Related Party Transactions - Long Term Debt to Financing Trusts (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Related Party Transaction [Line Items]
Long-term debt to financing trust	$ 390	$ 390
ComEd Financing Three Affiliate [Member]
Related Party Transaction [Line Items]
Long-term debt to financing trust	206	206
PECO Trust Three Affiliate [Member]
Related Party Transaction [Line Items]
Long-term debt to financing trust	81	81
PECO Trust Four Affiliate [Member]
Related Party Transaction [Line Items]
Long-term debt to financing trust	103	103
Commonwealth Edison Co [Member]
Related Party Transaction [Line Items]
Long-term debt to financing trust	205	205
Commonwealth Edison Co [Member] | ComEd Financing Three Affiliate [Member]
Related Party Transaction [Line Items]
Long-term debt to financing trust	205	205
Commonwealth Edison Co [Member] | PECO Trust Three Affiliate [Member]
Related Party Transaction [Line Items]
Long-term debt to financing trust	0	0
Commonwealth Edison Co [Member] | PECO Trust Four Affiliate [Member]
Related Party Transaction [Line Items]
Long-term debt to financing trust	0	0
PECO Energy Co [Member]
Related Party Transaction [Line Items]
Long-term debt to financing trust	184	184
PECO Energy Co [Member] | ComEd Financing Three Affiliate [Member]
Related Party Transaction [Line Items]
Long-term debt to financing trust	0	0
PECO Energy Co [Member] | PECO Trust Three Affiliate [Member]
Related Party Transaction [Line Items]
Long-term debt to financing trust	81	81
PECO Energy Co [Member] | PECO Trust Four Affiliate [Member]
Related Party Transaction [Line Items]
Long-term debt to financing trust	$ 103	$ 103