Income Taxes	6 Months Ended
Jun. 30, 2018
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes On December 22, 2017, the Tax Act was enacted, which made broad and complex changes to the U.S. tax laws. In particular, the U.S. corporation income tax rate was reduced to 21% from 35%, and a new territorial tax system was implemented that will affect the future U.S. taxation of earnings repatriated from our foreign subsidiaries and affiliates. Other provisions included an immediate deduction for qualified investments and limitations on the deductibility of interest expense and executive compensation. Due to our net operating loss position, these adjustments had no cash impact on our tax positions. In 2017, we recorded a one-time non-cash net tax benefit of $315.9 million, which represented our provisional estimate of the impact of the Tax Act. This amount included a net benefit of $371.4 million associated with the re-measurement of our net deferred tax liability utilizing the lower U.S. tax rate. The Tax Act also imposed a one-time transitional repatriation tax of $57.2 million on certain undistributed earnings of our non-U.S. subsidiaries and affiliates. We continue to evaluate the provisions of the Tax Act, and the ultimate impact may differ from this provisional estimate, due to, among other things, changes in interpretations and assumptions made by us, additional guidance that may be issued by the Internal Revenue Service and the U.S. Department of the Treasury, and actions that we may take. In addition, these estimates may change due to guidance provided by state taxing authorities and the completion of our 2017 U.S. and state income tax returns. No adjustments were made to our initial provisional estimate during the six months ended June 30, 2018. Our effective tax rate was 25% for the six months ended June 30, 2018, compared to 30% for the six months ended June 30, 2017. The difference in the effective rates for the current year compared to the prior year is primarily attributable to the reduction in the U.S. corporation income tax rate from 35% to 21%, as part of the Tax Act. Additionally, the effective tax rate was impacted by the mix of pre-tax income among domestic and foreign jurisdictions, which are taxed at different rates. Incremental tax benefits associated with share-based compensation were also recognized in each of the six-month periods ended June 30, 2018 and 2017.

Income Taxes

On December 22, 2017, the Tax Act was enacted, which made broad and complex changes to the U.S. tax laws. In particular, the U.S. corporation income tax rate was reduced to 21% from 35%, and a new territorial tax system was implemented that will affect the future U.S. taxation of earnings repatriated from our foreign subsidiaries and affiliates. Other provisions included an immediate deduction for qualified investments and limitations on the deductibility of interest expense and executive compensation. Due to our net operating loss position, these adjustments had no cash impact on our tax positions.

In 2017, we recorded a one-time non-cash net tax benefit of $315.9 million, which represented our provisional estimate of the impact of the Tax Act. This amount included a net benefit of $371.4 million associated with the re-measurement of our net deferred tax liability utilizing the lower U.S. tax rate. The Tax Act also imposed a one-time transitional repatriation tax of $57.2 million on certain undistributed earnings of our non-U.S. subsidiaries and affiliates.

We continue to evaluate the provisions of the Tax Act, and the ultimate impact may differ from this provisional estimate, due to, among other things, changes in interpretations and assumptions made by us, additional guidance that may be issued by the Internal Revenue Service and the U.S. Department of the Treasury, and actions that we may take. In addition, these estimates may change due to guidance provided by state taxing authorities and the completion of our 2017 U.S. and state income tax returns. No adjustments were made to our initial provisional estimate during the six months ended June 30, 2018.

Our effective tax rate was 25% for the six months ended June 30, 2018, compared to 30% for the six months ended June 30, 2017. The difference in the effective rates for the current year compared to the prior year is primarily attributable to the reduction in the U.S. corporation income tax rate from 35% to 21%, as part of the Tax Act. Additionally, the effective tax rate was impacted by the mix of pre-tax income among domestic and foreign jurisdictions, which are taxed at different rates. Incremental tax benefits associated with share-based compensation were also recognized in each of the six-month periods ended June 30, 2018 and 2017.