Debt and Credit Agreements - Commercial Paper Borrowings (Details) - USD ($) $ in Millions	Jan. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Feb. 01, 2022	Jan. 31, 2022
Commercial Paper
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity		$ 4,000	$ 4,000
Commercial paper		$ 1,624	$ 1,938
Average interest rate on commercial paper borrowings		5.58%	4.77%
Revolving Credit Facility
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity		$ 4,000
Line of credit facility, remaining borrowing capacity		3,981
Corporate, Non-Segment | Commercial Paper
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity		900	$ 900
Commercial paper		527	449
Corporate, Non-Segment | Revolving Credit Facility
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity		900		$ 900	$ 600
Line of credit facility, remaining borrowing capacity		370
Commonwealth Edison Co | Commercial Paper
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity		1,000	1,000
Commercial paper		$ 202	$ 427
Average interest rate on commercial paper borrowings		5.53%	4.71%
Commonwealth Edison Co | Revolving Credit Facility
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity		$ 1,000		1,000
Line of credit facility, remaining borrowing capacity		990
PECO Energy Co | Commercial Paper
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity		600	$ 600
Commercial paper		$ 165	$ 239
Average interest rate on commercial paper borrowings		5.57%	4.71%
PECO Energy Co | Revolving Credit Facility
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 | Commercial Paper
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity		600	$ 600
Commercial paper		$ 336	$ 409
Average interest rate on commercial paper borrowings		5.59%	4.81%
Baltimore Gas and Electric Company | Revolving Credit Facility
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity		$ 600		600
Line of credit facility, remaining borrowing capacity		594
Pepco Holdings LLC | Commercial Paper
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity		900	$ 900
Commercial paper		$ 394	$ 414
Average interest rate on commercial paper borrowings		5.60%	4.78%
Pepco Holdings LLC | Revolving Credit Facility
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity		$ 900
Line of credit facility, remaining borrowing capacity		900
Pepco Holdings LLC | Revolving Credit Facility | Subsequent Event
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity	$ 900
Potomac Electric Power Company | Commercial Paper
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity		300	$ 300
Commercial paper		$ 132	$ 299
Average interest rate on commercial paper borrowings		5.59%	4.79%
Line of credit facility, remaining borrowing capacity		$ 500
Potomac Electric Power Company | Revolving Credit Facility
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 | Commercial Paper
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity		300	$ 300
Commercial paper		$ 63	$ 115
Average interest rate on commercial paper borrowings		5.60%	4.76%
Line of credit facility, remaining borrowing capacity		$ 500
Delmarva Power & Light Company | Commercial Paper | Subsequent Event
Short-term Debt [Line Items]
Line of credit facility, remaining borrowing capacity	250
Delmarva Power & Light Company | Revolving Credit Facility
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 | Commercial Paper
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity		300	$ 300
Commercial paper		$ 199	$ 0
Average interest rate on commercial paper borrowings		5.60%	0.00%
Line of credit facility, remaining borrowing capacity		$ 350
Atlantic City Electric Company | Commercial Paper | Subsequent Event
Short-term Debt [Line Items]
Line of credit facility, remaining borrowing capacity	$ 350
Atlantic City Electric Company | Revolving Credit Facility
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity		300		$ 300
Line of credit facility, remaining borrowing capacity		$ 300