COMMITMENTS AND CONTINGENCIES	9 Months Ended
COMMITMENTS AND CONTINGENCIES	Sep. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES Competition and Consumer Protection Reviews At times, online platforms, including online travel platforms, have been the subject of investigations or inquiries by various national competition authorities ("NCAs") or other governmental authorities regarding competition law matters, consumer protection issues or other areas of concern. The Company is or has been involved in many such investigations. For example, the Company has been and continues to be involved in investigations related to whether Booking.com's contractual parity arrangements with accommodation providers, sometimes also referred to as "most favored nation" or "MFN" provisions, are anti-competitive because they require accommodation providers to provide Booking.com with room rates, conditions or availability that are at least as favorable as those offered to other online travel companies ("OTCs") or through the accommodation provider's website. To resolve and close certain of the investigations, the Company has from time to time made commitments to the investigating authorities regarding future business practices or activities. For example, Booking.com has made commitments to several NCAs, including agreeing to narrow the scope of its parity clauses, in order to resolve parity-related investigations. In addition, in September 2017, the Swiss Price Surveillance Office opened an investigation into the level of commissions of Booking.com in Switzerland and the investigation is ongoing. Some authorities are reviewing the online hotel booking sector more generally through market inquiries and the Company cannot predict the outcome of such inquiries or any resulting impact on its business, results of operations, cash flows or financial condition. NCAs or other governmental authorities are continuing to review the activities of online platforms, including through the use of consumer protection powers. In October 2017, the United Kingdom's NCA (the Competition and Markets Authority, or CMA) launched a consumer protection law investigation into the clarity, accuracy and presentation of information on hotel booking sites with a specific focus on the display of search results (e.g., ranking), claims regarding discounts, methods of "pressure selling" (such as allegedly creating false impressions regarding room availability) and failure to disclose hidden charges. In connection with this investigation, Booking.com, agoda and KAYAK, along with a number of other OTCs, voluntarily agreed to certain commitments with the CMA addressing its concerns in resolution of this investigation, which took effect on September 1, 2019. Among other things, the commitments provided to the CMA include showing prices inclusive of all mandatory taxes and charges, providing information about the effect of money earned on search result rankings on or before the search results page and making certain adjustments to how discounts and statements concerning popularity or availability are shown to consumers. The CMA has stated that it expects all participants in the online travel market to adhere to the same standards, regardless of whether they formally signed the commitments. The commitments conclude the CMA's investigation without finding an infringement or an admission of wrongdoing of the OTCs involved. The Company is unable to predict what, if any, effect the commitments made to the CMA will have on its business, industry practices or online commerce more generally. The Company is unable to predict how any current or future investigations or litigation may be resolved or the long-term impact of any such resolution on its business. For example, competition and consumer-law related investigations, legislation or issues have and could in the future result in private litigation. More immediate results could include, among other things, the imposition of fines, commitments to change certain business practices or reputational damage, any of which could harm the Company's business, results of operations, brands or competitive position. Tax Matters French tax authorities conducted an audit of Booking.com for the years 2003 through 2012. They are asserting that Booking.com has a permanent establishment in France and are seeking to recover what they claim are unpaid income and value-added taxes. In December 2015, the French tax authorities issued Booking.com assessments related to those tax years for approximately 356 million Euros, the majority of which would represent penalties and interest. The Company believes that Booking.com has been, and continues to be, in compliance with French tax law, and the Company is contesting the assessments. The Company has not recorded a liability in connection with these assessments. In December 2018, the French tax authorities issued a formal demand for payment of the amounts assessed. As a result, in January 2019, the Company paid the assessments of approximately 356 million Euros ($403 million) in order to preserve its right to contest the assessments in court. The payment, which is included in "Other assets" in the Consolidated Balance Sheet at September 30, 2019, does not constitute an admission that the Company owes the taxes and will be refunded (with interest) to the Company to the extent the Company prevails. If the Company is unable to resolve the matter with the French tax authorities, the Company plans to challenge the assessments in the French courts. The French tax authorities have begun a similar audit of the tax years 2013 through 2015 and recently extended the audit to include the years 2016 through 2018, both of which could result in additional assessments. Italian authorities are reviewing Booking.com's activities for the years 2011 through 2015. They are reviewing whether Booking.com has a permanent establishment in Italy and Booking.com's transfer pricing policies in Italy. The Company believes that Booking.com has been, and continues to be, in compliance with Italian tax law. The Company is cooperating with the investigation but intends to contest any allegation that Booking.com has a permanent establishment in Italy or that its transfer pricing policies are inappropriate. In December 2018, the Italian tax authorities issued an assessment on the Italian Booking.com subsidiary for approximately 48 million Euros ($52 million) for the 2013 tax year, asserting that its transfer pricing policies were inadequate. The Company has not recorded a liability in connection with this assessment. It is unclear what further actions, if any, the Italian authorities will take. Such actions could include closing the investigation, assessing Booking.com additional taxes, the imposition of interest, fines and penalties and/or bringing criminal charges. In addition, Turkish tax authorities have asserted that Booking.com has a permanent establishment in Turkey and have issued tax assessments for the years 2012 through 2017 for approximately 544 million Turkish Lira ($96 million), including interest and penalties. The Company believes that Booking.com has been, and continues to be, in compliance with Turkish tax law, and the Company is contesting these assessments. The Company has not recorded a liability in connection with these assessments. As a result of an internal review of tax policies and positions at one of the Company's smaller subsidiaries, the Company identified two issues related to the application of certain non-income-based tax laws to that subsidiary's business. In the third and fourth quarters of 2018, the Company accrued related travel transaction taxes totaling approximately $46 million, based on the Company's estimate of the probable travel transaction tax owed for the prior periods, including interest and penalties, as applicable. At September 30, 2019, the Company had $65 million accrued related to these travel transaction taxes. The Company accrued $10 million in the third quarter of 2019. The related expenses are included in "General and administrative" expense in the Unaudited Consolidated Statement of Operations. The Company currently estimates that the reasonably possible loss related to these matters in excess of the amount accrued is approximately $25 million. The Company's internal review is ongoing, and, to the extent the Company determines that the probable taxes owed related to these matters exceed what has already been accrued or new issues are identified during this review, the Company may need to accrue additional amounts, which could adversely affect the Company’s business, results of operations, financial condition and cash flows. During the second quarter 2019, the Company identified the nonpayment in prior periods of a wage-related tax under Netherlands' law on compensation paid to certain highly-compensated former employees in the year of their separation from employment with Booking.com. The Company has informed the Dutch tax authorities of the nonpayment and, to correct this immaterial error, has accrued a liability of $61 million (before tax) based on the Company's estimate of the probable tax owed for prior tax years, including interest (but not including any potential penalties, which cannot reasonably be estimated). This expense is recorded in "Personnel" expenses in the Unaudited Consolidated Statement of Operations for the nine months ended September 30, 2019. In July 2019, France signed into law a 3% digital services tax which is retroactively applicable as of January 1, 2019. The Company accrued a liability of $29 million for this digital services tax for the first nine months of 2019. The expense is included in "General and administrative" expenses in the Unaudited Consolidated Statements of Operations for the three and nine months ended September 30, 2019. From time to time, the Company is involved in other tax-related audits, investigations or proceedings, which could relate to income taxes, value-added taxes, sales taxes, employment taxes, etc. For example, the Company is subject to legal proceedings in the United States related to travel transaction taxes (e.g., hotel occupancy taxes, sales taxes, etc.). Any taxes or other assessments in excess of the Company's current tax provisions, whether in connection with the foregoing or otherwise (including the resolution of any tax proceedings), could have a material adverse effect on the Company's business, effective tax rate, results of operations and financial condition. Turkish Matter From time to time the Company has been subject to legal proceedings and claims regarding whether it is subject to local registration requirements. In March 2017, in connection with a lawsuit begun in 2015 by the Association of Turkish Travel Agencies claiming that Booking.com is required to meet certain registration requirements in Turkey, a Turkish court ordered Booking.com to suspend offering Turkish hotels and accommodations to Turkish residents, which had a negative impact on the Company's growth and results of operations. In October 2019, the Turkish court issued judgment in favor of the Association of Turkish Travel Agencies, finding that Booking.com must meet certain registration requirements in order to offer Turkish hotels and accommodations to Turkish residents. If Booking.com does not successfully appeal this decision or meet the Turkish registration requirements, Booking.com will be unable to resume offering Turkish hotels and accommodations to Turkish residents, which would continue to negatively impact the Company's results of operations. Other Matters The Company accrues for certain legal contingencies where it is probable that a loss has been incurred and the amount can be reasonably estimated. Such accrued amounts are not material to the Company's balance sheets and provisions recorded have not been material to the Company's results of operations or cash flows. From time to time, the Company has been, and expects to continue to be, subject to legal proceedings and claims in the ordinary course of business, including claims of alleged infringement of third-party intellectual property rights. Such claims, even if not meritorious, could result in the expenditure of significant financial and managerial resources, divert management's attention from the Company's business objectives and adversely affect the Company's business, results of operations, financial condition and cash flows. Liability associated with the Earnout Arrangement for Business Acquisition At December 31, 2018, the Company's Consolidated Balance Sheet included a liability of $28 million for contingent consideration related to a business acquisition in 2015. The fair value of the liability, which had been considered a "Level 3" fair value measurement (see Note 6), was based upon probability-weighted average payments for specific performance factors from the acquisition date through the performance period which ended on March 31, 2019. In the second quarter of 2019, the Company paid $37 million to settle this liability. Building Construction In September 2016, the Company signed a turnkey agreement to construct an office building for Booking.com’s headquarters in the Netherlands for 270 million Euros. Upon signing this agreement, the Company paid 43 million Euros for the acquired land-use rights, which was included in “Other assets” in the Consolidated Balance Sheets for periods prior to January 1, 2019. The land-use rights were reclassified from "Other assets" to "Operating lease assets" on January 1, 2019 as part of the adoption of ASC 842, Leases (see Note 1). In addition, since signing the turnkey agreement the Company has made several progress payments principally related to the construction of the building, which are included in "Property and equipment, net" in the Consolidated Balance Sheets. At September 30, 2019, the Company has a remaining obligation of 124 million Euros ($135 million) related to the building construction, which will be paid through 2021, when the Company anticipates construction will be complete. In addition to the turnkey agreement, the Company has a remaining obligation at September 30, 2019 to pay 72 million Euros ($79 million) over the remaining term of the acquired land lease. The Company will also make additional capital expenditures to fit out and furnish the office space. Other Contractual Obligation In 2018, the Company signed an agreement for a lease related to approximately 222,000 square feet of office space in the city of Manchester in the United Kingdom for the headquarters of Rentalcars.com. The Company's obligation to execute the lease is conditional upon the lessor completing certain activities, which are expected to be completed in 2021. If these activities are completed, the lease will commence for a term of approximately 13 years and the Company will have a lease obligation of approximately 65 million British Pounds Sterling ($80 million), excluding lease incentives. The Company will also make capital expenditures to fit out and furnish the office space.