Discontinued Operations and Disposal Groups (Details) - Balance Sheet - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021	Dec. 31, 2020
Discontinued Operations - Income Statement
Restricted cash	$ 430	$ 321	$ 374	$ 438
Customer accounts receivable	2,365	2,189
Accounts Receivable, Allowance for Credit Loss, Current	(389)	(320)
Other accounts receivable	1,148	1,068
Allowance for Credit Loss, Receivable, Other, Current	(81)	(72)
Other Receivables, Net, Current	1,067	996
Fossil fuel and emission allowances	39	105
Materials and supplies inventory, net	473	476
Current assets of discontinued operations	0	7,835
Accumulated depreciation and amortization	14,878	14,430
Investments	244	250
Other Assets, Noncurrent	1,045	885
Property, plant, and equipment, deferred debits, and other assets of discontinued operations	0	38,509
Assets	92,698	133,013
Short-term Debt	1,900	1,248
Long-term Debt and Lease Obligation, Current	2,154	2,153
Mark-to-market derivative liabilities (current liabilities)	0	18
Current liabilities of discontinued operations	0	7,940
Long-term Debt, Excluding Current Maturities	35,008	30,749
Deferred income taxes and unamortized investment tax credits	11,089	10,611
Asset retirement obligations, noncurrent	273	271
Derivative Liability, Noncurrent	144	201
Other	2,187	1,573
Long-term debt, deferred credits, and other liabilities of discontinued operations	0	25,676
Liabilities	$ 69,207	98,218
Exelon Generation Co L L C [Member]
Discontinued Operations - Income Statement
Disposal Group, Including Discontinued Operation, Cash and Cash Equivalents		510
Restricted cash		72
Customer accounts receivable		1,724
Accounts Receivable, Allowance for Credit Loss, Current		(55)
Disposal Group, Including Discontinued Operation, Accounts, Notes and Loans Receivable, Net		1,669
Other accounts receivable		596
Allowance for Credit Loss, Receivable, Other, Current		(4)
Other Receivables, Net, Current		592
Mark-to-market derivative assets, current		2,169
Fossil fuel and emission allowances		284
Materials and supplies inventory, net		1,004
Renewable energy credits, current		529
Disposal Group, Including Discontinued Operations, Assets, Current - Assets held for sale		13
Disposal Group, Including Discontinued Operation, Other Assets, Current		993
Current assets of discontinued operations		7,835
Accumulated depreciation and amortization		15,888
Disposal Group, Including Discontinued Operation, Property, Plant and Equipment, Noncurrent		19,661
Nuclear decommissioning trust funds		15,938
Investments		193
Derivative Asset, Noncurrent		949
Other Assets, Noncurrent		1,768
Property, plant, and equipment, deferred debits, and other assets of discontinued operations		38,509
Assets		46,344
Short-term Debt		2,082
Long-term Debt and Lease Obligation, Current		1,220
Disposal Group, Including Discontinued Operation, Accounts Payable, Current		1,757
Disposal Group, Including Discontinued Operation, Accrued Liabilities, Current		818
Mark-to-market derivative liabilities (current liabilities)		981
Energy Marketing Accounts Payable		779
Disposal Group, Including Discontinued Operations, Assets, Current - Liabilities held for sale		3
Disposal Group, Including Discontinued Operation, Other Liabilities, Current		300
Current liabilities of discontinued operations		7,940
Long-term Debt, Excluding Current Maturities		4,575
Deferred income taxes and unamortized investment tax credits		3,583
Asset retirement obligations, noncurrent		12,819
Disposal Group, Including Discontinued Operation, Pension Plan Benefit Obligation, Noncurrent		939
Disposal Group, Including Discontinued Operation, Postretirement Plan Benefit Obligation, Noncurrent		876
Spent Nuclear Fuel Obligation, Noncurrent		1,210
Derivative Liability, Noncurrent		513
Other		1,161
Long-term debt, deferred credits, and other liabilities of discontinued operations		25,676
Liabilities		$ 33,616