Related Party Transactions - Long Term Debt to Financing Trusts (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Related Party Transaction [Line Items]
Long-term debt to financing trusts	$ 390	$ 390
ComEd Financing Three Affiliate
Related Party Transaction [Line Items]
Long-term debt to financing trusts	206	206
PECO Trust Three Affiliate
Related Party Transaction [Line Items]
Long-term debt to financing trusts	81	81
PECO Trust Four Affiliate
Related Party Transaction [Line Items]
Long-term debt to financing trusts	103	103
Related Party
Related Party Transaction [Line Items]
Long-term debt to financing trusts	390	390
Commonwealth Edison Co | ComEd Financing Three Affiliate
Related Party Transaction [Line Items]
Long-term debt to financing trusts	205	205
Commonwealth Edison Co | PECO Trust Three Affiliate
Related Party Transaction [Line Items]
Long-term debt to financing trusts	0	0
Commonwealth Edison Co | PECO Trust Four Affiliate
Related Party Transaction [Line Items]
Long-term debt to financing trusts	0	0
Commonwealth Edison Co | Related Party
Related Party Transaction [Line Items]
Long-term debt to financing trusts	205	205
PECO Energy Co | ComEd Financing Three Affiliate
Related Party Transaction [Line Items]
Long-term debt to financing trusts	0	0
PECO Energy Co | PECO Trust Three Affiliate
Related Party Transaction [Line Items]
Long-term debt to financing trusts	81	81
PECO Energy Co | PECO Trust Four Affiliate
Related Party Transaction [Line Items]
Long-term debt to financing trusts	103	103
PECO Energy Co | Related Party
Related Party Transaction [Line Items]
Long-term debt to financing trusts	$ 184	$ 184