Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2011

Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]

Assets and Liabilities Measured at Fair Value on a Recurring Basis [Table Text Block]

Assets and liabilities measured at fair value on a recurring basis at December 31, 2011 and 2010 are as follows:



	Total Cost Basis				Quoted Prices In Active Markets for Identical Assets (Level 1)				Significant Other Observable Inputs (Level 2)					Total Fair Value
Millions of dollars	2011		2010		2011		2010		2011			2010		2011			2010
Money market funds ⁽¹⁾	$	340	$	414	$	340	$	414	$	—		$	—	$	340		$	414
Net derivative contracts	—		—		—		—		(57		)	125		(57		)	125
Available for sale investments	21		27		15		25		—			—		15			25


(1)	Money market funds are primarily comprised of United States government obligations.

- Definition

Tabular disclosure of assets, including [financial] instruments measured at fair value that are classified in stockholders' equity, if any, by class that are measured at fair value on a recurring basis. The disclosures contemplated herein include the fair value measurements at the reporting date by the level within the fair value hierarchy in which the fair value measurements in their entirety fall, segregating fair value measurements using quoted prices in active markets for identical assets (Level 1), significant other observable inputs (Level 2), and significant unobservable inputs (Level 3).

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