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, 2015	Dec. 31, 2014	Dec. 31, 2013
Related Party Transaction [Line Items]
Total income (loss) in equity method investments			$ (20)	$ 10
Due to Affiliate, Current		$ 8	8
Exelon Corporate [Member]
Related Party Transaction [Line Items]
Operating and maintenance from affiliates		43	38	34
Interest income from affiliates, net		43	53	36
Total income (loss) in equity method investments		2,461	1,779	1,903
Cash contributions received from affiliates		3,209	1,370	1,175
Accounts receivable from affiliates		20	24
Receivables from affiliates		1,478	818
Investments in affiliates		26,119	26,670
Total receivable from affiliates (noncurrent)		933	943
Due to Affiliate, Noncurrent		0	182
Exelon Corporate [Member] | Business Services Company [Member]
Related Party Transaction [Line Items]
Operating and maintenance from affiliates	[1]	43	38	34
Accounts receivable from affiliates	[1]	0	2
Receivables from affiliates	[1]	226	262
Investments in affiliates	[1]	191	193
Exelon Corporate [Member] | Exelon Energy Delivery Company LLC [Member]
Related Party Transaction [Line Items]
Total income (loss) in equity method investments	[2]	1,079	958	834
Investments in affiliates	[2]	14,163	13,590
Exelon Corporate [Member] | Exelon Ventures Company LLC [Member]
Related Party Transaction [Line Items]
Total income (loss) in equity method investments	[3]	0	926	1,076
Exelon Corporate [Member] | UII LLC [Member]
Related Party Transaction [Line Items]
Total income (loss) in equity method investments		20	(6)	(2)
Investments in affiliates		102	130
Exelon Corporate [Member] | Exelon Transmission Company LLC [Member]
Related Party Transaction [Line Items]
Total income (loss) in equity method investments		(8)	(7)	(5)
Investments in affiliates		3	1
Exelon Corporate [Member] | ExelonEnterprise [Member]
Related Party Transaction [Line Items]
Total income (loss) in equity method investments		(1)	(1)	0
Investments in affiliates		22	23
Exelon Corporate [Member] | Exelon Generation Consolidated [Member]
Related Party Transaction [Line Items]
Total income (loss) in equity method investments		1,371	(91)	$ 0
Receivables from affiliates		1,252	556
Investments in affiliates		11,637	12,720
Exelon Corporate [Member] | Exelon Consolidations [Member]
Related Party Transaction [Line Items]
Investments in affiliates		(6)	4
Exelon Corporate [Member] | Exelon Generation Co L L C [Member]
Related Party Transaction [Line Items]
Accounts receivable from affiliates		16	12
Total receivable from affiliates (noncurrent)		933	943
Exelon Corporate [Member] | Commonwealth Edison Co [Member]
Related Party Transaction [Line Items]
Accounts receivable from affiliates		2	3
Due to Affiliate, Current		188
Due to Affiliate, Noncurrent		0	182
Exelon Corporate [Member] | PECO Energy Co [Member]
Related Party Transaction [Line Items]
Accounts receivable from affiliates		1	2
Exelon Corporate [Member] | Baltimore Gas and Electric Company [Member]
Related Party Transaction [Line Items]
Accounts receivable from affiliates		1	5
Exelon Corporate [Member] | VEBA [Member]
Related Party Transaction [Line Items]
Investments in affiliates		$ 7	$ 9

[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 Energy Delivery Company, LLC consists of ComEd, PECO and BGE.

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