Income Taxes	9 Months Ended
Sep. 30, 2018
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 third quarter and the nine months ended September 30, 2018, we have 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 continue to use this method each quarter until the annual effective tax rate method is deemed appropriate. For the third quarter and the first nine months of 2018, we had a tax expense of $22 million and $80 million, respectively, on a loss before income taxes of $172 million and $615 million, respectively. Results for the third quarter and the first nine months of 2018 include losses with no significant tax benefit. The tax expense for the third quarter and the first nine months of 2018 also includes withholding taxes and deemed profit taxes that do not directly correlate to ordinary income or loss. On December 22, 2017, the U.S. enacted into law a comprehensive tax reform bill (the “Tax Cuts and Jobs Act,” or “TCJA”). The TCJA significantly revises the U.S. corporate income tax by, among other things, lowering the statutory corporate tax rate from 35% to 21%, eliminating certain deductions, imposing a mandatory one-time tax on accumulated earnings of foreign subsidiaries as of 2017 held in cash and illiquid assets (with the latter taxed at a lower rate), and a shift of the U.S. taxation of multinational corporations from a tax on worldwide income to a partial territorial system (along with certain rules designed to prevent erosion of the U.S. income tax base, such as the base erosion and anti-abuse tax). The SEC has issued guidance that allows for a measurement period of up to one year after the enactment date of the legislation to finalize the recording of the related tax impacts. In the fourth quarter of 2017, the Company did not have all the necessary information to analyze all effects of this tax reform; as a result, we recorded a provisional amount which we believe represents a reasonable estimate of the accounting implications of this tax reform. In addition, the various impacts of the TCJA may differ from the estimated impacts recognized in the fourth quarter due to regulatory guidance that may be issued in the future, tax law technical corrections, refined computations, and possible changes in the Company’s interpretations, assumptions, and actions as a result of the tax legislation. No adjustment to the provisional amount has been identified in the nine months of 2018 and we do not expect a material change to the provision in the fourth quarter. We will continue to monitor and assess additional guidance that may be issued in the fourth quarter which may impact our estimate. 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 $19 million in the next twelve months due to expiration of statutes of limitations, settlements and/or conclusions of tax examinations. For the third quarter and the first nine months of 2017, we had a tax expense of $25 million and $75 million, respectively, on a loss before income taxes of $226 million and $784 million, respectively. Results for the third quarter and the first nine months of 2017 include losses with no significant tax benefit. The tax expense for the third quarter and the first nine months of 2017 also included withholding taxes, minimum taxes and deemed profit taxes that do not directly correlate to ordinary income or loss.

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 third quarter and the nine months ended September 30, 2018, we have 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 continue to use this method each quarter until the annual effective tax rate method is deemed appropriate. For the third quarter and the first nine months of 2018, we had a tax expense of $22 million and $80 million, respectively, on a loss before income taxes of $172 million and $615 million, respectively. Results for the third quarter and the first nine months of 2018 include losses with no significant tax benefit. The tax expense for the third quarter and the first nine months of 2018 also includes withholding taxes and deemed profit taxes that do not directly correlate to ordinary income or loss.

On December 22, 2017, the U.S. enacted into law a comprehensive tax reform bill (the “Tax Cuts and Jobs Act,” or “TCJA”). The TCJA significantly revises the U.S. corporate income tax by, among other things, lowering the statutory corporate tax rate from 35% to 21%, eliminating certain deductions, imposing a mandatory one-time tax on accumulated earnings of foreign subsidiaries as of 2017 held in cash and illiquid assets (with the latter taxed at a lower rate), and a shift of the U.S. taxation of multinational corporations from a tax on worldwide income to a partial territorial system (along with certain rules designed to prevent erosion of the U.S. income tax base, such as the base erosion and anti-abuse tax). The SEC has issued guidance that allows for a measurement period of up to one year after the enactment date of the legislation to finalize the recording of the related tax impacts. In the fourth quarter of 2017, the Company did not have all the necessary information to analyze all effects of this tax reform; as a result, we recorded a provisional amount which we believe represents a reasonable estimate of the accounting implications of this tax reform. In addition, the various impacts of the TCJA may differ from the estimated impacts recognized in the fourth quarter due to regulatory guidance that may be issued in the future, tax law technical corrections, refined computations, and possible changes in the Company’s interpretations, assumptions, and actions as a result of the tax legislation. No adjustment to the provisional amount has been identified in the nine months of 2018 and we do not expect a material change to the provision in the fourth quarter. We will continue to monitor and assess additional guidance that may be issued in the fourth quarter which may impact our estimate.

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 $19 million in the next twelve months due to expiration of statutes of limitations, settlements and/or conclusions of tax examinations.

For the third quarter and the first nine months of 2017, we had a tax expense of $25 million and $75 million, respectively, on a loss before income taxes of $226 million and $784 million, respectively. Results for the third quarter and the first nine months of 2017 include losses with no significant tax benefit. The tax expense for the third quarter and the first nine months of 2017 also included withholding taxes, minimum taxes and deemed profit taxes that do not directly correlate to ordinary income or loss.