Our Assets and Liabilities with Recurring Fair Value Measurements

6 Months Ended

Jun. 30, 2011

Assets and Liabilities with Recurring Fair Value Measurements [Abstract]

Assets and Liabilities with Recurring Fair Value Measurements

6.Assets and Liabilities with Recurring Fair Value Measurements

Cash Equivalents—Highly liquid investments which meet the definition of cash equivalents, primarily investments in money market accounts, are included in both our cash and cash equivalents and in restricted cash on our Consolidated Condensed Balance Sheets. Certain of our money market accounts invest in U.S. Treasury securities or other obligations issued or guaranteed by the U.S. Government, its agencies or instrumentalities. Our cash equivalents are classified within level 1 of the fair value hierarchy.

Margin Deposits and Margin Deposits Held by Us Posted by Our Counterparties—Margin deposits and margin deposits held by us posted by our counterparties represent cash collateral paid between our counterparties and us to support our commodity contracts. Our margin deposits and margin deposits held by us posted by our counterparties are generally cash and cash equivalents and are classified within level 1 of the fair value hierarchy.

Derivatives—The primary factors affecting the fair value of our derivative instruments at any point in time are the volume of open derivative positions (MMBtu, MWh and $ notional amounts); market price levels, primarily for power and natural gas; our credit standing and that of our counterparties; and prevailing interest rates for our interest rate swaps. Prices for power and natural gas are volatile, which can result in material changes in the fair value measurements reported in our financial statements in the future.

We utilize market data, such as pricing services and broker quotes, and assumptions that we believe market participants would use in pricing our assets or liabilities including assumptions about risks and the risks inherent to the inputs in the valuation technique. These inputs can be either readily observable, market corroborated or generally unobservable. The market data obtained from broker pricing services is evaluated to determine the nature of the quotes obtained and, where accepted as a reliable quote, used to validate our assessment of fair value; however, other qualitative assessments can also be used to determine the level of activity in any given market. We primarily apply the market approach and income approach for recurring fair value measurements and utilize what we believe to be the best available information. We utilize valuation techniques that seek to maximize the use of observable inputs and minimize the use of unobservable inputs. We classify fair value balances based on the observability of those inputs.

The fair value of our derivatives includes consideration of our credit standing, the credit standing of our counterparties and the impact of credit enhancements, if any. We have also recorded credit reserves in the determination of fair value based on our expectation of how market participants would determine fair value. Such valuation adjustments are generally based on market evidence, if available, or our best estimate.

Our level1 fair value derivative instruments primarily consist of natural gas swaps, futures and options traded on the NYMEX.

Our level2 fair value derivative instruments primarily consist of interest rate swaps and OTC power and natural gas forwards for which market-based pricing inputs are observable. Generally, we obtain our level2 pricing inputs from markets such as the Intercontinental Exchange and Bloomberg. To the extent we obtain prices from brokers in the marketplace, we have procedures in place to ensure that prices represent executable prices for market participants. In certain instances, our level2 derivative instruments may utilize models to measure fair value. These models are primarily industry-standard models that incorporate various assumptions, including quoted interest rates, correlation, volatility, as well as other relevant economic measures. Substantially all of these assumptions are observable in the marketplace throughout the full term of the instrument, can be derived from observable data or are supported by observable levels at which transactions are executed in the marketplace.

Our level3 fair value derivative instruments primarily consist of our OTC power and natural gas forwards and options where pricing inputs are unobservable, as well as other complex and structured transactions. Complex or structured transactions are tailored to our or our customers‘ needs and can introduce the need for internally-developed model inputs which might not be observable in or corroborated by the market. When such inputs have a significant impact on the measurement of fair value, the instrument is categorized in level3. Our valuation models may incorporate historical correlation information and extrapolate available broker and other information to future periods. In cases where there is no corroborating market information available to support significant model inputs, we initially use the transaction price as the best estimate of fair value. OTC options are valued using industry-standard models, including the Black-Scholes pricing model. At each balance sheet date, we perform an analysis of all instruments subject to fair value measurement and include in level3 all of those whose fair value is based on significant unobservable inputs.

The following tables present our financial assets and liabilities that were accounted for at fair value on a recurring basis at June30, 2011, and December31, 2010, by level within the fair value hierarchy. Financial assets and liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. Our assessment of the significance of a particular input to the fair value measurement requires judgment, and may affect our estimate of the fair value of our assets and liabilities and their placement within the fair value hierarchy levels.

	Assets and Liabilities with Recurring Fair Value Measures at June 30, 2011
	Level 1		Level 2		Level 3		Total
	(in millions)
Assets:
Cash equivalents(1)	$	1,334	$	—	$	—	$	1,334
Margin deposits		133		—		—		133
Commodity instruments:
Commodity futures contracts		460		—		—		460
Commodity forward contracts(2)		—		173		45		218
Interest rate swaps		—		1		—		1
Total assets	$	1,927	$	174	$	45	$	2,146
Liabilities:
Commodity instruments:
Commodity futures contracts	$	414	$	—	$	—	$	414
Commodity forward contracts(2)		—		112		24		136
Interest rate swaps		—		314		—		314
Total liabilities	$	414	$	426	$	24	$	864

	Assets and Liabilities with Recurring Fair Value Measures at December 31, 2010
	Level 1		Level 2		Level 3		Total
	(in millions)
Assets:
Cash equivalents(1)	$	1,297	$	—	$	—	$	1,297
Margin deposits		162		—		—		162
Commodity instruments:
Commodity futures contracts		550		—		—		550
Commodity forward contracts(2)		—		287		54		341
Interest rate swaps		—		4		—		4
Total assets	$	2,009	$	291	$	54	$	2,354
Liabilities:
Margin deposits held by us posted by our counterparties	$	6	$	—	$	—	$	6
Commodity instruments:
Commodity futures contracts		574		—		—		574
Commodity forward contracts(2)		—		119		24		143
Interest rate swaps		—		371		—		371
Total liabilities	$	580	$	490	$	24	$	1,094

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(1) At June 30, 2011, and December 31, 2010, we had cash equivalents of $1,144 million and $1,094 million included in cash and cash equivalents and $190 million and $203 million included in restricted cash, respectively.

(2) Includes OTC swaps and options.

The following table sets forth a reconciliation of changes in the fair value of our net derivative assets (liabilities) classified as level3 in the fair value hierarchy for the periods indicated (in millions):

	Three Months Ended June 30,						Six Months Ended June 30,
	2011			2010			2011			2010
Balance, beginning of period	$	12		$	57		$	30		$	38
Realized and unrealized gains (losses):
Included in netloss:
Included in operating revenues(1)		10			10			6			29
Included in fuel and purchased energy expense(2)		1			(3	)		—			(3	)
Included in OCI		4			(5	)		5			—
Purchases, issuances, sales and settlements:
Purchases		1			—			1			—
Settlements		(7	)		(16	)		(21	)		(22	)
Transfers into and/or out of level 3:(3)
Transfers out of level 3(4)		—			—			—			1
Balance, end of period	$	21		$	43		$	21		$	43
Change in unrealized gains relating to instruments held at end of period	$	11		$	7		$	7		$	26

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(1) For power contracts and Heat Rate swaps and options, included on our Consolidated Condensed Statements of Operations.

(2) For natural gas contracts, swaps and options, included on our Consolidated Condensed Statements of Operations.

(3) We transfer amounts among levels of the fair value hierarchy as of the end of each period. There were no significant transfers into/out of level 1 or out of level 2 or into level 3 during the three and six months ended June 30, 2011 and 2010.

(4) There were no significant transfers into level 2 or out of level 3 for the three months ended June 30, 2011 and 2010, and the six months ended June 30, 2011. We had $(1) million in losses transferred out of level 3 into level 2 for the six months ended June 30, 2010. Transfers out of level 3 into level 2 were due to changes in market liquidity in various power markets.