Discontinued Operations Cash Flow - (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Business Dispositions [Line Items]
Depreciation, Amortization and Accretion, Net	$ 3,506	$ 3,533	$ 7,573
Gain (Loss) on Sale of Assets and Asset Impairment Charges	10	8	201
Deferred Income Taxes and Tax Credits	319	255	18
Net fair value changes related to derivatives	(22)	53	568
Gain (Loss) on Investments	0	(205)	586
Net unrealized losses (gains) on equity investments	0	(16)	(160)
Other non-cash operating activities	335	(370)	200
Payments to Acquire Property, Plant, and Equipment	(7,408)	(7,147)	(7,981)
Collection of DPP	0	169	3,902
(Decrease) increase in capital expenditures not paid	(215)	36	16
Increase in DPP	0	348	3,652
(Decrease) increase in PP&E related to ARO update	(13)	332	642
Exelon Generation Co L L C
Business Dispositions [Line Items]
Depreciation, Amortization and Accretion, Net	0	207	4,540
Asset impairment charges		0	545
Gain (Loss) on Sale of Assets and Asset Impairment Charges	0	9	(201)
Deferred Income Taxes and Tax Credits	0	(143)	(224)
Net fair value changes related to derivatives	0	(59)	(568)
Gain (Loss) on Investments	0	205	(586)
Net unrealized losses (gains) on equity investments	0	16	160
Other non-cash operating activities	0	36	(946)
Payments to Acquire Property, Plant, and Equipment	0	(227)	(1,341)
Collection of DPP	0	169	3,902
(Decrease) increase in capital expenditures not paid	0	(128)	96
Increase in DPP	0	348	3,652
(Decrease) increase in PP&E related to ARO update	$ 0	$ 335	$ 618