Fair Value Measurements

3 Months Ended

Mar. 31, 2012

Fair Value Measurements [Abstract]

Fair Value Measurements

11.    Fair Value Measurements

Assets and Liabilities Accounted for at Fair Value

Our assets and liabilities that are measured at fair value on a recurring basis include the following (in millions):

			Fair Value Measurements at March 31, 2012 Using
	Total		Quoted Prices in Active Markets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets:
Cash equivalents	$	91	$	91	$	—	$	—
Available-for-sale securities		167		142		—		25
Interest rate derivatives		70		—		70		—
Electricity commodity derivatives		6		—		6		—
Total assets	$	334	$	233	$	76	$	25
Liabilities:
Interest rate derivatives	$	69	$	—	$	69	$	—
Foreign currency derivatives		7		—		7		—
Total liabilities	$	76	$	—	$	76	$	—

			Fair Value Measurements at December 31, 2011 Using
	Total		Quoted Prices in Active Markets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets:
Cash equivalents	$	120	$	120	$	—	$	—
Available-for-sale securities		179		154		—		25
Interest rate derivatives		73		—		73		—
Electricity commodity derivatives		5		—		5		—
Total assets	$	377	$	274	$	78	$	25
Liabilities:
Interest rate derivatives	$	74	$	—	$	74	$	—
Foreign currency derivatives		2		—		2		—
Total liabilities	$	76	$	—	$	76	$	—

Fair Value of Available-for-sale Securities — The available-for-sale securities measured using Level 1 inputs are primarily included in long-term “Other assets” in our Condensed Consolidated Balance Sheets. The fair value of available-for-sale securities measured using Level 3 inputs consists of redeemable preferred stock that was acquired in November 2011 and is included in “Investments in unconsolidated entities” in our Condensed Consolidated Balance Sheets. The redeemable preferred stock is recorded at fair value based on other third-party investors’ recent or pending transactions in these securities, which are considered to be the best evidence of fair value currently available. When this evidence is not available, we use other valuation techniques as appropriate and available. These valuation methodologies may include transactions in similar instruments, discounted cash flow techniques, third-party appraisals or industry multiples and public comparables.

Fair Value of Debt

At March 31, 2012 and December 31, 2011, the carrying value of our debt was approximately $9.8 billion. The carrying value of our debt includes adjustments for both the unamortized fair value adjustments related to terminated hedge arrangements and fair value adjustments for debt instruments that are currently hedged.

The estimated fair value of our debt was approximately $11.0 billion at March 31, 2012 and approximately $10.8 billion at December 31, 2011. The estimated fair value of our senior notes is based on quoted market prices. The carrying value of remarketable debt and borrowings under our revolving credit facilities approximates fair value due to the short-term nature of the interest rates. The fair value of our other debt is estimated using discounted cash flow analysis, based on current market rates for similar types of instruments.

Although we have determined the estimated fair value amounts using available market information and commonly accepted valuation methodologies, considerable judgment is required in interpreting market data to develop the estimates of fair value. Accordingly, our estimates are not necessarily indicative of the amounts that we, or holders of the instruments, could realize in a current market exchange. The use of different assumptions and/or estimation methodologies could have a material effect on the estimated fair values. The fair value estimates are based on Level 2 inputs of the fair value hierarchy available as of March 31, 2012 and December 31, 2011. These amounts have not been revalued since those dates, and current estimates of fair value could differ significantly from the amounts presented.