Changes in Accumulated Other Comprehensive Income - Schedule of Changes in AOCI (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Movement in Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	$ 34,795	$ 34,868	$ 34,573
Other Comprehensive Income (Loss), Net of Tax	89	650	(206)
Ending Balance	24,744	34,795	34,868
Cash Flow Hedges
Movement in Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	(6)	(5)	(2)
OCI before reclassifications	2	(1)	(3)
Amounts reclassified from AOCI	0	0	0
Other Comprehensive Income (Loss), Net of Tax	2	(1)	(3)
Ending Balance	2	(6)	(5)
Cash Flow Hedges | Exelon Generation Co L L C [Member]
Movement in Accumulated Other Comprehensive Income [Roll Forward]
Other Comprehensive Income (Loss), Net of Tax	6
Pension and Non-Pension Postretirement Benefit Plan Items (a)
Movement in Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	(2,721)	(3,372)	(3,165)
OCI before reclassifications	46	432	(357)
Amounts reclassified from AOCI	41	219	150
Other Comprehensive Income (Loss), Net of Tax	87	651	(207)
Ending Balance	(640)	(2,721)	(3,372)
Pension and Non-Pension Postretirement Benefit Plan Items (a) | Exelon Generation Co L L C [Member]
Movement in Accumulated Other Comprehensive Income [Roll Forward]
Other Comprehensive Income (Loss), Net of Tax	1,994
Foreign Currency Items
Movement in Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	(23)	(23)	(27)
OCI before reclassifications	0	0	4
Amounts reclassified from AOCI	0	0	0
Other Comprehensive Income (Loss), Net of Tax	0	0	4
Ending Balance	0	(23)	(23)
Foreign Currency Items | Exelon Generation Co L L C [Member]
Movement in Accumulated Other Comprehensive Income [Roll Forward]
Other Comprehensive Income (Loss), Net of Tax	23
Total
Movement in Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	(2,750)	(3,400)	(3,194)
OCI before reclassifications	48	431	(356)
Amounts reclassified from AOCI	41	219	150
Other Comprehensive Income (Loss), Net of Tax	89	650	(206)
Ending Balance	(638)	$ (2,750)	$ (3,400)
Total | Exelon Generation Co L L C [Member]
Movement in Accumulated Other Comprehensive Income [Roll Forward]
Other Comprehensive Income (Loss), Net of Tax	$ 2,023