8.	Income Taxes

The Tax Cuts and Jobs Act (the “Act”) was enacted on December 22, 2017. The Act reduced the U.S. federal corporate tax rate from 35% to 21%, effective January 1, 2018. At June 30, 2018 and December 31, 2017, we had not completed our accounting for the tax effects of enactment of the Act; however, in certain cases, as described below, we made reasonable estimates of the effects and recorded provisional amounts. We will continue to make and refine our calculations as additional analysis is completed. We recognized an income tax benefit of $242 million in the year ended December 31, 2017 associated with the revaluation of our net deferred tax liability. Our provisional estimate of the one-time transition tax resulted in no additional tax expense. Our provisional estimate on Global Intangible Low Taxed Income (“GILTI”), Foreign Derived Intangible Income (“FDII”), Base Erosion and Anti-Abuse Tax (“BEAT”), and IRC Section 163(j) interest limitation do not impact our effective tax rate for the three and six months ended June 30, 2018. The accounting for the tax effects of the Act will be completed in 2018 as provided by the U.S. Securities and Exchange Commission’s SAB No. 118, Income Tax Accounting Implications of the Tax Cuts and Jobs Act.

The effective tax rates for the three and six months ended June 30, 2018 were 16.7% and (24.3)%, respectively, compared to 18.7% and 13.4% for the same periods in 2017. The Company established valuation allowances on deferred tax assets for losses and tax credits generated in each period, which, when applied to losses for the six months ended June 30, 2018 and the three and six months ended June 30, 2017, resulted in lower effective tax rates than the U.S. statutory rate. The negative tax rate for the six months ended June 30, 2018 is the result of net tax expense recorded against a pre-tax loss for the period. For the three months ended June 30, 2018, a reduction in tax reserves and utilization of tax credits were partially offset by valuation allowances established by the company, which, when applied to income resulted in a lower effective tax rate than the US statutory rate. The change in effective tax rate from 2017 to 2018 was also impacted by the decrease in the U.S. federal corporate tax rate from 35% in 2017 to 21% in 2018.

The balance of unrecognized tax benefits at June 30, 2018 was $57 million. The settlement of foreign jurisdiction audits during the year resulted in a $93 million decrease in uncertain tax positions.

For the three and six months ended June 30, 2018, the Company utilized the discrete-period method to compute its interim tax provision due to significant variations in the relationship between income tax expense and pre-tax accounting income or loss. For the three and six months ended June 30 2017, the Company estimated and recorded tax based on a full year effective tax rate.