Fair Value of Financial Instruments	9 Months Ended
Fair Value of Financial Instruments	Sep. 30, 2012
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	Fair Value of Financial Instruments The carrying amount of cash and equivalents, receivables, and accounts payable, as reflected in the condensed consolidated balance sheets, approximates fair value due to the short maturities of these instruments. We have no financial instruments measured at fair value using unobservable inputs. The fair value of our long-term debt was $6.5 billion as of September 30, 2012 and $6.2 billion as of December 31, 2011, which differs from the carrying amount of $4.8 billion as of both September 30, 2012 and December 31, 2011, on our condensed consolidated balance sheets. As of September 30, 2012 and December 31, 2011, $3.8 billion and $3.6 billion of the fair value of our long-term debt were calculated using quoted prices in active markets for identical liabilities (Level 1). As of September 30, 2012 and December 31, 2011, $2.7 billion and $2.6 billion of the fair value of our long-term debt were calculated using significant observable inputs for similar liabilities (Level 2). We hold a series of interest rate swaps relating to two of our debt instruments with a total notional amount of $1.0 billion at a weighted-average, LIBOR-based, floating rate of 3.4% as of September 30, 2012. We utilize interest rate swaps to effectively convert a portion of our fixed rate debt to floating rates. These interest rate swaps, which expire when the underlying debt matures, are designated as fair value hedges of the underlying debt and are determined to be highly effective. The fair value of our interest rate swaps is included in “Other assets” in our condensed consolidated balance sheets as of September 30, 2012 and December 31, 2011. The fair value of our interest rate swaps was determined using an income approach model with inputs, such as the notional amount, LIBOR rate spread, settlement terms, and counterparty credit risk, that are observable in the market or can be derived from or corroborated by observable data (Level 2). These derivative instruments are marked to market with gains and losses recognized currently in interest expense to offset the respective gains and losses recognized on changes in the fair value of the hedged debt. At September 30, 2012, we had fixed rate debt aggregating $3.8 billion and variable rate debt aggregating $1.0 billion, after taking into account the effects of the interest rate swaps. The fair value of our interest rate swaps was not material as of September 30, 2012.

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

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