Schedule I - Condensed Financial Information of Parent (Exelon Corporate) - Debt and Credit Agreements - Narrative (Details) - USD ($)		12 Months Ended
		Dec. 31, 2017	Mar. 23, 2017	Nov. 30, 2016
Line of Credit Facility [Line Items]
Document Period End Date		Dec. 31, 2017
Maximum Program Size				$ 98
Line of Credit Facility, Capacity Available for Trade Purchases	[1]	$ 7,657,000,000
Exelon Corporate [Member]
Line of Credit Facility [Line Items]
Short-term Bank Loans and Notes Payable			$ 500,000,000
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Maximum Program Size	[2]	9,480,000,000
Revolving Credit Facility [Member] | Exelon Corporate [Member]
Line of Credit Facility [Line Items]
Maximum Program Size	[2]	600,000,000
Line of Credit Facility, Capacity Available for Trade Purchases	[1]	$ 555,000,000

[1] Pepco, DPL and ACE's revolving credit facility is subject to available borrowing capacity. The borrowing capacity may be increased or decreased during the term of the facility, except that (i) the sum of the borrowing capacity must equal the total amount of the facility, and (ii) the aggregate amount of credit used at any given time by each of Pepco, DPL or ACE may not exceed $900 million or the maximum amount of short-term debt the company is permitted to have outstanding by its regulatory authorities. The total number of the borrowing reallocations may not exceed eight per year during the term of the facility.

[2] Excludes additional credit facility agreements for Generation, ComEd, PECO, BGE, Pepco, DPL and ACE with aggregate commitments of $49 million, $34 million, $34 million, $5 million, $2 million, $2 million and $2 million, respectively, arranged with minority and community banks located primarily within utilities' service territories. These facilities expire on October 12, 2018. These facilities are solely utilized to issue letters of credit. As of December 31, 2017, letters of credit issued under these facilities totaled $5 million and $2 million for Generation and BGE, respectively.