Schedule I - Condensed Financial Information of Parent (Exelon Corporate) - Debt and Credit Agreements - Schedule of Outstanding Long-term Debt (Details) (USD $)	12 Months Ended
	Dec. 31, 2014		Jun. 30, 2014	Dec. 31, 2013
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 20,756,000,000			$ 18,760,000,000
Unamortized debt discount and premium, net	(37,000,000)			(19,000,000)
Long-term debt	19,362,000,000			17,623,000,000
Junior Subordinated Debt [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	1,150,000,000		1,150,000,000.00	0
Maximum interest rate on long-term debt	6.50%
Senior Notes [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	7,071,000,000			7,571,000,000
Minimum interest rate on long-term debt	2.00%
Maximum interest rate on long-term debt	7.60%
Exelon Corporate [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	3,808,000,000			2,658,000,000
Unamortized debt discount and premium, net	1,000,000			2,000,000
Fair value adjustment	441,000,000			383,000,000
Long-term debt due within one year	(1,409,000,000)			(10,000,000)
Long-term debt	2,841,000,000			3,033,000,000
Exelon Corporate [Member] | Junior Subordinated Debt [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	1,150,000,000			0
Maximum interest rate on long-term debt	6.50%
Exelon Corporate [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Unsecured Long Term Debt	$ 2,658,000,000	[1]		$ 2,658,000,000	[1]
Minimum interest rate on long-term debt	4.90%	[1]
Maximum interest rate on long-term debt	7.60%	[1]

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