SIGNIFICANT ACCOUNTING POLICIES	9 Months Ended
SIGNIFICANT ACCOUNTING POLICIES	Sep. 30, 2019
Accounting Policies [Abstract]
SIGNIFICANT ACCOUNTING POLICIES	SIGNIFICANT ACCOUNTING POLICIES Basis of Presentation and Use of Estimates The accompanying unaudited Consolidated Financial Statements have been prepared by the Company in U.S. dollars and in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”) for interim financial reporting, which do not conform in all respects to the requirements of U.S. GAAP for annual financial statements. Accordingly, these notes to the unaudited Consolidated Financial Statements should be read in conjunction with the audited Consolidated Financial Statements prepared in accordance with U.S. GAAP that are contained in the Company’s Annual Report on Form 10-K for the year ended December 31, 2018, filed with the U.S. Securities and Exchange Commission (the “SEC”) and the Canadian Securities Administrators on February 20, 2019. The unaudited Consolidated Financial Statements have been prepared using accounting policies that are consistent with the policies used in preparing the Company’s audited Consolidated Financial Statements for the year ended December 31, 2018, except for the new accounting guidance adopted during the period. The unaudited Consolidated Financial Statements reflect all normal and recurring adjustments necessary for a fair presentation of the Company’s financial position and results of operations for the interim periods. The operating results for the interim periods presented are not necessarily indicative of the results expected for the full year. In preparing the unaudited Consolidated Financial Statements, management is required to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the unaudited Consolidated Financial Statements, and the reported amounts of revenue and expenses during the reporting periods. Actual results could differ from these estimates. On an ongoing basis, management reviews its estimates to ensure that these estimates appropriately reflect changes in the Company’s business and new information as it becomes available. If historical experience and other factors used by management to make these estimates do not reasonably reflect future activity, the Company’s results of operations and financial position could be materially impacted. Principles of Consolidation The unaudited Consolidated Financial Statements include the accounts of the Company and those of its subsidiaries and any variable interest entities for which the Company is the primary beneficiary. All intercompany transactions and balances have been eliminated. Reclassifications Certain reclassifications have been made to prior year amounts to conform to the current year presentation. Adoption of New Accounting Guidance In February 2016, the Financial Accounting Standards Board ("FASB") issued a new standard revising the accounting for leases to increase transparency and comparability among organizations that lease buildings, equipment and other assets by requiring the recognition of lease assets and lease liabilities on the balance sheet. Under the new standard, all leases are classified as either a finance lease or an operating lease. The classification is determined based on whether substantive control has been transferred to the lessee and its determination will govern the pattern of lease cost recognition. Finance leases are accounted for in substantially the same manner as capital leases under the former U.S. GAAP standard. Operating leases are accounted for in the statements of operations and statements of cash flows in a manner substantially consistent with operating leases under the former U.S. GAAP standard. However, as it relates to the balance sheet, operating lessees are, with limited exception, required to record a right-of-use asset and a corresponding lease liability, equal to the present value of the lease payments for each operating lease. Lessees are not required to recognize a right-of-use asset or lease liability for short-term leases, but instead recognizes lease payments as an expense on a straight-line basis over the lease term. The standard also requires lessees and lessors to provide additional qualitative and quantitative disclosures to help financial statement users assess the amounts, timing and uncertainty of cash flows arising from leases. The Company adopted the new standard effective January 1, 2019, using the modified retrospective approach. Upon adoption, the Company elected the available practical expedients, including: (i) the package of practical expedients as defined in the accounting guidance, which among other things, allowed the carry forward of historical lease classifications, (ii) the election to use hindsight in determining the lease terms for all leases, (iii) the transition method, which does not require the restatement of prior periods, (iv) the election to aggregate lease components with non-lease components and account for these payments as a single lease component and (v) the short-term lease exemption, which does not require recognition on the balance sheet for leases with an initial term of 12 months or less. The Company has updated its systems, processes and controls to track, record and account for its lease portfolio, including implementation of a third-party software tool to assist in complying with the new standard. Upon adoption of the new standard, the Company recognized a right-of-use asset and a corresponding lease liability of $302 million. In addition, approximately $20 million of restructuring liabilities associated with facility closures and deferred rents, included in Other non-current liabilities as of December 31, 2018, were reclassified to reduce right-of-use assets. The adoption of the standard did not have a material impact on the Consolidated Statements of Operations, Comprehensive Loss, Equity and Cash Flows for any of the periods presented. See Note 12, "LEASES" for additional details and application of this standard. In August 2018, the FASB issued guidance aligning the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software. The guidance is effective for annual periods beginning after December 15, 2019, and interim periods within those fiscal years with early adoption permitted. The Company has early-adopted this guidance prospectively for all implementation costs incurred after January 1, 2019. Recently Issued Accounting Standards, Not Adopted as of September 30, 2019 In June 2016, the FASB issued guidance on the impairment of financial instruments requiring an impairment model based on expected losses rather than incurred losses. Under this guidance, an entity recognizes as an allowance its estimate of expected credit losses. The guidance is effective for annual periods beginning after December 15, 2019, and interim periods within those annual periods. Early adoption is permitted for annual periods beginning after December 15, 2018, and interim periods within those annual periods. In May 2019, the FASB issued an update allowing a targeted transition relief for the option to irrevocably elect the fair value option for certain financial assets previously measured at amortized cost basis. The Company is evaluating the impact of adoption of this guidance on its financial position, results of operations and cash flows. In August 2018, the FASB issued guidance modifying the disclosure requirements for fair value measurement. The guidance is effective for annual periods beginning after December 15, 2019. The Company is permitted to early-adopt any removed or modified disclosures upon issuance of this update and delay adoption of the additional disclosures until the effective date. The Company is evaluating the impact of adoption of this guidance on its disclosures. In August 2018, the FASB issued guidance modifying the disclosure requirements for employers that sponsor defined benefit pension or other postretirement plans. The guidance is effective for annual periods ending after December 15, 2020, with early adoption permitted. The Company is evaluating the impact of adoption of this guidance on its disclosures.