Income Taxes	3 Months Ended
Income Taxes	Mar. 31, 2018
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Our quarterly provision for income taxes is measured using an estimated annual effective tax rate, adjusted for discrete items within periods presented. The comparison of our effective tax rate between periods is significantly impacted by the level and mix of earnings and losses by tax jurisdiction, foreign income tax rate differentials and discrete items. The income tax provision for the three months ended March 31, 2018 was $16 million resulting in an effective tax rate of 17.1%, compared to $14 million resulting in an effective tax rate of 20.4% for the same period in 2017. The effective tax rate was lower than the United States federal statutory rate primarily due to the mix of earnings in jurisdictions in both periods. Additionally, the effective tax rate for the current period is lower than the three month period ended March 31, 2017 due to the reduction of the United States federal corporate tax rate, partially offset by the Global Intangible Low-Taxed Income ("GILTI") inclusion. Unrecognized Tax Benefits We recognize tax benefits from uncertain tax positions only if it is more likely than not that the tax position will be sustained on examination by the taxing authorities, based on the technical merits of the position. The tax benefits recognized in the condensed consolidated financial statements from such positions are measured based on the largest benefit that has a greater than 50% likelihood of being realized upon ultimate settlement. The amount of unrecognized tax benefits at March 31, 2018 was $131 million, as compared to $130 million at December 31, 2017, which if ultimately recognized will reduce our effective tax rate. We do not believe that the unrecognized tax benefits will significantly change within the next twelve months. We classify interest expense relating to unrecognized tax benefits as a component of other non-operating expense, net, and tax penalties as a component of income tax expense in our Condensed Consolidated Income Statements. As of March 31, 2018, we had $4 million of interest accrued for unrecognized tax benefits. Tax Act On December 22, 2017, the U.S. government enacted comprehensive tax legislation commonly referred to as the Tax Cuts and Jobs Act (the “Tax Act”). The Tax Act makes broad and complex changes to the U.S. tax code. The SEC staff issued SAB 118, which provides guidance on accounting for the tax effects of the Tax Act. SAB 118 provides a measurement period that should not extend beyond one year from the Tax Act enactment date for companies to complete the accounting under ASC 740. In accordance with SAB 118, a company must reflect the income tax effects of those aspects of the Tax Act for which the accounting under ASC 740 is complete. To the extent that a company’s accounting for certain income tax effects of the Tax Act is incomplete but it is able to determine a reasonable estimate, it must record a provisional estimate in the financial statements. If a company cannot determine a provisional estimate to be included in the financial statements, it should continue to apply ASC 740 on the basis of the provisions of the tax laws that were in effect immediately before the enactment of the Tax Act. Our accounting for the following elements of the Tax Act is incomplete: reduction of U.S. federal corporate tax rate and Deemed Repatriation Transition Tax ("Transition Tax"). As noted at year end, however, we were able to reasonably estimate certain effects and, therefore, recorded provisional adjustments for reduction of U.S. federal corporate tax rate and Transition Tax as of December 31, 2017. We have not made additional measurement-period adjustments related to the reduction of U.S. federal corporate tax rate during the quarter as we are continuing to perform additional analysis of our deferred tax assets and liabilities. We have not made additional measurement-period adjustments related to the Transition Tax as we are still completing a more detailed analysis of our untaxed accumulated and current earnings and profits ("E&P") as well as awaiting additional regulatory guidance. We are evaluating new guidance issued during the period and expect to complete our accounting within the prescribed measurement period. Because of the complexity of the GILTI tax rules, we are continuing to evaluate this provision of the Act and the application of ASC 740. As noted at year-end, we were not yet able to reasonably estimate the effect of the new GILTI rules. Therefore, no provisional adjustments were recorded as of December 31, 2017. Under U.S. GAAP, we are allowed to make an accounting policy choice of either (1) treating taxes due on future U.S. inclusions in taxable income related to GILTI as a current-period expense when incurred (the “period cost method”) or (2) factoring such amounts into a company’s measurement of its deferred taxes (the “deferred method”). Our selection of an accounting policy related to the new GILTI tax rules will depend, in part, on analyzing our global income to determine whether we expect to have future U.S. inclusions in taxable income related to GILTI and, if so, what the impact is expected to be. Because whether we expect to have future U.S. inclusions in taxable income related to GILTI depends on a number of different aspects of our estimated future results of global operations, we are not yet able to reasonably estimate the long-term effects of this provision of the Tax Act. Therefore, we have not recorded any potential deferred tax effects related to GILTI in our financial statements and have not made a policy decision regarding whether to record deferred taxes on GILTI or use the period cost method. Our accounting for the effects related to GILTI is not complete and we expect to complete our accounting within the prescribed measurement period.