Regulatory Matters - Schedule of Completed Rate Cases (Details)																		3 Months Ended	48 Months Ended
	Apr. 18, 2024 USD ($)	Dec. 18, 2023 USD ($)	Dec. 14, 2023 USD ($)	Nov. 30, 2023 USD ($)	Nov. 17, 2023 USD ($)	Sep. 29, 2023 USD ($)	Sep. 27, 2023 USD ($)	Aug. 21, 2023 USD ($)	Apr. 21, 2023 USD ($)	Feb. 17, 2023 USD ($)	Jan. 17, 2023 USD ($)	Dec. 14, 2022 USD ($)	May 19, 2022 USD ($)	Feb. 23, 2022	Feb. 03, 2022	Jun. 28, 2021 USD ($)	Mar. 31, 2021 USD ($)	Mar. 31, 2024 USD ($)	Dec. 31, 2027 USD ($)
Commonwealth Edison Co
Regulatory Matters Completed Rate Cases [Line Items]
Basis points for ComEd's Revenue Requirement															580
Commonwealth Edison Co | Illinois 2023 Electric Distribution Base Rate Case
Regulatory Matters Completed Rate Cases [Line Items]
Requested Revenue Requirement Increase (Decrease)							$ 1,487,000,000				$ 1,487,000,000
Approved Revenue Requirement Increase (Decrease)			$ 501,000,000
Approved Return on Equity, Percentage			8.905%
Commonwealth Edison Co | Illinois 2023 Electric Distribution Base Rate Case | Forecast [Member]
Regulatory Matters Completed Rate Cases [Line Items]
Public Utilities, Approved Debt Capital Structure, Percentage																			50.00%
Commonwealth Edison Co | Illinois 2023 Electric Distribution Base Rate Case | 2023 | Forecast [Member]
Regulatory Matters Completed Rate Cases [Line Items]
Approved Revenue Requirement Increase (Decrease)																			$ 986,000,000
Commonwealth Edison Co | Illinois 2023 Electric Distribution Base Rate Case | 2024
Regulatory Matters Completed Rate Cases [Line Items]
Approved Revenue Requirement Increase (Decrease)			$ 451,000,000
Commonwealth Edison Co | Illinois 2023 Electric Distribution Base Rate Case | 2025
Regulatory Matters Completed Rate Cases [Line Items]
Approved Revenue Requirement Increase (Decrease)			14,000,000
Commonwealth Edison Co | Illinois 2023 Electric Distribution Base Rate Case | 2026
Regulatory Matters Completed Rate Cases [Line Items]
Approved Revenue Requirement Increase (Decrease)			6,000,000
Commonwealth Edison Co | Illinois 2023 Electric Distribution Base Rate Case | 2027
Regulatory Matters Completed Rate Cases [Line Items]
Approved Revenue Requirement Increase (Decrease)			30,000,000
Commonwealth Edison Co | Illinois 2023 Electric Distribution Reconciliation Rate Case
Regulatory Matters Completed Rate Cases [Line Items]
Public Utilities Requested Rate Increase (Decrease), Prior Year Annual Reconciliation									$ 247,000,000
Approved Revenue Requirement Increase (Decrease)				$ 259,000,000
Approved Return on Equity, Percentage				8.91%
Public Utilities, Approved Equity Capital Structure, Percentage				6.48%
Commonwealth Edison Co | Illinois 2023 Electric Distribution Reconciliation Rate Case | 2023
Regulatory Matters Completed Rate Cases [Line Items]
Basis points for ComEd's Revenue Requirement				580
Commonwealth Edison Co | Illinois 2023 Electric Distribution Order on Rehearing
Regulatory Matters Completed Rate Cases [Line Items]
Requested Revenue Requirement Increase (Decrease)											$ 838,000,000
Commonwealth Edison Co | Illinois 2023 Electric Distribution Order on Rehearing | Subsequent Event [Member]
Regulatory Matters Completed Rate Cases [Line Items]
Approved Revenue Requirement Increase (Decrease)	$ 810,000,000
Approved Return on Equity, Percentage	8.905%
Commonwealth Edison Co | Illinois 2023 Electric Distribution Order on Rehearing | 2024 | Subsequent Event [Member]
Regulatory Matters Completed Rate Cases [Line Items]
Approved Revenue Requirement Increase (Decrease)	$ 150,000,000
Commonwealth Edison Co | Illinois 2023 Electric Distribution Order on Rehearing | 2025 | Subsequent Event [Member]
Regulatory Matters Completed Rate Cases [Line Items]
Approved Revenue Requirement Increase (Decrease)	186,000,000
Commonwealth Edison Co | Illinois 2023 Electric Distribution Order on Rehearing | 2026 | Subsequent Event [Member]
Regulatory Matters Completed Rate Cases [Line Items]
Approved Revenue Requirement Increase (Decrease)	221,000,000
Commonwealth Edison Co | Illinois 2023 Electric Distribution Order on Rehearing | 2027 | Subsequent Event [Member]
Regulatory Matters Completed Rate Cases [Line Items]
Approved Revenue Requirement Increase (Decrease)	253,000,000
Baltimore Gas and Electric Company | Maryland 2023 Electric Distribution Base Rate Case
Regulatory Matters Completed Rate Cases [Line Items]
Requested Revenue Requirement Increase (Decrease)										$ 313,000,000
Approved Revenue Requirement Increase (Decrease)			$ 179,000,000
Approved Return on Equity, Percentage			9.50%
Baltimore Gas and Electric Company | Maryland 2023 Electric Distribution Base Rate Case | 2024
Regulatory Matters Completed Rate Cases [Line Items]
Approved Revenue Requirement Increase (Decrease)		$ 41,000,000
Baltimore Gas and Electric Company | Maryland 2023 Electric Distribution Base Rate Case | 2025
Regulatory Matters Completed Rate Cases [Line Items]
Approved Revenue Requirement Increase (Decrease)		113,000,000
Baltimore Gas and Electric Company | Maryland 2023 Electric Distribution Base Rate Case | 2026
Regulatory Matters Completed Rate Cases [Line Items]
Approved Revenue Requirement Increase (Decrease)		25,000,000
Baltimore Gas and Electric Company | Maryland 2023 Gas Distribution Base Rate Case
Regulatory Matters Completed Rate Cases [Line Items]
Requested Revenue Requirement Increase (Decrease)										$ 289,000,000
Approved Revenue Requirement Increase (Decrease)			$ 229,000,000
Approved Return on Equity, Percentage			9.45%
Baltimore Gas and Electric Company | Maryland 2023 Gas Distribution Base Rate Case | 2024
Regulatory Matters Completed Rate Cases [Line Items]
Approved Revenue Requirement Increase (Decrease)		126,000,000
Baltimore Gas and Electric Company | Maryland 2023 Gas Distribution Base Rate Case | 2025
Regulatory Matters Completed Rate Cases [Line Items]
Approved Revenue Requirement Increase (Decrease)		62,000,000
Baltimore Gas and Electric Company | Maryland 2023 Gas Distribution Base Rate Case | 2026
Regulatory Matters Completed Rate Cases [Line Items]
Approved Revenue Requirement Increase (Decrease)		$ 41,000,000
Baltimore Gas and Electric Company | Maryland 2023 Electric Distribution Reconciliation Rate Case | 2021
Regulatory Matters Completed Rate Cases [Line Items]
Approved Revenue Requirement Increase (Decrease)																		$ 13,000,000
Baltimore Gas and Electric Company | Maryland 2023 Electric Distribution Reconciliation Rate Case | 2022
Regulatory Matters Completed Rate Cases [Line Items]
Approved Revenue Requirement Increase (Decrease)																		39,000,000
Baltimore Gas and Electric Company | Maryland 2023 Electric Distribution Reconciliation Rate Case | 2023
Regulatory Matters Completed Rate Cases [Line Items]
Approved Revenue Requirement Increase (Decrease)																		79,000,000
Baltimore Gas and Electric Company | Maryland 2023 Gas Distribution Reconciliation Rate Case | 2021
Regulatory Matters Completed Rate Cases [Line Items]
Approved Revenue Requirement Increase (Decrease)																		7,000,000
Baltimore Gas and Electric Company | Maryland 2023 Gas Distribution Reconciliation Rate Case | 2022
Regulatory Matters Completed Rate Cases [Line Items]
Approved Revenue Requirement Increase (Decrease)																		15,000,000
Baltimore Gas and Electric Company | Maryland 2023 Gas Distribution Reconciliation Rate Case | 2023
Regulatory Matters Completed Rate Cases [Line Items]
Approved Revenue Requirement Increase (Decrease)																		$ 73,000,000
Potomac Electric Power Company | Maryland 2020 Electric Distribution Base Rate Case [Member]
Regulatory Matters Completed Rate Cases [Line Items]
Public Utilities, Requested Rate Increase (Decrease), Amended, Amount																	$ 104,000,000
Approved Revenue Requirement Increase (Decrease)																$ 52,000,000
Approved Return on Equity, Percentage																9.55%
Potomac Electric Power Company | Maryland 2020 Electric Distribution Base Rate Case [Member] | 2022
Regulatory Matters Completed Rate Cases [Line Items]
Approved Revenue Requirement Increase (Decrease)																$ 21,000,000
Potomac Electric Power Company | Maryland 2020 Electric Distribution Base Rate Case [Member] | 2023
Regulatory Matters Completed Rate Cases [Line Items]
Approved Revenue Requirement Increase (Decrease)																16,000,000
Potomac Electric Power Company | Maryland 2020 Electric Distribution Base Rate Case [Member] | 2024
Regulatory Matters Completed Rate Cases [Line Items]
Approved Revenue Requirement Increase (Decrease)																$ 15,000,000
Potomac Electric Power Company | Maryland 2020 Electric Distribution Base Rate Case [Member] | Offsets | 2022
Regulatory Matters Completed Rate Cases [Line Items]
Public Utilities, Approved Rate Increase (Decrease), Percentage														25.00%
Delmarva Power and Light Company | Maryland 2022 Electric Distribution Base Rate Case
Regulatory Matters Completed Rate Cases [Line Items]
Requested Revenue Requirement Increase (Decrease)													$ 38,000,000
Approved Revenue Requirement Increase (Decrease)												$ 29,000,000
Approved Return on Equity, Percentage												9.60%
Delmarva Power and Light Company | Maryland 2022 Electric Distribution Base Rate Case | 2023
Regulatory Matters Completed Rate Cases [Line Items]
Approved Revenue Requirement Increase (Decrease)												$ 17,000,000
Delmarva Power and Light Company | Maryland 2022 Electric Distribution Base Rate Case | 2024
Regulatory Matters Completed Rate Cases [Line Items]
Approved Revenue Requirement Increase (Decrease)												6,000,000
Delmarva Power and Light Company | Maryland 2022 Electric Distribution Base Rate Case | 2025
Regulatory Matters Completed Rate Cases [Line Items]
Approved Revenue Requirement Increase (Decrease)												$ 6,000,000
Delmarva Power and Light Company | Delaware 2022 Electric Distribution Base Rate Case
Regulatory Matters Completed Rate Cases [Line Items]
Public Utilities, Requested Rate Increase (Decrease), Amended, Amount						$ 39,000,000
Delmarva Power and Light Company | Delaware 2022 Electric Distribution Base Rate Case | Subsequent Event [Member]
Regulatory Matters Completed Rate Cases [Line Items]
Approved Revenue Requirement Increase (Decrease)	$ 28,000,000
Approved Return on Equity, Percentage	9.60%
Atlantic City Electric Company | New Jersey 2023 Electric Distribution Base Rate Case
Regulatory Matters Completed Rate Cases [Line Items]
Public Utilities, Requested Rate Increase (Decrease), Amended, Amount								$ 92,000,000
Approved Revenue Requirement Increase (Decrease)					$ 45,000,000
Approved Return on Equity, Percentage					9.60%
Atlantic City Electric Company | New Jersey 2023 Electric Distribution Base Rate Case | 2023
Regulatory Matters Completed Rate Cases [Line Items]
Approved Revenue Requirement Increase (Decrease)					$ 36,000,000
Atlantic City Electric Company | New Jersey 2023 Electric Distribution Base Rate Case | 2024
Regulatory Matters Completed Rate Cases [Line Items]
Approved Revenue Requirement Increase (Decrease)					$ 9,000,000