Regulatory Matters- Narrative (Details) - USD ($)	7 Months Ended	12 Months Ended				36 Months Ended	48 Months Ended		60 Months Ended	72 Months Ended
	Dec. 31, 2017	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2024	Jun. 30, 2023	Dec. 31, 2022	Dec. 31, 2023	Jul. 10, 2023	Aug. 26, 2020	Jul. 21, 2017
Commonwealth Edison Co [Member]
Regulatory Matters Additional Narrative Information [Line Items]
Purchase Obligation												$ 170,000,000
Atlantic City Electric Company [Member]
Regulatory Matters Additional Narrative Information [Line Items]
Proposed Capital Expenditure											$ 220,000,000
Maximum [Member] | Exelon Generation Co L L C [Member]
Regulatory Matters Additional Narrative Information [Line Items]
Purchase Obligation				$ 14,000,000
Minimum [Member] | Exelon Generation Co L L C [Member]
Regulatory Matters Additional Narrative Information [Line Items]
Purchase Obligation				11,000,000
Illinois Utilities [Member]
Regulatory Matters Additional Narrative Information [Line Items]
Purchase Obligation												$ 235,000,000
Energy Commodities and Service [Member]
Regulatory Matters Additional Narrative Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		$ 16,400,000,000	$ 17,754,000,000	19,168,000,000
Energy Commodities and Service [Member] | Exelon Generation Co L L C [Member]
Regulatory Matters Additional Narrative Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		16,392,000,000	17,752,000,000	$ 19,169,000,000
Zero Emission Standard [Member] | Energy Commodities and Service [Member] | Exelon Generation Co L L C [Member]
Regulatory Matters Additional Narrative Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	$ 150,000,000
Clean Energy Legislation [Member] | Exelon Generation Co L L C [Member]
Regulatory Matters Additional Narrative Information [Line Items]
Competitive businesses other revenues		69,000,000	$ 53,000,000
Conowingo [Member] | Exelon Generation Co L L C [Member]
Regulatory Matters Additional Narrative Information [Line Items]
Environmental Costs Recognized, Capitalized		45,000,000
Forecast [Member] | Baltimore Gas and Electric Company [Member]
Regulatory Matters Additional Narrative Information [Line Items]
Proposed Capital Expenditure									$ 732,000,000
Payments to Acquire Property, Plant, and Equipment									$ 200,000,000
Forecast [Member] | Potomac Electric Power Company [Member]
Regulatory Matters Additional Narrative Information [Line Items]
Proposed Capital Expenditure		$ 30,000,000				$ 70,000,000				$ 500,000,000
Forecast [Member] | Atlantic City Electric Company [Member]
Regulatory Matters Additional Narrative Information [Line Items]
Proposed Capital Expenditure								$ 338,000,000
Payments to Acquire Property, Plant, and Equipment							$ 96,000,000
ILLINOIS | Exelon Generation Co L L C [Member]
Regulatory Matters Additional Narrative Information [Line Items]
exc_ZECChargeperMWh					$ 16.50