Income Taxes	9 Months Ended
Sep. 30, 2018
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The provision for income taxes reflects an estimated annual tax rate of 24 percent in the third quarter of 2018, compared with 30 percent in the third quarter of 2017. The decrease in the estimated annual tax rate is primarily due to the reduction in the U.S. corporate tax rate beginning January 1, 2018, along with changes in the geographic mix of profits. In addition, a one-time only tax benefit of $7 million was recorded in the third quarter of 2018 for the write-down of net deferred tax liabilities resulting from the 2017 tax year return to provision adjustments. The write-down reflects the reduction in the U.S. corporate tax rate from 35 percent to 21 percent beginning January 1, 2018. Our analysis of U.S. tax reform legislation, updated through September 30, 2018, resulted in no other changes to the 2017 year-end provisional charge. We will continue to update our calculations as additional required information is prepared and analyzed, interpretations and assumptions are refined, and additional guidance is issued. These updates could significantly impact the provision for income taxes, the amount of taxes payable and the deferred tax asset and liability balances. We account for the new U.S. tax on global intangible low-taxed income as a period cost.

Income Taxes

The provision for income taxes reflects an estimated annual tax rate of 24 percent in the third quarter of 2018, compared with 30 percent in the third quarter of 2017. The decrease in the estimated annual tax rate is primarily due to the reduction in the U.S. corporate tax rate beginning January 1, 2018, along with changes in the geographic mix of profits. In addition, a one-time only tax benefit of $7 million was recorded in the third quarter of 2018 for the write-down of net deferred tax liabilities resulting from the 2017 tax year return to provision adjustments. The write-down reflects the reduction in the U.S. corporate tax rate from 35 percent to 21 percent beginning January 1, 2018.

Our analysis of U.S. tax reform legislation, updated through September 30, 2018, resulted in no other changes to the 2017 year-end provisional charge. We will continue to update our calculations as additional required information is prepared and analyzed, interpretations and assumptions are refined, and additional guidance is issued. These updates could significantly impact the provision for income taxes, the amount of taxes payable and the deferred tax asset and liability balances. We account for the new U.S. tax on global intangible low-taxed income as a period cost.