Income Taxes	9 Months Ended
Sep. 30, 2019
Income Tax Disclosure [Abstract]
Income Taxes	NOTE 10: INCOME TAXES Each interim period is considered an integral part of the annual period and, accordingly, we measure our income tax expense using an estimated annual effective tax rate. An enterprise is required, at the end of each interim reporting period, to make its best estimate of the annual effective tax rate for the full fiscal year and use that rate to provide for income taxes on a current year-to-date basis, as adjusted for discrete taxable events that occur during the interim period. The Tax Cuts and Jobs Act of 2017 (the “2017 Tax Act”) introduced significant changes to U.S. income tax law. Changes include, but are not limited to, a corporate tax rate decrease from 35% to 21% effective for tax years beginning after December 31, 2017, the transition of U.S. international taxation from a worldwide tax system to a territorial system, and a one-time tax on the mandatory deemed repatriation of cumulative foreign earnings (the “Transition Tax”) as of December 31, 2017. Our effective tax rate for the three and nine months ended September 30, 2019 was 31.5% and 36.4%, respectively. Our effective tax rate for the three and nine months ended September 30, 2018 was 20.7% and 30.0%, respectively. The change in our effective tax rate during the three months ended September 30, 2019, when compared to the same period in 2018, was primarily due to changes in foreign valuation allowances, a lower benefit from the recognition of excess tax benefits of stock-based compensation, and a change in the relative mix of pretax income among jurisdictions. The change in our effective tax rate during the nine months ended September 30, 2019, when compared to the same period in 2018, was primarily due to the recognition in the second quarter of 2019 of a cumulative income tax expense of $15 million related to the cumulative benefit taken for excluding stock-based compensation from our inter-company cost-sharing arrangements (refer to the discussion below of Altera Corporation (“Altera”) litigation with the Internal Revenue Service (“IRS”) for more information regarding this adjustment), offset by a higher benefit from the recognition of excess tax benefits of stock-based compensation. Our policy is to recognize accrued interest and penalties related to unrecognized tax benefits and income tax liabilities as part of our income tax expense. As of September 30, 2019, we had an accrued interest liability of $19 million, net of federal and state benefit, and no penalties have been accrued. By virtue of consolidated income tax returns previously filed with Expedia, we are currently under an IRS audit for the 2009, 2010 and short-period 2011 tax years. We are separately under examination by the IRS for the short-period 2011 and 2012-2016 tax years, under an employment tax audit by the IRS for the 2013 and 2014 tax years, and have various ongoing audits for state income tax returns. These audits include questioning of the timing and the amount of income and deductions and the allocation of income among various tax jurisdictions. These examinations may lead to proposed or ordinary course adjustments to our taxes. We are no longer subject to tax examinations by tax authorities for years prior to 2009. As of September 30, 2019, no material assessments have resulted, except as noted below regarding our 2009, 2010, and 2011 IRS audit with Expedia and our 2012 and 2013 standalone IRS audit. In January 2017 and April 2019, as part of the IRS audit of Expedia, we received Notices of Proposed Adjustment from the IRS for the 2009, 2010, and 2011 tax years. Subsequently, in September 2019, as part of TripAdvisor’s standalone audit, we received Notices of Proposed Adjustment from the IRS for the 2012 and 2013 tax years. These proposed adjustments are related to certain transfer pricing arrangements with our foreign subsidiaries, and would result in an increase to our worldwide income tax expense in an estimated range of $50 million to $55 million at the close of the audit if the IRS prevails, after consideration of competent authority relief, exclusive of interest and penalties and potential reductions in transition tax, as part of the 2017 Tax Act, which could be significant. We disagree with the proposed adjustments and we intend to defend our position through applicable administrative and, if necessary, judicial remedies. Our policy is to review and update tax reserves as facts and circumstances change. Based on our interpretation of the regulations and available case law, we believe the position we have taken with regard to transfer pricing with our foreign subsidiaries is sustainable. In addition to the risk of additional tax for 2009 through 2013 transactions, if the IRS were to seek transfer pricing adjustments of a similar nature for transactions in subsequent years, we would be subject to significant additional tax liabilities. In July 2015, the United States Tax Court (the “Court”) issued an opinion favorable to Altera with respect to Altera’s litigation with the IRS. This opinion was submitted as a final decision under Tax Court Rule 155 during December 2015. The litigation relates to the treatment of stock-based compensation expense in an inter-company cost-sharing arrangement with Altera’s foreign subsidiary. In its opinion, the Court accepted Altera’s position of excluding stock-based compensation from its inter-company cost-sharing arrangement. The IRS appealed the Court decision on February 19, 2016. On June 7, 2019, a three-judge panel from the Ninth Circuit Court of Appeals reversed the Court’s decision and upheld the validity of the Treasury regulation (Reg. sec. 1.482-7A(d)(2)) requiring stock-based compensation costs to be included in the costs shared in a cost-sharing arrangement. Based on this Ninth Circuit Court of Appeals decision, we recorded a cumulative income tax expense of $15 million during the three months ended June 30, 2019, which was a reversal of income tax benefits taken by the Company since the Court’s 2015 opinion. On July 22, 2019, Altera requested a rehearing before the full Ninth Circuit. As a result, the final outcome of the case is uncertain. If the June 7, 2019 Ninth Circuit Court of Appeals decision is reversed, we would anticipate recording an income tax benefit at that time. The Company will continue to monitor this matter and related potential impacts to its consolidated financial statements.

Income Taxes

9 Months Ended

Sep. 30, 2019

NOTE 10: INCOME TAXES

Each interim period is considered an integral part of the annual period and, accordingly, we measure our income tax expense using an estimated annual effective tax rate. An enterprise is required, at the end of each interim reporting period, to make its best estimate of the annual effective tax rate for the full fiscal year and use that rate to provide for income taxes on a current year-to-date basis, as adjusted for discrete taxable events that occur during the interim period.

The Tax Cuts and Jobs Act of 2017 (the “2017 Tax Act”) introduced significant changes to U.S. income tax law. Changes include, but are not limited to, a corporate tax rate decrease from 35% to 21% effective for tax years beginning after December 31, 2017, the transition of U.S. international taxation from a worldwide tax system to a territorial system, and a one-time tax on the mandatory deemed repatriation of cumulative foreign earnings (the “Transition Tax”) as of December 31, 2017.

Our effective tax rate for the three and nine months ended September 30, 2019 was 31.5% and 36.4%, respectively. Our effective tax rate for the three and nine months ended September 30, 2018 was 20.7% and 30.0%, respectively. The change in our effective tax rate during the three months ended September 30, 2019, when compared to the same period in 2018, was primarily due to changes in foreign valuation allowances, a lower benefit from the recognition of excess tax benefits of stock-based compensation, and a change in the relative mix of pretax income among jurisdictions. The change in our effective tax rate during the nine months ended September 30, 2019, when compared to the same period in 2018, was primarily due to the recognition in the second quarter of 2019 of a cumulative income tax expense of $15 million related to the cumulative benefit taken for excluding stock-based compensation from our inter-company cost-sharing arrangements (refer to the discussion below of Altera Corporation (“Altera”) litigation with the Internal Revenue Service (“IRS”) for more information regarding this adjustment), offset by a higher benefit from the recognition of excess tax benefits of stock-based compensation.

Our policy is to recognize accrued interest and penalties related to unrecognized tax benefits and income tax liabilities as part of our income tax expense. As of September 30, 2019, we had an accrued interest liability of $19 million, net of federal and state benefit, and no penalties have been accrued.

By virtue of consolidated income tax returns previously filed with Expedia, we are currently under an IRS audit for the 2009, 2010 and short-period 2011 tax years. We are separately under examination by the IRS for the short-period 2011 and 2012-2016 tax years, under an employment tax audit by the IRS for the 2013 and 2014 tax years, and have various ongoing audits for state income tax returns. These audits include questioning of the timing and the amount of income and deductions and the allocation of income among various tax jurisdictions. These examinations may lead to proposed or ordinary course adjustments to our taxes. We are no longer subject to tax examinations by tax authorities for years prior to 2009. As of September 30, 2019, no material assessments have resulted, except as noted below regarding our 2009, 2010, and 2011 IRS audit with Expedia and our 2012 and 2013 standalone IRS audit.

In January 2017 and April 2019, as part of the IRS audit of Expedia, we received Notices of Proposed Adjustment from the IRS for the 2009, 2010, and 2011 tax years. Subsequently, in September 2019, as part of TripAdvisor’s standalone audit, we received Notices of Proposed Adjustment from the IRS for the 2012 and 2013 tax years. These proposed adjustments are related to certain transfer pricing arrangements with our foreign subsidiaries, and would result in an increase to our worldwide income tax expense in an estimated range of $50 million to $55 million at the close of the audit if the IRS prevails, after consideration of competent authority relief, exclusive of interest and penalties and potential reductions in transition tax, as part of the 2017 Tax Act, which could be significant. We disagree with the proposed adjustments and we intend to defend our position through applicable administrative and, if necessary, judicial remedies. Our policy is to review and update tax reserves as facts and circumstances change. Based on our interpretation of the regulations and available case law, we believe the position we have taken with regard to transfer pricing with our foreign subsidiaries is sustainable. In addition to the risk of additional tax for 2009 through 2013 transactions, if the IRS were to seek transfer pricing adjustments of a similar nature for transactions in subsequent years, we would be subject to significant additional tax liabilities.

In July 2015, the United States Tax Court (the “Court”) issued an opinion favorable to Altera with respect to Altera’s litigation with the IRS. This opinion was submitted as a final decision under Tax Court Rule 155 during December 2015. The litigation relates to the treatment of stock-based compensation expense in an inter-company cost-sharing arrangement with Altera’s foreign subsidiary. In its opinion, the Court accepted Altera’s position of excluding stock-based compensation from its inter-company cost-sharing

arrangement. The IRS appealed the Court decision on February 19, 2016. On June 7, 2019, a three-judge panel from the Ninth Circuit Court of Appeals reversed the Court’s decision and upheld the validity of the Treasury regulation (Reg. sec. 1.482-7A(d)(2)) requiring stock-based compensation costs to be included in the costs shared in a cost-sharing arrangement. Based on this Ninth Circuit Court of Appeals decision, we recorded a cumulative income tax expense of $15 million during the three months ended June 30, 2019, which was a reversal of income tax benefits taken by the Company since the Court’s 2015 opinion. On July 22, 2019, Altera requested a rehearing before the full Ninth Circuit. As a result, the final outcome of the case is uncertain. If the June 7, 2019 Ninth Circuit Court of Appeals decision is reversed, we would anticipate recording an income tax benefit at that time. The Company will continue to monitor this matter and related potential impacts to its consolidated financial statements.