Income taxes	9 Months Ended
Sep. 30, 2016
Income Tax Disclosure [Abstract]
Income taxes	Income taxes The effective tax rates for the three and nine months ended September 30, 2016, were 16.6% and 15.9%, respectively, compared with 15.0% and 15.3% 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 September 30, 2016, was due primarily to the unfavorable tax impact of changes in the jurisdictional mix of income and expenses. The increase in our effective tax rate for the nine months ended September 30, 2016, was due primarily to the unfavorable tax impact of changes in the jurisdictional mix of income and expenses and a state tax audit settlement in the prior year. The increase was offset partially by the adoption of a new accounting standard that amends certain aspects of the accounting for employee share-based compensation payments and discrete benefits associated with tax incentives. 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 4.0% effective through December 31, 2017. 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 these tax 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 and regulations. We are no longer subject to U.S. federal income tax examinations for years ended on or before December 31, 2009, or to California state income tax examinations for years ended on or before December 31, 2008. We are currently under audit in several jurisdictions, including a U.S. federal income tax examination for tax years ended December 31, 2010, 2011 and 2012. Tax audits can involve complex issues, interpretations and judgments; and their resolution can take many years, particularly if subject to negotiation or litigation. Our assessments of uncertain tax benefits are based on information available to us at this time, including estimates and assumptions that have been deemed appropriate by management but may not be representative of final audit resolutions. During the three and nine months ended September 30, 2016, the gross amount of our unrecognized tax benefits (UTBs) increased by approximately $115 million and $335 million, respectively, as a result of tax positions taken during the current year. Substantially all of the UTBs as of September 30, 2016, if recognized, would affect our effective tax rate.

Income taxes

The effective tax rates for the three and nine months ended September 30, 2016, were 16.6% and 15.9%, respectively, compared with 15.0% and 15.3% 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 September 30, 2016, was due primarily to the unfavorable tax impact of changes in the jurisdictional mix of income and expenses.

The increase in our effective tax rate for the nine months ended September 30, 2016, was due primarily to the unfavorable tax impact of changes in the jurisdictional mix of income and expenses and a state tax audit settlement in the prior year. The increase was offset partially by the adoption of a new accounting standard that amends certain aspects of the accounting for employee share-based compensation payments and discrete benefits associated with tax incentives.

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 4.0% effective through December 31, 2017. 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 these tax 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 and regulations.

We are no longer subject to U.S. federal income tax examinations for years ended on or before December 31, 2009, or to California state income tax examinations for years ended on or before December 31, 2008. We are currently under audit in several jurisdictions, including a U.S. federal income tax examination for tax years ended December 31, 2010, 2011 and 2012. Tax audits can involve complex issues, interpretations and judgments; and their resolution can take many years, particularly if subject to negotiation or litigation. Our assessments of uncertain tax benefits are based on information available to us at this time, including estimates and assumptions that have been deemed appropriate by management but may not be representative of final audit resolutions.

During the three and nine months ended September 30, 2016, the gross amount of our unrecognized tax benefits (UTBs) increased by approximately $115 million and $335 million, respectively, as a result of tax positions taken during the current year. Substantially all of the UTBs as of September 30, 2016, if recognized, would affect our effective tax rate.