance	9.77
Potomac Electric Power Company [Member]
Debt Instrument [Line Items]
Debt Instrument, Covenant Compliance	5.98
Delmarva Power & Light Company [Member]
Debt Instrument [Line Items]
Debt Instrument, Covenant Compliance	7.03
Atlantic City Electric Company [Member]
Debt Instrument [Line Items]
Debt Instrument, Covenant Compliance	5.06