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Capacity of facility of company owned solar distribution generation facilities.

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Amount of consideration received or receivable for the disposal of assets and liabilities, including discontinued operation.

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For an unclassified balance sheet, amount of receivables due from an entity that is affiliated with the reporting entity by means of direct or indirect ownership.

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The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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Amount of gain (loss) from the difference between the sale price or salvage price and the book value of an asset that was sold or retired, and gain (loss) from the write down of assets from their carrying value to fair value.

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The aggregate amount of write-downs for impairments recognized during the period for long-lived assets held for abandonment, exchange or sale.

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The equity interest of noncontrolling shareholders, partners or other equity holders in consolidated entity.

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Mergers, Acquisitions, and Dispositions - Narrative (Details) $ in Millions		6 Months Ended
	Apr. 01, 2014 USD ($)	Jun. 30, 2021 USD ($) MW	Jun. 30, 2020 USD ($)	Dec. 31, 2020
Business Dispositions
Gain (Loss) on Sale of Assets and Asset Impairment Charges		$ 83	$ 13
CENG [Member]
Business Acquisitions
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners		49.99%
Solar Business
Business Dispositions
Capacity Of Facility Of Company Owned Solar Distribution Generation Facilities \| MW		360
Disposal Group, Including Discontinued Operation, Consideration		$ 810
Proceeds from Divestiture of Businesses		675
Disposal Group, Including Discontinued Operation, Liabilities, Noncurrent		125
Gain (Loss) on Sale of Assets and Asset Impairment Charges		68
Albany Green Energy biomass facility
Business Dispositions
Disposal Group, Including Discontinued Operation, Consideration		36
Impairment of Long-Lived Assets to be Disposed of		140
Exelon Generation Co L L C [Member]
Business Dispositions
Gain (Loss) on Sale of Assets and Asset Impairment Charges		$ 79	$ 12
Exelon Generation Co L L C [Member] \| CENG [Member]
Business Acquisitions
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners		49.99%
Exelon Generation Co L L C [Member] \| Solar Business
Business Dispositions
Capacity Of Facility Of Company Owned Solar Distribution Generation Facilities \| MW		360
Disposal Group, Including Discontinued Operation, Consideration		$ 810
Proceeds from Divestiture of Businesses		675
Disposal Group, Including Discontinued Operation, Liabilities, Noncurrent		125
Gain (Loss) on Sale of Assets and Asset Impairment Charges		68
Exelon Generation Co L L C [Member] \| Albany Green Energy biomass facility
Business Dispositions
Disposal Group, Including Discontinued Operation, Consideration		36
Impairment of Long-Lived Assets to be Disposed of		$ 140
CENG [Member]
Business Acquisitions
Equity Method Investment, Ownership Percentage		50.01%		50.01%
Payments of Capital Distribution	$ 400
Due from Affiliates	400	$ 645
CENG Preferred Distribution Return		8.50%
CENG [Member] \| Nine Mile Point
Business Acquisitions
Equity Method Investment, Ownership Percentage		82.00%
CENG [Member] \| Exelon Generation Co L L C [Member]
Business Acquisitions
Equity Method Investment, Ownership Percentage		50.01%		50.01%
Payments of Capital Distribution	400
Due from Affiliates	$ 400	$ 645
CENG Preferred Distribution Return		8.50%
CENG [Member] \| Exelon Generation Co L L C [Member] \| Nine Mile Point
Business Acquisitions
Equity Method Investment, Ownership Percentage		82.00%