Variable Interest Entities - Assets and Liabilities of Consolidated VIES (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021	Dec. 31, 2020
Variable Interest Entity [Line Items]
Cash and cash equivalents	$ 2,476	$ 672	$ 1,908	$ 663
Restricted cash and cash equivalents	430	321	374	438
Accounts receivable, net
Customer	1,976	1,869
Inventory, net
Materials and supplies	473	476
Current assets of discontinued operations	0	7,835
Other current assets	463	387
Total current assets	8,145	13,957
Property, plant and equipment, net	65,465	64,558
Other Assets, Noncurrent	1,045	885
Assets	92,698	133,013
Long-term debt due within one year	2,154	2,153
Accounts payable	2,175	2,379
Accrued expenses	1,029	1,137
Unamortized energy contract liabilities	13	89
Current liabilities of discontinued operations	0	7,940
Other	964	766
Total current liabilities	8,635	16,111
Long-term debt	35,008	30,749
Asset retirement obligations, noncurrent	273	271
Unamortized energy contract liabilities	42	146
Other	2,187	1,573
Liabilities	69,207	98,218
Pepco Holdings LLC [Member]
Variable Interest Entity [Line Items]
Cash and cash equivalents	796	136	558	111
Restricted cash and cash equivalents	106	77	37	39
Accounts receivable, net
Customer	505	512
Inventory, net
Materials and supplies	209	209
Other current assets	69	69
Total current assets	2,368	1,692
Property, plant and equipment, net	16,701	16,498
Other Assets, Noncurrent	253	258
Assets	25,636	24,744
Long-term debt due within one year	400	399
Accounts payable	522	578
Accrued expenses	264	281
Unamortized energy contract liabilities	13	89
Other	215	171
Total current liabilities	1,748	2,246
Long-term debt	7,833	7,148
Asset retirement obligations, noncurrent	70	70
Unamortized energy contract liabilities	42	146
Other	661	570
Liabilities	14,319	14,159
Atlantic City Electric Company [Member]
Variable Interest Entity [Line Items]
Cash and cash equivalents	168	29	353	17
Restricted cash and cash equivalents	0	0	$ 4	$ 3
Accounts receivable, net
Customer	128	141
Inventory, net
Other current assets	5	3
Total current assets	540	333
Property, plant and equipment, net	3,763	3,729
Other Assets, Noncurrent	37	37
Assets	4,929	4,556
Long-term debt due within one year	3	3
Accounts payable	139	165
Accrued expenses	43	44
Other	18	12
Total current liabilities	349	445
Long-term debt	1,754	1,579
Other	165	49
Liabilities	$ 3,174	$ 2,981