Schedule I - Condensed Financial Information of Parent (Exelon Corporate) - Related Party Transactions - Summary of Related Party Transactions (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Related Party Transaction [Line Items]
Income (Loss) from Equity Method Investments		$ (24)	$ (7)	$ 0
Due to Affiliate, Current		706	0
Exelon Corporate [Member]
Related Party Transaction [Line Items]
Operating and maintenance from affiliates		51	43	38
Interest income from affiliates, net		39	43	53
Income (Loss) from Equity Method Investments		1,521	2,461	1,779
Cash contributions received from affiliates		1,912	3,209	1,370
Accounts receivable from affiliates		48	20
Receivables from affiliates		88	1,478
Investments in affiliates		34,869	26,119
Total receivable from affiliates (noncurrent)		922	933
Due to Affiliate, Current		706
Exelon Corporate [Member] | Business Services Company [Member]
Related Party Transaction [Line Items]
Operating and maintenance from affiliates	[1]	51	43	38
Income (Loss) from Equity Method Investments		1
Accounts receivable from affiliates	[1]	15	0
Receivables from affiliates	[1]	88	226
Investments in affiliates	[1]	194	191
Due to Affiliate, Current		361
Exelon Corporate [Member] | PHI Service Co Affiliate [Member]
Related Party Transaction [Line Items]
Accounts receivable from affiliates		6
Exelon Corporate [Member] | Potomac Capital Investment Affiliate [Member]
Related Party Transaction [Line Items]
Income (Loss) from Equity Method Investments		6
Investments in affiliates	[2]	77
Exelon Corporate [Member] | Exelon Energy Delivery Company LLC [Member]
Related Party Transaction [Line Items]
Income (Loss) from Equity Method Investments	[3]	1,041	1,079	958
Investments in affiliates	[3]	23,003	14,163
Exelon Corporate [Member] | Exelon Ventures Company LLC [Member]
Related Party Transaction [Line Items]
Income (Loss) from Equity Method Investments	[2]	0	0	926
Exelon Corporate [Member] | UII LLC [Member]
Related Party Transaction [Line Items]
Income (Loss) from Equity Method Investments		(9)	20	(6)
Investments in affiliates		92	102
Exelon Corporate [Member] | Exelon Transmission Company LLC [Member]
Related Party Transaction [Line Items]
Income (Loss) from Equity Method Investments		(13)	(8)	(7)
Investments in affiliates		5	3
Exelon Corporate [Member] | ExelonEnterprise [Member]
Related Party Transaction [Line Items]
Income (Loss) from Equity Method Investments		(1)	(1)	(1)
Investments in affiliates		21	22
Exelon Corporate [Member] | Exelon Consolidations [Member]
Related Party Transaction [Line Items]
Investments in affiliates		(6)	(6)
Exelon Corporate [Member] | Exelon Generation Co L L C [Member]
Related Party Transaction [Line Items]
Interest income from affiliates, net		39	43	53
Income (Loss) from Equity Method Investments		496	1,371	$ (91)
Accounts receivable from affiliates		22	16
Receivables from affiliates		0	1,252
Investments in affiliates		11,488	11,637
Total receivable from affiliates (noncurrent)		922	933
Exelon Corporate [Member] | Commonwealth Edison Co [Member]
Related Party Transaction [Line Items]
Accounts receivable from affiliates		3	2
Due to Affiliate, Current		345	188
Exelon Corporate [Member] | PECO Energy Co [Member]
Related Party Transaction [Line Items]
Accounts receivable from affiliates		1	1
Exelon Corporate [Member] | Baltimore Gas and Electric Company [Member]
Related Party Transaction [Line Items]
Accounts receivable from affiliates		1	1
Exelon Corporate [Member] | VEBA [Member]
Related Party Transaction [Line Items]
Investments in affiliates		$ (5)	$ 7

[1] Exelon Corporate receives a variety of corporate support services from BSC, including legal, human resources, financial, information technology and supply management services. All services are provided at cost, including applicable overhead.

[2] Exelon Ventures Company, LLC primarily consisted of Generation

[3] Exelon Energy Delivery Company, LLC consists of ComEd, PECO, BGE, PHI, Pepco, DPL and ACE.