Debt and Credit Agreements - Summary of Bank Commitments, Credit Facility Borrowings and Available Capacity (Details) - Revolving Credit Facility [Member] - USD ($) $ in Millions	Dec. 31, 2022	Feb. 01, 2022	Jan. 31, 2022
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity	$ 4,000
Long-term line of credit/facility draws	0
Outstanding letters of credit	8
Actual available capacity	3,992
To support additional commercial paper	2,054
Corporate, Non-Segment [Member]
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity	900	$ 900	$ 600
Outstanding letters of credit	3
Actual available capacity	448
Commonwealth Edison Co [Member]
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity	1,000	1,000
Long-term line of credit/facility draws	0
Outstanding letters of credit	5
Actual available capacity	995
To support additional commercial paper	568
PECO Energy Co [Member]
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity	600	600
Long-term line of credit/facility draws	0
Outstanding letters of credit	0
Actual available capacity	600
To support additional commercial paper	361
Baltimore Gas and Electric Company [Member]
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity	600	600
Long-term line of credit/facility draws	0
Outstanding letters of credit	0
Actual available capacity	600
To support additional commercial paper	191
Pepco Holdings LLC [Member]
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity	900
Long-term line of credit/facility draws	0
Outstanding letters of credit	0
Actual available capacity	900
To support additional commercial paper	486
Potomac Electric Power Company [Member]
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity	300	300
Long-term line of credit/facility draws	0
Outstanding letters of credit	0
Actual available capacity	300
To support additional commercial paper	1
Delmarva Power & Light Company [Member]
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity	300	300
Long-term line of credit/facility draws	0
Outstanding letters of credit	0
Actual available capacity	300
To support additional commercial paper	185
Atlantic City Electric Company [Member]
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity	300	$ 300
Long-term line of credit/facility draws	0
Outstanding letters of credit	0
Actual available capacity	300
To support additional commercial paper	$ 300