Leases - Lessor - Types of Leases (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Lessor, Lease, Description [Line Items]
Operating lease income	$ 5	$ 4	$ 5
Minimum
Lessor, Lease, Description [Line Items]
Remaining lease terms, Lessor, Operating Lease	1 year
Options to extend the term, Lessor, Operating Lease	1 years
Maximum
Lessor, Lease, Description [Line Items]
Remaining lease terms, Lessor, Operating Lease	79 years
Options to extend the term, Lessor, Operating Lease	79 years
Real Estate
Lessor, Lease, Description [Line Items]
Lessor, Operating Lease, Description	●
Commonwealth Edison Co
Lessor, Lease, Description [Line Items]
Operating lease income	$ 0	0	0
Commonwealth Edison Co | Minimum
Lessor, Lease, Description [Line Items]
Remaining lease terms, Lessor, Operating Lease	1 year
Options to extend the term, Lessor, Operating Lease	5 years
Commonwealth Edison Co | Maximum
Lessor, Lease, Description [Line Items]
Remaining lease terms, Lessor, Operating Lease	13 years
Options to extend the term, Lessor, Operating Lease	79 years
Commonwealth Edison Co | Real Estate
Lessor, Lease, Description [Line Items]
Lessor, Operating Lease, Description	●
PECO Energy Co
Lessor, Lease, Description [Line Items]
Operating lease income	$ 0	0	0
PECO Energy Co | Minimum
Lessor, Lease, Description [Line Items]
Remaining lease terms, Lessor, Operating Lease	1 year
Options to extend the term, Lessor, Operating Lease	1 years
PECO Energy Co | Maximum
Lessor, Lease, Description [Line Items]
Remaining lease terms, Lessor, Operating Lease	79 years
Options to extend the term, Lessor, Operating Lease	50 years
PECO Energy Co | Real Estate
Lessor, Lease, Description [Line Items]
Lessor, Operating Lease, Description	●
Baltimore Gas and Electric Company
Lessor, Lease, Description [Line Items]
Operating lease income	$ 0	0	0
Baltimore Gas and Electric Company | Minimum
Lessor, Lease, Description [Line Items]
Remaining lease terms, Lessor, Operating Lease	19 years
Baltimore Gas and Electric Company | Maximum
Lessor, Lease, Description [Line Items]
Remaining lease terms, Lessor, Operating Lease	19 years
Baltimore Gas and Electric Company | Real Estate
Lessor, Lease, Description [Line Items]
Lessor, Operating Lease, Description	●
Pepco Holdings LLC
Lessor, Lease, Description [Line Items]
Operating lease income	$ 4	4	4
Pepco Holdings LLC | Minimum
Lessor, Lease, Description [Line Items]
Remaining lease terms, Lessor, Operating Lease	1 year
Options to extend the term, Lessor, Operating Lease	N/A years
Pepco Holdings LLC | Maximum
Lessor, Lease, Description [Line Items]
Remaining lease terms, Lessor, Operating Lease	9 years
Options to extend the term, Lessor, Operating Lease	N/A years
Pepco Holdings LLC | Real Estate
Lessor, Lease, Description [Line Items]
Lessor, Operating Lease, Description	●
Potomac Electric Power Company
Lessor, Lease, Description [Line Items]
Operating lease income	$ 0	0	0
Potomac Electric Power Company | Minimum
Lessor, Lease, Description [Line Items]
Remaining lease terms, Lessor, Operating Lease	1 year
Potomac Electric Power Company | Maximum
Lessor, Lease, Description [Line Items]
Remaining lease terms, Lessor, Operating Lease	2 years
Potomac Electric Power Company | Real Estate
Lessor, Lease, Description [Line Items]
Lessor, Operating Lease, Description	●
Delmarva Power & Light Company
Lessor, Lease, Description [Line Items]
Operating lease income	$ 3	3	3
Delmarva Power & Light Company | Minimum
Lessor, Lease, Description [Line Items]
Remaining lease terms, Lessor, Operating Lease	8 years
Delmarva Power & Light Company | Maximum
Lessor, Lease, Description [Line Items]
Remaining lease terms, Lessor, Operating Lease	9 years
Delmarva Power & Light Company | Real Estate
Lessor, Lease, Description [Line Items]
Lessor, Operating Lease, Description	●
Atlantic City Electric Company | Real Estate
Lessor, Lease, Description [Line Items]
Operating lease income	$ 0	$ 0	$ 0