Debt and Credit Agreements - Commercial Paper Borrowings (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 23, 2022	Feb. 01, 2022	Jan. 31, 2022	Dec. 31, 2021
Commercial Paper
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity	$ 4,000				$ 3,700
Commercial Paper	$ 1,938				$ 599
Average interest rate on commercial paper borrowings	4.77%				0.35%
Revolving Credit Facility [Member]
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity	$ 4,000
Line of credit facility, remaining borrowing capacity	3,992
Corporate, Non-Segment [Member] | Commercial Paper
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity	900				$ 600
Commercial Paper	449				0
Corporate, Non-Segment [Member] | Revolving Credit Facility [Member]
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity	900		$ 900	$ 600
Line of credit facility, remaining borrowing capacity	448
Commonwealth Edison Co [Member] | Commercial Paper
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity	1,000				1,000
Commercial Paper	$ 427				$ 0
Average interest rate on commercial paper borrowings	4.71%				0.00%
Commonwealth Edison Co [Member] | Revolving Credit Facility [Member]
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity	$ 1,000		1,000
Line of credit facility, remaining borrowing capacity	995
PECO Energy Co [Member] | Commercial Paper
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity	600				$ 600
Commercial Paper	$ 239				$ 0
Average interest rate on commercial paper borrowings	4.71%				0.00%
PECO Energy Co [Member] | Revolving Credit Facility [Member]
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity	$ 600		600
Line of credit facility, remaining borrowing capacity	600
Baltimore Gas and Electric Company [Member] | Commercial Paper
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity	600				$ 600
Commercial Paper	$ 409				$ 130
Average interest rate on commercial paper borrowings	4.81%				0.37%
Baltimore Gas and Electric Company [Member] | Revolving Credit Facility [Member]
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity	$ 600		600
Line of credit facility, remaining borrowing capacity	600
Pepco Holdings LLC [Member] | Commercial Paper
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity	900				$ 900
Commercial Paper	$ 414				$ 469
Average interest rate on commercial paper borrowings	4.78%				0.35%
Pepco Holdings LLC [Member] | Revolving Credit Facility [Member]
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity	$ 900
Line of credit facility, remaining borrowing capacity	900
Potomac Electric Power Company [Member] | Commercial Paper
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity	300	$ 400			$ 300
Commercial Paper	$ 299				$ 175
Average interest rate on commercial paper borrowings	4.79%				0.33%
Line of credit facility, remaining borrowing capacity	$ 500
Potomac Electric Power Company [Member] | Revolving Credit Facility [Member]
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity	300		300
Line of credit facility, remaining borrowing capacity	300
Delmarva Power & Light Company [Member] | Commercial Paper
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity	300				$ 300
Commercial Paper	$ 115				$ 149
Average interest rate on commercial paper borrowings	4.76%				0.36%
Line of credit facility, remaining borrowing capacity	$ 500
Delmarva Power & Light Company [Member] | Revolving Credit Facility [Member]
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity	300		300
Line of credit facility, remaining borrowing capacity	300
Atlantic City Electric Company [Member] | Commercial Paper
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity	300	250			$ 300
Commercial Paper	$ 0				$ 145
Average interest rate on commercial paper borrowings	0.00%				0.35%
Line of credit facility, remaining borrowing capacity	$ 350
Atlantic City Electric Company [Member] | Revolving Credit Facility [Member]
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity	300		$ 300
Line of credit facility, remaining borrowing capacity	$ 300
Delmarva Power & Light Co | Commercial Paper
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity		$ 250