Debt and Credit Agreements - Commercial Paper Borrowings (Details) - USD ($) $ in Millions	Jan. 31, 2025	Dec. 31, 2024	Aug. 29, 2024	Dec. 31, 2023
Commercial Paper
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity		$ 4,000		$ 4,000
Commercial paper		$ 1,359		$ 1,624
Average interest rate on commercial paper borrowings		4.66%		5.58%
Revolving Credit Facility
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity		$ 4,000	$ 900
Line of credit facility, remaining borrowing capacity		3,951
Corporate, Non-Segment | Commercial Paper
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity		900		$ 900
Commercial paper		426		527
Corporate, Non-Segment | Revolving Credit Facility
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity		900	900
Line of credit facility, remaining borrowing capacity		471
Commonwealth Edison Co | Commercial Paper
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity		1,000		1,000
Commercial paper		$ 36		$ 202
Average interest rate on commercial paper borrowings		4.55%		5.53%
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		985
PECO Energy Co | Commercial Paper
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity		600		$ 600
Commercial paper		$ 192		$ 165
Average interest rate on commercial paper borrowings		4.65%		5.57%
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		596
Baltimore Gas and Electric Company | Commercial Paper
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity		600		$ 600
Commercial paper		$ 175		$ 336
Average interest rate on commercial paper borrowings		4.61%		5.59%
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		575
Pepco Holdings LLC | Commercial Paper
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity		900		$ 900
Commercial paper		$ 530		$ 394
Average interest rate on commercial paper borrowings		4.70%		5.60%
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		898
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		$ 200		$ 132
Average interest rate on commercial paper borrowings		4.69%		5.59%
Line of credit facility, remaining borrowing capacity		$ 500
Potomac Electric Power Company | Commercial Paper | Subsequent Event
Short-term Debt [Line Items]
Line of credit facility, remaining borrowing capacity	340
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		298
Delmarva Power & Light Company | Commercial Paper
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity		300		$ 300
Commercial paper		$ 144		$ 63
Average interest rate on commercial paper borrowings		4.74%		5.60%
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	$ 260
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		$ 186		$ 199
Average interest rate on commercial paper borrowings		4.67%		5.60%
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