Income Taxes	3 Months Ended
Mar. 31, 2016
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes We estimate our annual effective tax rate based on year-to-date operating results and our forecast for the remainder of the year, by jurisdiction, and apply this rate to the year-to-date operating results. If our actual results, by jurisdiction, differ from the forecasted operating results, our effective tax rate can change, affecting the tax expense for both successive interim results as well as the annual tax results. For the first quarter of 2016, we had a tax benefit of $101 million, on a loss before income taxes of $592 million. Our results for the first quarter of 2016 include charges with no significant tax benefit principally related to a $65 million litigation accrual, $52 million of Zubair project losses and $31 million of currency devaluation related to the Angolan kwanza. We are continuously under tax examination in various jurisdictions. We cannot predict the timing or outcome regarding resolution of these tax examinations or if they will have a material impact on our financial statements. We continue to anticipate a possible reduction in the balance of uncertain tax positions of approximately $16 million in the next twelve months due to expiration of statutes of limitations, settlements and/or conclusions of tax examinations. For the first quarter of 2015, we had no tax provision on a loss before income taxes of $107 million. Our results for the first quarter of 2015 were impacted by discrete loss before tax items, including approximately $41 million of restructuring charges and a $26 million devaluation of the Venezuelan bolivar, with no significant tax benefit.

Income Taxes

3 Months Ended

Mar. 31, 2016

We estimate our annual effective tax rate based on year-to-date operating results and our forecast for the remainder of the year, by jurisdiction, and apply this rate to the year-to-date operating results. If our actual results, by jurisdiction, differ from the forecasted operating results, our effective tax rate can change, affecting the tax expense for both successive interim results as well as the annual tax results. For the first quarter of 2016, we had a tax benefit of $101 million, on a loss before income taxes of $592 million. Our results for the first quarter of 2016 include charges with no significant tax benefit principally related to a $65 million litigation accrual, $52 million of Zubair project losses and $31 million of currency devaluation related to the Angolan kwanza.

We are continuously under tax examination in various jurisdictions. We cannot predict the timing or outcome regarding resolution of these tax examinations or if they will have a material impact on our financial statements. We continue to anticipate a possible reduction in the balance of uncertain tax positions of approximately $16 million in the next twelve months due to expiration of statutes of limitations, settlements and/or conclusions of tax examinations.

For the first quarter of 2015, we had no tax provision on a loss before income taxes of $107 million. Our results for the first quarter of 2015 were impacted by discrete loss before tax items, including approximately $41 million of restructuring charges and a $26 million devaluation of the Venezuelan bolivar, with no significant tax benefit.