Income taxes	6 Months Ended
Jun. 30, 2017
Income Tax Disclosure [Abstract]
Income taxes	Income taxes The effective tax rates for the three and six months ended June 30, 2017, were 15.4% and 15.6%, respectively, compared with 15.2% and 15.5%, respectively, for the corresponding periods of the prior year. The effective rates differ from the federal statutory rates primarily as a result of indefinitely invested earnings of our foreign operations. We do not provide for U.S. income taxes on undistributed earnings of our foreign operations that are intended to be invested indefinitely outside the United States. The increase in our effective tax rate for the three months ended June 30, 2017, was due primarily to a prior year benefit associated with tax incentives and lower tax benefits from share-based compensation payments, offset partially by discrete benefits associated with the effective settlement of certain state and federal tax matters. The increase in our effective tax rate for the six months ended June 30, 2017, was due primarily to lower tax benefits from share-based compensation payments, offset partially by discrete benefits associated with the effective settlement of certain state and federal tax matters and favorable tax impacts of changes in the jurisdictional mix of income and expenses. The U.S. territory of Puerto Rico imposes an excise tax on the gross intercompany purchase price of goods and services from our manufacturer in Puerto Rico. The rate is 4% and is effective through December 31, 2027. We account for the excise tax as a manufacturing cost that is capitalized in inventory and expensed in cost of sales when the related products are sold. For U.S. income tax purposes, the excise tax results in foreign tax credits that are generally recognized in our provision for income taxes when the excise tax is incurred. One or more of our legal entities file income tax returns in the U.S. federal jurisdiction, various U.S. state jurisdictions and certain foreign jurisdictions. Our income tax returns are routinely audited by the tax authorities in those jurisdictions. Significant disputes may arise with authorities involving issues of the timing and amount of deductions, the use of tax credits and allocations of income and expenses among various tax jurisdictions because of differing interpretations of tax laws, regulations and the interpretation of the relevant facts. As previously disclosed, on April 12, 2017, we received a Revenue Agent Report (RAR) from the Internal Revenue Service (IRS) for the years 2010, 2011, and 2012. The RAR proposes to make significant adjustments that relate primarily to the allocation of profits between certain of our entities in the United States and the U.S. territory of Puerto Rico. We disagree with the proposed adjustments and are pursuing resolution through the IRS administrative appeals process, which we believe will likely not be concluded within the next 12 months. Final resolution of the IRS audit could have a material impact on our results of operations and cash flows if not resolved favorably, however, we believe our income tax reserves are appropriately provided for all open tax years. We are no longer subject to U.S. federal income tax examinations for years ended on or before December 31, 2009. In addition, we are currently under examination by a number of other state and foreign tax jurisdictions. During the three and six months ended June 30, 2017, the gross amount of our unrecognized tax benefits (UTBs) increased approximately $110 million and $225 million, respectively, as a result of tax positions taken during the current year. The UTB balance decreased approximately $65 million during the second quarter of 2017 due to the effective settlement of certain state and federal tax matters. Substantially all of the UTBs as of June 30, 2017, if recognized, would affect our effective tax rate.

Income taxes

The effective tax rates for the three and six months ended June 30, 2017, were 15.4% and 15.6%, respectively, compared with 15.2% and 15.5%, respectively, for the corresponding periods of the prior year. The effective rates differ from the federal statutory rates primarily as a result of indefinitely invested earnings of our foreign operations. We do not provide for U.S. income taxes on undistributed earnings of our foreign operations that are intended to be invested indefinitely outside the United States.

The increase in our effective tax rate for the three months ended June 30, 2017, was due primarily to a prior year benefit associated with tax incentives and lower tax benefits from share-based compensation payments, offset partially by discrete benefits associated with the effective settlement of certain state and federal tax matters.

The increase in our effective tax rate for the six months ended June 30, 2017, was due primarily to lower tax benefits from share-based compensation payments, offset partially by discrete benefits associated with the effective settlement of certain state and federal tax matters and favorable tax impacts of changes in the jurisdictional mix of income and expenses.

The U.S. territory of Puerto Rico imposes an excise tax on the gross intercompany purchase price of goods and services from our manufacturer in Puerto Rico. The rate is 4% and is effective through December 31, 2027. We account for the excise tax as a manufacturing cost that is capitalized in inventory and expensed in cost of sales when the related products are sold. For U.S. income tax purposes, the excise tax results in foreign tax credits that are generally recognized in our provision for income taxes when the excise tax is incurred.

One or more of our legal entities file income tax returns in the U.S. federal jurisdiction, various U.S. state jurisdictions and certain foreign jurisdictions. Our income tax returns are routinely audited by the tax authorities in those jurisdictions. Significant disputes may arise with authorities involving issues of the timing and amount of deductions, the use of tax credits and allocations of income and expenses among various tax jurisdictions because of differing interpretations of tax laws, regulations and the interpretation of the relevant facts. As previously disclosed, on April 12, 2017, we received a Revenue Agent Report (RAR) from the Internal Revenue Service (IRS) for the years 2010, 2011, and 2012. The RAR proposes to make significant adjustments that relate primarily to the allocation of profits between certain of our entities in the United States and the U.S. territory of Puerto Rico. We disagree with the proposed adjustments and are pursuing resolution through the IRS administrative appeals process, which we believe will likely not be concluded within the next 12 months. Final resolution of the IRS audit could have a material impact on our results of operations and cash flows if not resolved favorably, however, we believe our income tax reserves are appropriately provided for all open tax years. We are no longer subject to U.S. federal income tax examinations for years ended on or before December 31, 2009. In addition, we are currently under examination by a number of other state and foreign tax jurisdictions.

During the three and six months ended June 30, 2017, the gross amount of our unrecognized tax benefits (UTBs) increased approximately $110 million and $225 million, respectively, as a result of tax positions taken during the current year. The UTB balance decreased approximately $65 million during the second quarter of 2017 due to the effective settlement of certain state and federal tax matters. Substantially all of the UTBs as of June 30, 2017, if recognized, would affect our effective tax rate.