Income Taxes	3 Months Ended
Mar. 31, 2018
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES Our tax provision or benefit from income taxes for interim periods is determined using an estimate of our annual effective tax rate, adjusted for discrete items, if any, that are taken into account in the relevant period. Each quarter we update our estimate of the annual effective tax rate, and if our estimated tax rate changes, we make a cumulative adjustment. Our quarterly tax provision, and our quarterly estimate of our annual effective tax rate, is subject to significant variation due to several factors, including variability in accurately predicting our pre-tax and taxable income and loss and the mix of jurisdictions to which they relate, intercompany transactions, the applicability of special tax regimes, changes in how we do business, acquisitions (including integrations) and investments, audit-related developments, changes in our stock price, changes in our deferred tax assets and liabilities and their valuation, foreign currency gains (losses), changes in statutes, regulations, case law, and administrative practices, principles, and interpretations related to tax, accounting, and other areas, including European Union state aid rules, and relative changes of expenses or losses for which tax benefits are not recognized. Additionally, our effective tax rate can be more or less volatile based on the amount of pre-tax income or loss. For example, the impact of discrete items and non-deductible expenses on our effective tax rate is greater when our pre-tax income is lower. The 2017 Tax Act was signed into law on December 22, 2017. The 2017 Tax Act significantly revised the U.S. corporate income tax by, among other things, lowering the statutory corporate tax rate from 35% to 21%, eliminating certain deductions, imposing a mandatory one-time tax on accumulated earnings of foreign subsidiaries, introducing new tax regimes, and changing how foreign earnings are subject to U.S. tax. The 2017 Tax Act also enhanced and extended through 2026 the option to claim accelerated depreciation deductions on qualified property. We have not completed our determination of the accounting implications of the 2017 Tax Act on our tax accruals. However, we have reasonably estimated the effects of the 2017 Tax Act and recorded provisional amounts in our financial statements as of December 31, 2017. We recorded a provisional tax benefit for the impact of the 2017 Tax Act of approximately $789 million. This amount was primarily comprised of the remeasurement of federal net deferred tax liabilities resulting from the permanent reduction in the U.S. statutory corporate tax rate to 21% from 35%, after taking into account the mandatory one-time tax on the accumulated earnings of our foreign subsidiaries. The amount of this one-time tax is not material. As we complete our analysis of the 2017 Tax Act, collect and prepare necessary data, and interpret any additional guidance issued by the U.S. Treasury Department, the IRS, and other standard-setting bodies, we may make adjustments to the provisional amounts. Those adjustments may materially impact our provision for income taxes in the period in which the adjustments are made. For 2018, we estimate that our effective tax rate will be favorably affected by the impact of excess tax benefits from stock-based compensation and the U.S. federal research and development credit and adversely affected by losses incurred in certain foreign jurisdictions for which we may not realize a tax benefit. Losses for which we may not realize a related tax benefit, primarily due to losses of foreign subsidiaries, reduce our pre-tax income without a corresponding reduction in our tax expense, and therefore increase our effective tax rate. We record valuation allowances against the deferred tax assets associated with losses for which we may not realize a related tax benefit. Our income tax provision for the three months ended March 31, 2017 was $229 million, which included $122 million of net discrete tax benefits primarily attributable to excess tax benefits from stock-based compensation, partially offset by the estimated impact of audit-related developments. Our income tax provision for the three months ended March 31, 2018 was $287 million, which included $368 million of net discrete tax benefits primarily attributable to excess tax benefits from stock-based compensation. Cash paid for income taxes, net of refunds was $246 million and $513 million in Q1 2017 and Q1 2018. As of December 31, 2017 and March 31, 2018, tax contingencies were $2.3 billion and $2.6 billion. We expect the total amount of tax contingencies will grow in 2018. In addition, changes in state, federal, and foreign tax laws may increase our tax contingencies. The timing of the resolution of income tax examinations is highly uncertain, and the amounts ultimately paid, if any, upon resolution of the issues raised by the taxing authorities may differ from the amounts accrued. It is reasonably possible that within the next 12 months we will receive additional assessments by various tax authorities or possibly reach resolution of income tax examinations in one or more jurisdictions. These assessments or settlements could result in changes to our contingencies related to positions on tax filings on prior years’ tax filings. We are under examination, or may be subject to examination, by the Internal Revenue Service (“IRS”) for the calendar year 2005 and thereafter. These examinations may lead to ordinary course adjustments or proposed adjustments to our taxes or our net operating losses with respect to years under examination as well as subsequent periods. As previously disclosed, we have received Notices of Proposed Adjustment (“NOPAs”) from the IRS for transactions undertaken in the 2005 and 2006 calendar years relating to transfer pricing with our foreign subsidiaries. The IRS is seeking to increase our U.S. taxable income by an amount that would result in additional federal tax of approximately $1.5 billion, subject to interest. On March 23, 2017, the U.S. Tax Court issued its decision regarding the issues raised in the IRS NOPAs. The Tax Court rejected the approach from the IRS NOPAs in determining transfer pricing adjustments in 2005 and 2006 for the transactions undertaken with our foreign subsidiaries and adopted, with adjustments, our suggested approach. In September 2017, the IRS appealed the decision to the U.S. Court of Appeals for the Ninth Circuit. We will continue to defend ourselves vigorously in this matter. If the Tax Court decision were reversed on appeal or if the IRS were to successfully assert transfer pricing adjustments of a similar nature to the NOPAs for transactions in subsequent years, we could be subject to significant additional tax liabilities. In October 2014, the European Commission opened a formal investigation to examine whether decisions by the tax authorities in Luxembourg with regard to the corporate income tax paid by certain of our subsidiaries comply with European Union rules on state aid. On October 4, 2017, the European Commission announced its decision that determinations by the tax authorities in Luxembourg did not comply with European Union rules on state aid. Based on that decision the European Commission announced an estimated recovery amount of approximately €250 million, plus interest, for the period May 2006 through June 2014, and ordered Luxembourg tax authorities to calculate the actual amount of additional taxes subject to recovery. Luxembourg computed an initial recovery amount, consistent with the European Commission’s decision, that we deposited into escrow in March 2018, subject to adjustment pending conclusion of all appeals. In December 2017, Luxembourg appealed the European Commission’s decision. We believe the European Commission’s decision to be without merit and will consider our legal options, including an appeal. We are also subject to taxation in various states and other foreign jurisdictions including Canada, China, Germany, India, Japan, Luxembourg, and the United Kingdom. We are under, or may be subject to, audit or examination and additional assessments by the relevant authorities in respect of these particular jurisdictions primarily for 2008 and thereafter.

INCOME TAXES

Our tax provision or benefit from income taxes for interim periods is determined using an estimate of our annual effective tax rate, adjusted for discrete items, if any, that are taken into account in the relevant period. Each quarter we update our estimate of the annual effective tax rate, and if our estimated tax rate changes, we make a cumulative adjustment.

Our quarterly tax provision, and our quarterly estimate of our annual effective tax rate, is subject to significant variation due to several factors, including variability in accurately predicting our pre-tax and taxable income and loss and the mix of jurisdictions to which they relate, intercompany transactions, the applicability of special tax regimes, changes in how we do business, acquisitions (including integrations) and investments, audit-related developments, changes in our stock price, changes in our deferred tax assets and liabilities and their valuation, foreign currency gains (losses), changes in statutes, regulations, case law, and administrative practices, principles, and interpretations related to tax, accounting, and other areas, including European Union state aid rules, and relative changes of expenses or losses for which tax benefits are not recognized. Additionally, our effective tax rate can be more or less volatile based on the amount of pre-tax income or loss. For example, the impact of discrete items and non-deductible expenses on our effective tax rate is greater when our pre-tax income is lower.

The 2017 Tax Act was signed into law on December 22, 2017. The 2017 Tax Act significantly revised the U.S. corporate income tax by, among other things, lowering the statutory corporate tax rate from 35% to 21%, eliminating certain deductions, imposing a mandatory one-time tax on accumulated earnings of foreign subsidiaries, introducing new tax regimes, and changing how foreign earnings are subject to U.S. tax. The 2017 Tax Act also enhanced and extended through 2026 the option to claim accelerated depreciation deductions on qualified property. We have not completed our determination of the accounting implications of the 2017 Tax Act on our tax accruals. However, we have reasonably estimated the effects of the 2017 Tax Act and recorded provisional amounts in our financial statements as of December 31, 2017. We recorded a provisional tax benefit for the impact of the 2017 Tax Act of approximately $789 million. This amount was primarily comprised of the remeasurement of federal net deferred tax liabilities resulting from the permanent reduction in the U.S. statutory corporate tax rate to 21% from 35%, after taking into account the mandatory one-time tax on the accumulated earnings of our foreign subsidiaries. The amount of this one-time tax is not material. As we complete our analysis of the 2017 Tax Act, collect and prepare necessary data, and interpret any additional guidance issued by the U.S. Treasury Department, the IRS, and other standard-setting bodies, we may make adjustments to the provisional amounts. Those adjustments may materially impact our provision for income taxes in the period in which the adjustments are made.

For 2018, we estimate that our effective tax rate will be favorably affected by the impact of excess tax benefits from stock-based compensation and the U.S. federal research and development credit and adversely affected by losses incurred in certain foreign jurisdictions for which we may not realize a tax benefit. Losses for which we may not realize a related tax benefit, primarily due to losses of foreign subsidiaries, reduce our pre-tax income without a corresponding reduction in our tax expense, and therefore increase our effective tax rate. We record valuation allowances against the deferred tax assets associated with losses for which we may not realize a related tax benefit.

Our income tax provision for the three months ended March 31, 2017 was $229 million, which included $122 million of net discrete tax benefits primarily attributable to excess tax benefits from stock-based compensation, partially offset by the estimated impact of audit-related developments. Our income tax provision for the three months ended March 31, 2018 was $287 million, which included $368 million of net discrete tax benefits primarily attributable to excess tax benefits from stock-based compensation.

Cash paid for income taxes, net of refunds was $246 million and $513 million in Q1 2017 and Q1 2018.

As of December 31, 2017 and March 31, 2018, tax contingencies were $2.3 billion and $2.6 billion. We expect the total amount of tax contingencies will grow in 2018. In addition, changes in state, federal, and foreign tax laws may increase our tax contingencies. The timing of the resolution of income tax examinations is highly uncertain, and the amounts ultimately paid, if any, upon resolution of the issues raised by the taxing authorities may differ from the amounts accrued. It is reasonably possible that within the next 12 months we will receive additional assessments by various tax authorities or possibly reach resolution of income tax examinations in one or more jurisdictions. These assessments or settlements could result in changes to our contingencies related to positions on tax filings on prior years’ tax filings.

We are under examination, or may be subject to examination, by the Internal Revenue Service (“IRS”) for the calendar year 2005 and thereafter. These examinations may lead to ordinary course adjustments or proposed adjustments to our taxes or our net operating losses with respect to years under examination as well as subsequent periods. As previously disclosed, we have received Notices of Proposed Adjustment (“NOPAs”) from the IRS for transactions undertaken in the 2005 and 2006 calendar years relating to transfer pricing with our foreign subsidiaries. The IRS is seeking to increase our U.S. taxable income by an amount that would result in additional federal tax of approximately $1.5 billion, subject to interest. On March 23, 2017, the U.S. Tax Court issued its decision regarding the issues raised in the IRS NOPAs. The Tax Court rejected the approach from the IRS NOPAs in determining transfer pricing adjustments in 2005 and 2006 for the transactions undertaken with our foreign subsidiaries and adopted, with adjustments, our suggested approach. In September 2017, the IRS appealed the decision to the U.S. Court of Appeals for the Ninth Circuit. We will continue to defend ourselves vigorously in this matter. If the Tax Court decision were reversed on appeal or if the IRS were to successfully assert transfer pricing adjustments of a similar nature to the NOPAs for transactions in subsequent years, we could be subject to significant additional tax liabilities.

In October 2014, the European Commission opened a formal investigation to examine whether decisions by the tax authorities in Luxembourg with regard to the corporate income tax paid by certain of our subsidiaries comply with European Union rules on state aid. On October 4, 2017, the European Commission announced its decision that determinations by the tax authorities in Luxembourg did not comply with European Union rules on state aid. Based on that decision the European Commission announced an estimated recovery amount of approximately €250 million, plus interest, for the period May 2006 through June 2014, and ordered Luxembourg tax authorities to calculate the actual amount of additional taxes subject to recovery. Luxembourg computed an initial recovery amount, consistent with the European Commission’s decision, that we deposited into escrow in March 2018, subject to adjustment pending conclusion of all appeals. In December 2017, Luxembourg appealed the European Commission’s decision. We believe the European Commission’s decision to be without merit and will consider our legal options, including an appeal. We are also subject to taxation in various states and other foreign jurisdictions including Canada, China, Germany, India, Japan, Luxembourg, and the United Kingdom. We are under, or may be subject to, audit or examination and additional assessments by the relevant authorities in respect of these particular jurisdictions primarily for 2008 and thereafter.