Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2012

Schedule Of Goodwill And Intangible Assets [Line Items]

Schedule Of Goodwill Text Block

	2012 and 2011
			Accumulated
	Gross		Impairment		Carrying
	Amount(a)		Losses		Amount
Balance, January 1,	$	4,608	$	1,983	$	2,625
Impairment losses		0		0		0
Balance, December 31,	$	4,608	$	1,983	$	2,625

__________

(a)Reflects goodwill recorded in 2000 from the PECO/Unicom (predecessor parent company of ComEd)merger net of amortization, resolution of tax matters and other non-impairment-related changes as allowed under previous authoritative guidance.

Schedule of Finite-Lived Intangible Assets [Table Text Block]

								Estimated amortization expense
		Gross		Accumulated Amortization		Net		2013		2014		2015		2016		2017
Generation
	Exelon Wind acquisition (a)	$	224	$	(26)	$	198	$	14	$	14	$	14	$	14	$	14
	Antelope Valley acquisition (b)		190		0		190		7		8		8		8		8
ComEd
	Chicago settlement – 1999 agreement (c)		100		(72)		28		3		3		3		3		4
	Chicago settlement – 2003 agreement (d)		62		(34)		28		4		4		4		4		3
Total intangible assets		$	576	$	(132)	$	444	$	28	$	29	$	29	$	29	$	29

__________

(a)       Refer to Note 4 –Merger and Acquisitions for additional information regarding Exelon Wind.

(b)       Refer to Note 4 –Merger and Acquisitions for additional information regarding Antelope Valley.

(c)       In March 1999, ComEd entered into a settlement agreement with the City of Chicago associated with ComEd's franchise agreement. Under the terms of the settlement, ComEd agreed to make payments to the City of Chicago each year from 1999 to 2002. The intangible asset recognized as a result of these payments is being amortized ratably over the remaining term of the franchise agreement, which ends in 2020.

(d)       In February 2003, ComEd entered into separate agreements with the City of Chicago and with Midwest Generation, LLC (Midwest Generation). Under the terms of the settlement agreement with the City of Chicago, ComEd agreed to pay the City of Chicago a total of $60 million over a ten-year period, beginning in 2003. The intangible asset recognized as a result of the settlement agreement is being amortized ratably over the remaining term of the City of Chicago franchise agreement, which ends in 2020. As required by the settlement, ComEd also made a payment of $2 million to a third party on the City of Chicago's behalf. Under the terms of the agreement with Midwest Generation, ComEd received payments of $32 million from Midwest Generation to relieve Midwest Generation's obligation under the 1999 fossil sale agreement with ComEd to build the generation facility in the City of Chicago. The payments received by ComEd, which have been recorded in other long-term liabilities, are being recognized ratably (approximately $2 million annually) as an offset to amortization expense over the remaining term of the franchise agreement.

Schedule Of Finite-Lived Intangible Assets Amortization Expense [Text Block]

For the Year Ended December 31,	Exelon		Generation		ComEd
2012	$	20	$	13	$	7
2011		19		12		7
2010		8		1		7

Commonwealth Edison Co [Member]

Schedule Of Goodwill And Intangible Assets [Line Items]

Schedule Of Goodwill Text Block

	2012 and 2011
			Accumulated
	Gross		Impairment		Carrying
	Amount(a)		Losses		Amount
Balance, January 1,	$	4,608	$	1,983	$	2,625
Impairment losses		0		0		0
Balance, December 31,	$	4,608	$	1,983	$	2,625