Schedule I - Condensed Financial Information of Parent (Exelon Corporate) - Debt and Credit Agreements - Schedule of Outstanding Long-term Debt (Details) - USD ($)		Dec. 31, 2016	Dec. 31, 2015	Jun. 30, 2015
Debt Instrument [Line Items]
Long-term Debt, Gross		$ 33,311,000,000	$ 25,113,000,000
Unamortized debt discount and premium, net		(68,000,000)	(63,000,000)
Long-term debt		31,575,000,000	23,645,000,000
Unamortized Debt Issuance Expense	[1]	(200,000,000)	(180,000,000)
Junior Subordinated Debt [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross		1,150,000,000	1,150,000,000	$ 1,150,000,000.00
Senior Notes [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross		11,868,000,000	9,803,000,000
contract Payments Junior Subordinate Debt [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross		$ 19,000,000	64,000,000
Maximum [Member] | Junior Subordinated Debt [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		6.50%
Maximum [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		7.60%
Maximum [Member] | contract Payments Junior Subordinate Debt [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		2.50%
Minimum [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		1.55%
Exelon Corporate [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross		$ 7,608,000,000	5,853,000,000
Unamortized debt discount and premium, net		(8,000,000)	(4,000,000)
Fair value adjustment of consolidated subsidiary		220,000,000	275,000,000
Long-term debt due within one year		(570,000,000)	(60,000,000)
Long-term debt		7,193,000,000	6,017,000,000
Unamortized Debt Issuance Expense		(57,000,000)	(47,000,000)
Exelon Corporate [Member] | Junior Subordinated Debt [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross		$ 1,150,000,000	1,150,000,000
Debt Instrument, Interest Rate, Stated Percentage		6.50%
Exelon Corporate [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Unsecured Long Term Debt	[2]	$ 6,439,000,000	4,639,000,000
Exelon Corporate [Member] | contract Payments Junior Subordinate Debt [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross		$ 19,000,000	$ 64,000,000
Debt Instrument, Interest Rate, Stated Percentage		2.50%
Exelon Corporate [Member] | Maximum [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	[2]	7.60%
Exelon Corporate [Member] | Minimum [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	[2]	1.60%

[1] Amounts owed to these financing trusts are recorded as Long-term debt to financing trusts within Exelon’s Consolidated Balance Sheets.

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