Income Taxes (Tables)

9 Months Ended

Sep. 30, 2012

Income Tax Expense (Benefit), Continuing Operations, Income Tax Reconciliation [Abstract]

Schedule of Effective Income Tax Rate Reconciliation

The following table summarizes the difference between income tax expense at the United States statutory rate of 35% and the income tax expense (benefit) at effective worldwide tax rates for the periods presented:

	Three Months Ended September 30,						Nine Months Ended September 30,
Millions of dollars	2012			2011			2012			2011
Earnings (loss) before income taxes	$	127		$	58		$	384		$	(158	)
Income tax expense computed at United States statutory tax rate	$	44		$	20		$	134		$	(55	)
U.S. government tax incentive - Energy Tax Credits	—			(122		)	—			(255		)
Valuation allowance release	—			—			(55		)	—
Foreign government tax incentive - BEFIEX	(4		)	(28		)	(11		)	(66		)
Other	7			7			19			23
Income tax expense (benefit) computed at effective worldwide tax rates	$	47		$	(123	)	$	87		$	(353	)