Schedule I - Condensed Financial Information of Parent (Exelon Corporate) - Debt and Credit Agreements - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($)
Line of Credit Facility [Line Items]
Maximum Program Size	$ 9,704	[1]
Line of Credit Facility, Capacity Available for Trade Purchases	7,687
Revolving Credit Facility [Member] | Exelon Corporate [Member]
Line of Credit Facility [Line Items]
Maximum Program Size	600	[1]
Line of Credit Facility, Capacity Available for Trade Purchases	591
Corporate, Non-Segment [Member] | Exelon Corporate [Member]
Line of Credit Facility [Line Items]
Short-term Bank Loans and Notes Payable	$ 500
Debt Instrument, Interest Rate Terms	LIBOR plus 1%

[1] Excludes $135 million of credit facility agreements arranged at minority and community banks at Generation, ComEd, PECO, BGE, Pepco, DPL and ACE with aggregate commitments of $49 million, $33 million, $34 million, $5 million, $5 million, $5 million and $5 million, respectively. These facilities expire on October 11, 2019. These facilities are solely utilized to issue letters of credit. As of December 31, 2018, letters of credit issued under these facilities totaled $5 million and $2 million for Generation and BGE, respectively.