Income Taxes	6 Months Ended
Jun. 30, 2017
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes We have historically calculated the provision for income taxes during interim reporting periods by applying an estimate of the annual effective tax rate for the full fiscal year to ordinary income or loss (pre-tax income or loss excluding unusual or infrequently occurring discrete items and pre-tax losses for which no benefit has been recognized) for the reporting period. For the three month and six month periods ended June 30, 2017, we determined that since small changes in estimated ordinary annual income would result in significant changes in the estimated annual effective tax rate, the use of a discrete effective tax rate is appropriate for the current quarter. The discrete method treats the year-to-date period as if it was the annual period and determines the income tax expense or benefit on that basis. We will use this method each quarter until the annual effective tax rate method is deemed appropriate. For the second quarter and the first six months of 2017, we had a tax expense of $17 million and $50 million, respectively, on a loss before income taxes of $148 million and $558 million, respectively. Results for the second quarter and the first six months of 2017 include losses with no significant tax benefit. The tax expense for the second quarter and the first six months of 2017 also includes withholding taxes and deemed profit taxes that do not directly correlate to ordinary income or loss. 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 $10 million in the next twelve months due to expiration of statutes of limitations, settlements and/or conclusions of tax examinations. For both the second quarter and the first six months of 2016, we had a tax benefit of $102 million and $203 million, respectively, on a loss before income taxes of $664 million and $1.26 billion, respectively. Our results for the second quarter of 2016 include charges with no significant tax benefit principally related to $75 million of settlement charges, $78 million of bond tender premium, and $84 million of a note adjustment related to our largest customer in Venezuela, partially offset by $52 million of Zubair project gain with no significant tax expense. Our results for the first six months of 2016 include charges with no significant tax benefit principally related to $140 million of settlement charges, $31 million of currency devaluation related to the Angolan kwanza, $78 million of bond tender premium, and $84 million related to a note adjustment for our largest customer in Venezuela.

Income Taxes

We have historically calculated the provision for income taxes during interim reporting periods by applying an estimate of the annual effective tax rate for the full fiscal year to ordinary income or loss (pre-tax income or loss excluding unusual or infrequently occurring discrete items and pre-tax losses for which no benefit has been recognized) for the reporting period. For the three month and six month periods ended June 30, 2017, we determined that since small changes in estimated ordinary annual income would result in significant changes in the estimated annual effective tax rate, the use of a discrete effective tax rate is appropriate for the current quarter. The discrete method treats the year-to-date period as if it was the annual period and determines the income tax expense or benefit on that basis. We will use this method each quarter until the annual effective tax rate method is deemed appropriate. For the second quarter and the first six months of 2017, we had a tax expense of $17 million and $50 million, respectively, on a loss before income taxes of $148 million and $558 million, respectively. Results for the second quarter and the first six months of 2017 include losses with no significant tax benefit. The tax expense for the second quarter and the first six months of 2017 also includes withholding taxes and deemed profit taxes that do not directly correlate to ordinary income or loss.

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 $10 million in the next twelve months due to expiration of statutes of limitations, settlements and/or conclusions of tax examinations.

For both the second quarter and the first six months of 2016, we had a tax benefit of $102 million and $203 million, respectively, on a loss before income taxes of $664 million and $1.26 billion, respectively. Our results for the second quarter of 2016 include charges with no significant tax benefit principally related to $75 million of settlement charges, $78 million of bond tender premium, and $84 million of a note adjustment related to our largest customer in Venezuela, partially offset by $52 million of Zubair project gain with no significant tax expense. Our results for the first six months of 2016 include charges with no significant tax benefit principally related to $140 million of settlement charges, $31 million of currency devaluation related to the Angolan kwanza, $78 million of bond tender premium, and $84 million related to a note adjustment for our largest customer in Venezuela.