Income Taxes	3 Months Ended
Mar. 31, 2018
Income Tax Disclosure [Abstract]
Income Taxes	NOTE 8: 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. Our effective tax rate for the three months ended March 31, 2018 and 2017 was 76.2% and 48.0%, respectively. For the three months ended March 31, 2018, the effective tax rate was greater than the federal statutory rate primarily due to international provisions from the U.S. Tax Cuts and Jobs Act of 2017 (“2017 Tax Act”), discussed below, foreign valuation allowances, and the income tax effects of the accounting for share based compensation. The change in the effective tax rate for the three months ended March 31, 2018 compared to the three months ended March 31, 2017 rate was primarily due to the Transition Tax, discussed below, and a lower stock price resulting in stock compensation shortfalls. 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. On December 22, 2017, the SEC issued Staff Accounting Bulletin No. 118, or SAB 118, which allows us to record provisional amounts during a measurement period not to extend beyond one year of the enactment date. The measurement period is deemed to have ended earlier when the registrant has obtained, prepared, and analyzed the information necessary to finalize its accounting. During the measurement period, impacts of the law are expected to be recorded at the time a reasonable estimate for all or a portion of the effects can be made, and provisional amounts can be recognized and adjusted as information becomes available, prepared, or analyzed. During the quarter ended March 31, 2018, we recorded an incremental $5 million tax expense for the Transition Tax, which we initially recorded in the quarter ended December 31, 2017, reflecting additional information obtained relating to earnings and profits, foreign tax credits, and state taxes. Additional work is still necessary for a more detailed analysis of our historical foreign earnings. Any subsequent adjustment to these amounts will be recorded to current tax expense in the quarter of 2018 when the analysis is complete. We are subject to additional requirements of the 2017 Tax Act during the year ended December 31, 2018. Those provisions include a tax on global intangible low-taxed income (“GILTI”), a limitation of certain executive compensation, and a deduction for foreign derived intangible income (“FDII”). We have elected to account for GILTI as a period cost, and therefore included GILTI expense in the effective tax rate calculation. Our 2018 effective tax rate includes our estimates of these new provisions, with a net tax benefit of $1 million recorded in Q1. Our estimates may be revised in future periods as we obtain additional data, and as the Internal Revenue Service (“IRS”) issues new guidance implementing the law changes. 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 March 31, 2018, accrued interest was $11 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, and have various ongoing state income tax audits. We are separately under examination by the IRS for the short-period 2011, 2012 and 2013 tax years and under an employment tax audit by the IRS for the 2013 and 2014 tax years. 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 March 31, 2018, no material assessments have resulted, except as noted below regarding our 2009 and 2010 IRS audit with Expedia. In January 2017, as part of the IRS audit of Expedia, we received Notices of Proposed Adjustment from the IRS for the 2009 and 2010 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 $10 million to $14 million after consideration of competent authority relief, exclusive of interest and penalties. 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 and 2010 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 Corporation (“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. At this time, the U.S. Department of the Treasury has not withdrawn the requirement from its regulations to include stock-based compensation in intercompany cost-sharing arrangements. The Company recorded a tax benefit of $1 million in its unaudited condensed consolidated statement of operations for both the three months ended March 31, 2018 and 2017. The Company will continue to monitor this matter and related potential impacts to its consolidated financial statements.

NOTE 8: 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.

Our effective tax rate for the three months ended March 31, 2018 and 2017 was 76.2% and 48.0%, respectively. For the three months ended March 31, 2018, the effective tax rate was greater than the federal statutory rate primarily due to international provisions from the U.S. Tax Cuts and Jobs Act of 2017 (“2017 Tax Act”), discussed below, foreign valuation allowances, and the income tax effects of the accounting for share based compensation. The change in the effective tax rate for the three months ended March 31, 2018 compared to the three months ended March 31, 2017 rate was primarily due to the Transition Tax, discussed below, and a lower stock price resulting in stock compensation shortfalls.

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.

On December 22, 2017, the SEC issued Staff Accounting Bulletin No. 118, or SAB 118, which allows us to record provisional amounts during a measurement period not to extend beyond one year of the enactment date. The measurement period is deemed to have ended earlier when the registrant has obtained, prepared, and analyzed the information necessary to finalize its accounting. During the measurement period, impacts of the law are expected to be recorded at the time a reasonable estimate for all or a portion of the effects can be made, and provisional amounts can be recognized and adjusted as information becomes available, prepared, or analyzed.

During the quarter ended March 31, 2018, we recorded an incremental $5 million tax expense for the Transition Tax, which we initially recorded in the quarter ended December 31, 2017, reflecting additional information obtained relating to earnings and profits, foreign tax credits, and state taxes. Additional work is still necessary for a more detailed analysis of our historical foreign earnings. Any subsequent adjustment to these amounts will be recorded to current tax expense in the quarter of 2018 when the analysis is complete.

We are subject to additional requirements of the 2017 Tax Act during the year ended December 31, 2018. Those provisions include a tax on global intangible low-taxed income (“GILTI”), a limitation of certain executive compensation, and a deduction for foreign derived intangible income (“FDII”). We have elected to account for GILTI as a period cost, and therefore included GILTI expense in the effective tax rate calculation. Our 2018 effective tax rate includes our estimates of these new provisions, with a net tax benefit of $1 million recorded in Q1. Our estimates may be revised in future periods as we obtain additional data, and as the Internal Revenue Service (“IRS”) issues new guidance implementing the law changes.

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 March 31, 2018, accrued interest was $11 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, and have various ongoing state income tax audits. We are separately under examination by the IRS for the short-period 2011, 2012 and 2013 tax years and under an employment tax audit by the IRS for the 2013 and 2014 tax years. 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 March 31, 2018, no material assessments have resulted, except as noted below regarding our 2009 and 2010 IRS audit with Expedia.

In January 2017, as part of the IRS audit of Expedia, we received Notices of Proposed Adjustment from the IRS for the 2009 and 2010 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 $10 million to $14 million after consideration of competent authority relief, exclusive of interest and penalties. 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 and 2010 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 Corporation (“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. At this time, the U.S. Department of the Treasury has not withdrawn the requirement from its regulations to include stock-based compensation in intercompany cost-sharing arrangements. The Company recorded a tax benefit of $1 million in its unaudited condensed consolidated statement of operations for both the three months ended March 31, 2018 and 2017. The Company will continue to monitor this matter and related potential impacts to its consolidated financial statements.