Mergers, Acquisitions, and Dispositions - Changes in Ownership Equity (Details) - USD ($) $ in Millions		12 Months Ended
	Aug. 06, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Schedule of Changes in Ownership Interest [Line Items]
Net income attributable to common shareholders		$ 1,706	$ 1,963	$ 2,936
Acquisition of CENG noncontrolling interest		885	$ 0	$ 0
Deferred Tax Liability Adjustment - Noncontrolling Interest		(290)
Change from net income (loss) attributable to ownership interest and transfers from Noncontrolling Interest		2,496
CENG [Member]
Schedule of Changes in Ownership Interest [Line Items]
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners	49.99%
CENG [Member]
Schedule of Changes in Ownership Interest [Line Items]
Acquisition of CENG noncontrolling interest	$ 885	1,080
Deferred Tax Liability Adjustment - Noncontrolling Interest		$ (290)
Exelon Generation Co L L C [Member]
Schedule of Changes in Ownership Interest [Line Items]
Acquisition of CENG noncontrolling interest	$ 885
Exelon Generation Co L L C [Member] | CENG [Member]
Schedule of Changes in Ownership Interest [Line Items]
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners	49.99%