Schedule I - Condensed Financial Information of Parent (Exelon Corporate) - Condensed Balance Sheet (Details) - USD ($) $ in Millions		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Feb. 17, 2012
Current assets
Cash and cash equivalents		$ 1,349	$ 898	$ 635	$ 6,502
Accounts receivable, net
Other accounts receivable		1,256	1,132
Regulatory assets, current		1,222	1,267
Other		1,238	1,260
Total current assets		13,360	11,896
Property, plant and equipment, net		76,707	74,202
Deferred debits and other assets
Regulatory assets, noncurrent		8,237	8,021
Other		1,575	1,330
Total assets	[1]	119,666	116,770
Current liabilities
Short-term borrowings		714	929
Long-term debt due within one year		1,349	2,088
Accounts payable		3,800	3,532
Accrued expenses		2,112	1,837
Payables to affiliates, current		5	5
Regulatory Liability, Current		644	523
Other		1,035	1,069
Total current liabilities		11,404	10,798
Long-term debt		34,075	32,176
Deferred credits and other liabilities
Regulatory liabilities, noncurrent		9,559	9,865
Pension obligations		3,988	3,736
Non-pension postretirement benefit obligations		1,928	2,093
Other		2,130	2,097
Total deferred credits and other liabilities		40,727	41,220
Total liabilities	[1]	86,596	84,583
Commitments and Contingencies						$ 1,000
Shareholders’ equity
Common stock		19,116	18,964
Treasury stock, at cost		(123)	(123)
Retained earnings		14,766	14,081
Accumulated other comprehensive income (loss), net		(2,995)	(3,026)
Total shareholders’ equity		30,764	29,896
Total liabilities and equity		119,666	116,770
Exelon Corporate [Member]
Current assets
Cash and cash equivalents		189	74	$ 18	$ 5,690
Accounts receivable, net
Other accounts receivable		48	431
Accounts receivable from affiliates, current		44	33
Note receivable from affiliates, current		216	217
Regulatory assets, current		182	284
Other		4	4
Total current assets		683	1,043
Property, plant and equipment, net		48	50
Deferred debits and other assets
Regulatory assets, noncurrent		3,742	3,697
Investments in affiliates		40,448	39,311
Deferred income taxes		1,455	1,431
Notes receivable from affiliates, noncurrent		898	910
Other		235	234
Total deferred debits and other assets		46,778	45,583
Total assets		47,509	46,676
Current liabilities
Short-term borrowings		500	500
Accounts payable		1	2
Accrued expenses		184	99
Payables to affiliates, current		360	360
Regulatory Liability, Current		15	16
Pension obligations		63	65
Other		14	46
Total current liabilities		1,137	1,088
Long-term debt		7,147	7,161
Deferred credits and other liabilities
Regulatory liabilities, noncurrent		32	15
Pension obligations		7,795	7,792
Non-pension postretirement benefit obligations		199	322
Deferred income taxes		233	220
Other		202	180
Total deferred credits and other liabilities		8,461	8,529
Total liabilities		16,745	16,778
Commitments and Contingencies
Shareholders’ equity
Common stock		19,116	18,966
Treasury stock, at cost		(123)	(123)
Retained earnings		14,766	14,081
Accumulated other comprehensive income (loss), net		(2,995)	(3,026)
Total shareholders’ equity		30,764	29,898
Total liabilities and equity		$ 47,509	$ 46,676

[1] Exelon’s consolidated assets include $9,667 million and $9,597 million at December 31, 2018 and 2017, respectively, of certain VIEs that can only be used to settle the liabilities of the VIE. Exelon’s consolidated liabilities include $3,548 million and $3,618 million at December 31, 2018 and 2017, respectively, of certain VIEs for which the VIE creditors do not have recourse to Exelon. See Note 2–Variable Interest Entities for additional information.