Variable Interest Entities - Assets and Liabilities of Consolidated VIES (Details) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021	Jun. 30, 2021	Dec. 31, 2020
Variable Interest Entity [Line Items]
Cash and cash equivalents	$ 816	$ 672	$ 1,578	$ 432
Restricted cash and cash equivalents	961	321	379	349
Accounts receivable, net
Customer	1,865	1,869
Inventory, net
Materials and supplies	491	476
Current assets of discontinued operations	0	7,835
Other current assets	515	387
Total current assets	7,342	13,957
Property, plant and equipment, net	66,456	64,558
Other Assets, Noncurrent	1,017	885
Assets	92,295	133,013
Long-term debt due within one year	505	2,153
Accounts payable	2,451	2,379
Accrued expenses	1,057	1,137
Unamortized energy contract liabilities	11	89
Current liabilities of discontinued operations	0	7,940
Other	1,588	766
Total current liabilities	8,031	16,111
Long-term debt	35,789	30,749
Asset retirement obligations, noncurrent	275	271
Unamortized energy contract liabilities	38	146
Other	2,054	1,573
Liabilities	68,639	98,218
Pepco Holdings LLC [Member]
Variable Interest Entity [Line Items]
Cash and cash equivalents	278	136	61	111
Restricted cash and cash equivalents	341	77	42	39
Accounts receivable, net
Customer	567	512
Inventory, net
Materials and supplies	217	209
Other current assets	90	69
Total current assets	2,188	1,692
Property, plant and equipment, net	16,915	16,498
Other Assets, Noncurrent	245	258
Assets	25,592	24,744
Long-term debt due within one year	200	399
Accounts payable	574	578
Accrued expenses	246	281
Unamortized energy contract liabilities	11	89
Other	580	171
Total current liabilities	1,967	2,246
Long-term debt	7,827	7,148
Asset retirement obligations, noncurrent	70	70
Unamortized energy contract liabilities	38	146
Other	615	570
Liabilities	14,468	14,159
Atlantic City Electric Company [Member]
Variable Interest Entity [Line Items]
Cash and cash equivalents	233	29	11	17
Restricted cash and cash equivalents	0	0	$ 3	$ 3
Accounts receivable, net
Customer	149	141
Inventory, net
Other current assets	7	3
Total current assets	659	333
Property, plant and equipment, net	3,798	3,729
Other Assets, Noncurrent	34	37
Assets	5,052	4,556
Long-term debt due within one year	3	3
Accounts payable	157	165
Accrued expenses	43	44
Other	149	12
Total current liabilities	506	445
Long-term debt	1,754	1,579
Other	143	49
Liabilities	$ 3,305	$ 2,981