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