Exelon's and ComEd's gross amount of goodwill, accumulated impairment losses and carrying amount of goodwill for the years ended December 31, 2011 and 2010 were as follows:

	2011						2010
			Accumulated						Accumulated
	Gross		Impairment		Carrying		Gross		Impairment		Carrying
	Amount(a)		Losses		Amount		Amount(a)		Losses		Amount

Balance, January 1	$	4,608	$	1,983	$	2,625	$	4,608	$	1,983	$	2,625

Impairment losses		0		0		0		0		0		0

Balance, December 31,	$	4,608	$	1,983	$	2,625	$	4,608	$	1,983	$	2,625

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

Goodwill is not amortized, but is subject to an assessment for impairment at least annually, or more frequently if events or circumstances indicate that goodwill might be impaired. The impairment assessment is performed using a two-step, fair value based test. The first step compares the fair value of the reporting unit to its carrying amount, including goodwill. If the carrying amount of the reporting unit exceeds its fair value, the second step is performed. The second step requires an allocation of fair value to the individual assets and liabilities using purchase price allocation in order to determine the implied fair value of goodwill. If the implied fair value of goodwill is less than the carrying amount, an impairment loss is recorded as a reduction to goodwill and a charge to operating expense.

Exelon assesses goodwill impairment at its ComEd reporting unit. Accordingly, any goodwill impairment charge at ComEd will affect Exelon's consolidated results of operations. Under the effective authoritative guidance for fair value measurement, Exelon and ComEd estimate the fair value of the ComEd reporting unit using a weighted combination of a discounted cash flow analysis and a market multiples analysis. New guidance that does not have an impact on the Step 1 test will become effective for ComEd January 1, 2012. See Note 1 - Significant Accounting Policies for additional information on the new guidance. The discounted cash flow analysis relies on a single scenario reflecting “base case” or “best estimate” projected cash flows for ComEd's business and includes an estimate of ComEd's terminal value based on these expected cash flows using the generally accepted Gordon Dividend Growth formula, which derives a valuation using an assumed perpetual annuity based on the entity's residual cash flows. The discount rate is based on the generally accepted Capital Asset Pricing Model and represents the weighted average cost of capital of comparable companies. The market multiples analysis utilizes multiples of business enterprise value to earnings, before interest, taxes, depreciation and amortization (EBITDA) of comparable companies in estimating fair value. Significant assumptions used in estimating the fair value include discount and growth rates, utility sector market performance and transactions, operating and capital expenditure requirements and the fair value of debt. Management performs a reconciliation of the sum of the estimated fair value of all Exelon reporting units to Exelon's enterprise value based on its trading price to corroborate the results of the discounted cash flow analysis and the market multiple analysis.

2011 Annual Goodwill Impairment Assessment. The 2011 annual goodwill impairment assessment was performed as of November 1, 2011. The first step of the annual impairment analysis, comparing the fair value of ComEd to its carrying value, including goodwill, indicated no impairment of goodwill;, therefore, the second step was not required. Operating and capital expenditure requirements used for the 2011 assessment included the impacts of EIMA discussed in Note 2 - Regulatory Matters. Although the fair value of the reporting unit currently exceeds its carrying value, deterioration in market related factors used in the impairment review, a fully successful IRS challenge to Exelon's and ComEd's like-kind exchange income tax position or adverse regulatory actions such as early termination of EIMA could potentially result in a future impairment loss of ComEd's goodwill, which could be material.

Prior Goodwill Impairment Assessments. The 2010 and 2009 annual goodwill impairment assessments were performed as of November 1, 2010 and November 1, 2009, respectively. In each case, the first step of the annual impairment analysis, comparing the fair value of ComEd to its carrying value, including goodwill, indicated no impairment of goodwill;, therefore, the second step was not required.

Exelon's, Generation's and ComEd's other intangible assets, included in deferred debits and other assets in their Consolidated Balance Sheets, consisted of the following as of December 31, 2011:

								Estimated amortization expense
		Gross		Accumulated Amortization		Net		2012		2013		2014		2015		2016
Generation
	Exelon Wind acquisition (a)	$	224	$	(13)	$	211	$	13	$	14	$	14	$	14	$	14
	Antelope Valley acquisition (b)		190		0		190		0		6		7		7		7
ComEd
	Chicago settlement – 1999 agreement (c)		100		(69)		31		3		3		3		3		3
	Chicago settlement – 2003 agreement (d)		62		(31)		31		4		4		4		4		4

Total intangible assets		$	576	$	(113)	$	463	$	20	$	27	$	28	$	28	$	28

(a) Refer to Note 3 - Acquisition for additional information regarding Exelon Wind.

(b) Refer to Note 3 - Acquisition 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.

The following table summarizes the amortization expense related to intangible assets for each of the years ended December 31, 2011, 2010 and 2009:

For the Year Ended December 31,	Exelon		Generation		ComEd

2011	$	19	$	12	$	7
2010		8		1		7
2009		7		—		7

Accounting guidance for business combinations requires that the acquirer must recognize separately identifiable intangible assets in the application of purchase accounting. The valuation of the acquired intangible assets discussed below were estimated by applying the income approach, which is based upon discounted projected future cash flows associated with the respective PPAs. Those measures are based upon certain unobservable inputs, which are considered Level 3 inputs, pursuant to applicable accounting guidance.

Antelope Valley. Upon completion of the development project, all of the output will be sold under a PPA with Pacific Gas & Electric. The excess of the contract price of the PPA over forecasted MPR-based market prices was recognized as an intangible asset at the acquisition date. Generation determined that the estimated acquisition-date fair value of the intangible asset was approximately $190 million, which was recorded in other deferred debits and other assets within Exelon and Generation's Consolidated Balance Sheets. While Generation expects to perform under the PPA once the construction of this project is complete, there is a risk of impairment if the project does not reach commercial operation.

Key assumptions used in the valuation of the intangible asset include forecasted MRP-based market prices and discount rate. The intangible asset will be amortized as revenue is earned over the 25 term of the underlying PPA. The amortization expense will be reflected as a decrease in operating revenue within Exelon and Generation's Consolidated Statements of Operations and Comprehensive Income.

Exelon Wind. The output of the acquired wind turbines has been sold under PPA contracts. The excess of the contract price of the PPAs over market prices was recognized as intangible assets. Generation determined that the estimated acquisition-date fair value of the intangible assets was approximately $224 million, which was recorded in other deferred debits and other assets within Exelon and Generation's Consolidated Balance Sheets. Included in this amount is $21 million related to the PPAs for the projects that are in the advanced stage of development. While Generation expects to perform under the PPAs once the construction of these projects is complete, there is a risk of impairment if the projects do not reach commercial operation.

Key assumptions used in the valuation of the intangible assets include forecasted power prices and discount rate. The intangible assets will be amortized on a straight-line basis over the period in which the associated contract revenues are recognized. The amortization expense will be reflected as a decrease in operating revenue within Exelon's and Generation's Consolidated Statements of Operations and Comprehensive Income. The weighted-average amortization period for these intangibles is approximately 18 years.

Renewable Energy Credits and Alternative Energy Credits (Exelon, Generation and PECO).

Exelon's, Generation's and PECO's other intangible assets, included in other current assets and other deferred debits and other assets on the Consolidated Balance Sheets, include RECs (Exelon and Generation) and AECs (Exelon and PECO). As of December 31, 2011 and 2010, PECO had current AECs of $14 million and $10 million, respectively, and noncurrent AECs of $16 million and $11 million, respectively. As of December 31, 2011 and 2010, the balances of RECs for Generation, which are considered noncurrent, were $6 million and $8 million, respectively. See Notes 2 - Regulatory Matters and Note 18 - Commitments and Contingencies for additional information on RECs and AECs.