Income Taxes	3 Months Ended
Mar. 31, 2019
Income Tax Disclosure [Abstract]
Income Taxes	12. Income Taxes We operate on a global basis and are subject to numerous and complex tax laws and regulations. Additionally, tax laws continue to undergo rapid changes in both application and interpretation by various countries, including state aid interpretations and initiatives led by the Organization for Economic Cooperation and Development. Our income tax filings are subject to examinations by taxing authorities throughout the world. Income tax audits may require an extended period of time to reach resolution and may result in significant income tax adjustments when interpretation of tax laws or allocation of company profits is disputed. Although ultimate timing is uncertain, the net amount of tax liability for unrecognized tax benefits may change within the next twelve months due to changes in audit status, expiration of statutes of limitations, settlements of tax assessments and other events. Management’s best estimate of such change is within the range of a $180 million decrease to a $25 million increase. Our U.S. Federal income tax returns have been audited through 2009 and are currently under audit for years 2010-2015. The IRS has proposed adjustments for years 2005-2012, reallocating profits between certain of our U.S. and foreign subsidiaries. We have disputed these adjustments and intend to continue to vigorously defend our positions. For years 2005-2007 and 2008-2009, we have filed petitions with the U.S. Tax Court. For years 2010-2012, we are pursuing resolution through the IRS Administrative Appeals Process. In the three month periods ended March 31, 2019 and 2018, our effective tax rate (“ETR”) was 15.6 percent and 21.1 percent, respectively. The decline in ETR from the prior year was primarily from a release of uncertain tax positions due to emerging foreign tax guidance in the first quarter. Absent discrete tax events, we expect our future ETR will continue to be lower than the U.S. corporate income tax rate of 21.0 percent due to our mix of earnings between U.S. and foreign locations which have lower corporate income tax rates. Our ETR in future periods could also potentially be impacted by changes in our mix of pre-tax earnings; changes in tax rates, tax laws or their interpretation, including the European Union rules on state aid; the outcome of various federal, state and foreign audits; and the expiration of certain statutes of limitations. Currently, we cannot reasonably estimate the impact of these items on our financial results.

Income Taxes

3 Months Ended

Mar. 31, 2019

12. Income Taxes

We operate on a global basis and are subject to numerous and complex tax laws and regulations. Additionally, tax laws continue to undergo rapid changes in both application and interpretation by various countries, including state aid interpretations and initiatives led by the Organization for Economic Cooperation and Development. Our income tax filings are subject to examinations by taxing authorities throughout the world. Income tax audits may require an extended period of time to reach resolution and may result in significant income tax adjustments when interpretation of tax laws or allocation of company profits is disputed. Although ultimate timing is uncertain, the net amount of tax liability for unrecognized tax benefits may change within the next twelve months due to changes in audit status, expiration of statutes of limitations, settlements of tax assessments and other events. Management’s best estimate of such change is within the range of a $180 million decrease to a $25 million increase.

Our U.S. Federal income tax returns have been audited through 2009 and are currently under audit for years 2010-2015. The IRS has proposed adjustments for years 2005-2012, reallocating profits between certain of our U.S. and foreign subsidiaries. We have disputed these adjustments and intend to continue to vigorously defend our positions. For years 2005-2007 and 2008-2009, we have filed petitions with the U.S. Tax Court. For years 2010-2012, we are pursuing resolution through the IRS Administrative Appeals Process.

In the three month periods ended March 31, 2019 and 2018, our effective tax rate (“ETR”) was 15.6 percent and 21.1 percent, respectively. The decline in ETR from the prior year was primarily from a release of uncertain tax positions due to emerging foreign tax guidance in the first quarter. Absent discrete tax events, we expect our future ETR will continue to be lower than the U.S. corporate income tax rate of 21.0 percent due to our mix of earnings between U.S. and foreign locations which have lower corporate income tax rates. Our ETR in future periods could also potentially be impacted by changes in our mix of pre-tax earnings; changes in tax rates, tax laws or their interpretation, including the European Union rules on state aid; the outcome of various federal, state and foreign audits; and the expiration of certain statutes of limitations. Currently, we cannot reasonably estimate the impact of these items on our financial results.