Financial Instruments

12 Months Ended

Dec. 31, 2012

Financial Instruments, Owned, at Fair Value [Abstract]

Financial Instruments

Note 5. Financial Instruments

Cash and cash equivalents, accounts and notes receivable, and accounts payable are carried at cost, which approximates fair value. Our short-term investments (consisting primarily of time deposits, commercial paper, and Treasury securities), totaling $1.8 billion and $150 million as of December 31, 2012 and 2011, respectively, are recorded at amortized cost, and the respective carrying amounts approximate fair value. The fair value of our marketable equity securities, totaling $45 million and $43 million as of December 31, 2012 and 2011, respectively, is measured on a recurring basis using quoted prices in active markets.

The estimated fair value of current and long-term debt, excluding the convertible bond, is determined based on quoted prices in active markets or by using other observable inputs that are derived principally from or corroborated by observable market data. To estimate the fair value of our convertible bond, we used a convertible bond pricing model based on the relevant interest rates, conversion feature and other significant inputs not observable in the market. The significant unobservable inputs used in the fair value measurement of the Company's convertible bond are the credit condition of the Company, probability and timing of conversion, and discount for lack of marketability. Significant increases or decreases in any of those inputs in isolation would result in a significantly lower or higher fair value measurement of the bond. During 2012, we had $2.0 billion of long-term senior notes that were transferred out of estimated fair value using observable inputs and into estimated fair value using quoted prices in active markets as a result of publicly registering our private placement senior note offerings.

The following table presents carrying amounts and estimated fair values of our current and long-term debt:

	Estimated Fair Value Using Input Type
	Carrying Amount		Quoted prices in active markets		Observable		Unobservable		Total estimated fair value
	(in millions)
December 31, 2012	$	23,570	$	17,506	$	6,118	$	3,104	$	26,728
December 31, 2011	$	19,505	$	12,567	$	5,023	$	—	$	17,590