Income taxes	6 Months Ended
Jun. 30, 2016
Income Tax Disclosure [Abstract]
Income taxes	Income taxes The effective tax rates for the three and six months ended June 30, 2016, were 15.2% and 15.5%, respectively, compared with 17.2% and 15.4% 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 decrease in our effective tax rate for the three months ended June 30, 2016, was due primarily to the favorable tax impact of discrete benefits associated with tax incentives and the adoption of a new accounting standard that amends certain aspects of the accounting for employee share-based compensation payments. One aspect of the standard requires that excess tax benefits and deficiencies that arise upon vesting or exercise of share-based payments be recognized as income tax benefits and expenses in the income statement. The decrease was offset partially by the unfavorable tax impact of the changes in the jurisdictional mix of income and expenses. The increase in our effective tax rate for the six months ended June 30, 2016, was due primarily to the unfavorable tax impact of changes in the jurisdictional mix of income and expenses and by a state tax audit settlement in the three months ended March 31, 2015. The increase was offset partially by discrete benefits associated with tax incentives and the adoption of a new accounting standard that amends certain aspects of the accounting for employee share-based compensation payments. 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 six months ended June 30, 2016, the gross amount of our unrecognized tax benefits (UTBs) increased by approximately $110 million and $220 million, respectively, as a result of tax positions taken during the current year. Substantially all of the UTBs as of June 30, 2016, if recognized, would affect our effective tax rate.

Income taxes

The effective tax rates for the three and six months ended June 30, 2016, were 15.2% and 15.5%, respectively, compared with 17.2% and 15.4% 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 decrease in our effective tax rate for the three months ended June 30, 2016, was due primarily to the favorable tax impact of discrete benefits associated with tax incentives and the adoption of a new accounting standard that amends certain aspects of the accounting for employee share-based compensation payments. One aspect of the standard requires that excess tax benefits and deficiencies that arise upon vesting or exercise of share-based payments be recognized as income tax benefits and expenses in the income statement. The decrease was offset partially by the unfavorable tax impact of the changes in the jurisdictional mix of income and expenses.

The increase in our effective tax rate for the six months ended June 30, 2016, was due primarily to the unfavorable tax impact of changes in the jurisdictional mix of income and expenses and by a state tax audit settlement in the three months ended March 31, 2015. The increase was offset partially by discrete benefits associated with tax incentives and the adoption of a new accounting standard that amends certain aspects of the accounting for employee share-based compensation payments.

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 six months ended June 30, 2016, the gross amount of our unrecognized tax benefits (UTBs) increased by approximately $110 million and $220 million, respectively, as a result of tax positions taken during the current year. Substantially all of the UTBs as of June 30, 2016, if recognized, would affect our effective tax rate.