NEW ACCOUNTING PRONOUNCEMENTS	6 Months Ended
Jun. 30, 2017
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
NEW ACCOUNTING PRONOUNCEMENTS	NEW ACCOUNTING PRONOUNCEMENTS On March 10, 2017, the Financial Accounting Standards Board (the "FASB") issued Accounting Standards Update ("ASU") No. 2017-07, Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost. The standard requires employers to present the service cost component of the net periodic benefit cost in the same income statement line item as other employee compensation costs arising from services rendered during the period. The other components of net benefit cost, including amortization of prior service cost/credit, and settlement and curtailment effects, are to be included in nonoperating expenses. This ASU is effective for fiscal years, and interim periods within those years, beginning after December 15, 2017, with early adoption permitted in first fiscal quarters only. The Company does not expect this to have a material impact on Operating income and expects this to have no impact on Net income. The Company will adopt this guidance as of January 1, 2018. On January 26, 2017, the FASB issued ASU No. 2017-04, Simplifying the Test for Goodwill Impairment. The standard simplifies the accounting for goodwill impairment by removing Step 2 of the goodwill impairment test (as defined by the FASB), which requires a hypothetical purchase price allocation (implied fair value of goodwill) to measure impairment loss. This ASU is effective for fiscal years, and interim periods within those years, beginning after December 15, 2019, with early adoption permitted. The Company does not expect this ASU to have a significant impact on its financial statement presentation or results. On February 25, 2016, the FASB issued ASU No. 2016-02, Leases. The standard is effective for fiscal years, and interim periods within those years, beginning after December 15, 2018, with early adoption permitted. The guidance requires lessees to recognize a right-of-use asset and a lease liability on the balance sheet for all leases (with the exception of short-term leases) at the lease commencement date and recognize expenses on the income statement in a similar manner to the current guidance in Accounting Standards Codification 840, Leases. The lease liability will be measured at the present value of the unpaid lease payments and the right-of-use asset will be derived from the calculation of the lease liability. Lease payments will include fixed and in-substance fixed payments, variable payments based on an index or rate, reasonably certain purchase options, termination penalties, fees paid by the lessee to the owners of a special-purpose entity for restructuring the transaction, and probable amounts the lessee will owe under a residual value guarantee. Lease payments will not include variable lease payments other than those that depend on an index or rate, any guarantee by the lessee of the lessor’s debt, or any amount allocated to non-lease components. The Company has formed a project team to evaluate and implement the standard, and currently believes the most significant impact of this ASU on its accounting will be the balance sheet impact of its aircraft operating leases, which will significantly increase assets and liabilities. As of June 30, 2017, the Company had 78 leased aircraft under operating leases. The Company also has operating leases related to terminal operations space and other real estate leases. Although the real estate leases will also have a substantial impact to the balance sheet, the Company does not expect the leases related to terminal operations space to have a significant impact since variable lease payments, other than those based on an index or rate, are excluded from the measurement of the lease liability. The Company also does not expect the adoption of this ASU to impact any of its existing debt covenants. In addition, the standard eliminates the current build-to-suit lease accounting guidance and could result in derecognition of build-to-suit assets and liabilities that remained on the balance sheet after the end of the construction period. The underlying leases for these facilities will be subject to evaluation under the new standard. See Note 7 for further information on the Company’s build-to-suit projects. The Company anticipates utilizing the modified retrospective transition approach to adopt the standard, which requires application of the new guidance for all periods presented with an option to use certain practical expedients. The Company currently plans to adopt the standard as of January 1, 2018, pending successful implementation of a third–party lease accounting software. The Company is continuing to evaluate the new guidance both internally and through its participation in an industry-working group, and plans to provide additional information at a future date. On May 28, 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers. Following the FASB's finalization of a one year deferral of this standard, the ASU is now effective for fiscal years, and interim periods within those years, beginning after December 15, 2017, with early adoption permitted for fiscal years, and interim periods within those years, beginning after December 15, 2016. The Company has formed a project team to evaluate and work to implement the standard, and currently believes the most significant impact of this ASU on its accounting will be the elimination of the incremental cost method for frequent flyer accounting, which will require the Company to re-value its liabilities associated with Customer flight points with a relative fair value approach, resulting in a significant increase in the liabilities. The Company's liabilities associated with these flight points were $62 million at June 30, 2017, and the Company currently estimates that applying a relative fair value would increase the liabilities by approximately 20 to 25 times that value, depending on various assumptions made at the time of measurement. The adoption of the new standard is also expected to result in different income statement classification for certain types of revenues, such as ancillary revenues, which are currently classified as Other revenues. However, based on the Company's full year 2016 results, the estimated impact of this ASU would not have had a material impact on Operating revenues and would not have impacted any of its existing debt covenants. The Company currently anticipates utilizing the full retrospective method of adoption allowed by the standard, in order to provide for comparative results in all periods presented, and plans to adopt the standard as of January 1, 2018. The Company is continuing to evaluate the new guidance both internally and through its participation in an industry working group, and plans to continue to provide relevant and material information prior to adoption. The Company is in the process of completing its analysis of information necessary to restate prior period results, however it does not believe there are any remaining significant implementation topics associated with the anticipated adoption of this ASU that have not yet been addressed.

NEW ACCOUNTING PRONOUNCEMENTS

On March 10, 2017, the Financial Accounting Standards Board (the "FASB") issued Accounting Standards Update ("ASU") No. 2017-07, Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost. The standard requires employers to present the service cost component of the net periodic benefit cost in the same income statement line item as other employee compensation costs arising from services rendered during the period. The other components of net benefit cost, including amortization of prior service cost/credit, and settlement and curtailment effects, are to be included in nonoperating expenses. This ASU is effective for fiscal years, and interim periods within those years, beginning after December 15, 2017, with early adoption permitted in first fiscal quarters only. The Company does not expect this to have a material impact on Operating income and expects this to have no impact on Net income. The Company will adopt this guidance as of January 1, 2018.

On January 26, 2017, the FASB issued ASU No. 2017-04, Simplifying the Test for Goodwill Impairment. The standard simplifies the accounting for goodwill impairment by removing Step 2 of the goodwill impairment test (as defined by the FASB), which requires a hypothetical purchase price allocation (implied fair value of goodwill) to measure impairment loss. This ASU is effective for fiscal years, and interim periods within those years, beginning after December 15, 2019, with early adoption permitted. The Company does not expect this ASU to have a significant impact on its financial statement presentation or results.

On February 25, 2016, the FASB issued ASU No. 2016-02, Leases. The standard is effective for fiscal years, and interim periods within those years, beginning after December 15, 2018, with early adoption permitted. The guidance requires lessees to recognize a right-of-use asset and a lease liability on the balance sheet for all leases (with the exception of short-term leases) at the lease commencement date and recognize expenses on the income statement in a similar manner to the current guidance in Accounting Standards Codification 840, Leases. The lease liability will be measured at the present value of the unpaid lease payments and the right-of-use asset will be derived from the calculation of the lease liability. Lease payments will include fixed and in-substance fixed payments, variable payments based on an index or rate, reasonably certain purchase options, termination penalties, fees paid by the lessee to the owners of a special-purpose entity for restructuring the transaction, and probable amounts the lessee will owe under a residual value guarantee. Lease payments will not include variable lease payments other than those that depend on an index or rate, any guarantee by the lessee of the lessor’s debt, or any amount allocated to non-lease components.

The Company has formed a project team to evaluate and implement the standard, and currently believes the most significant impact of this ASU on its accounting will be the balance sheet impact of its aircraft operating leases, which will significantly increase assets and liabilities. As of June 30, 2017, the Company had 78 leased aircraft under operating leases. The Company also has operating leases related to terminal operations space and other real estate leases. Although the real estate leases will also have a substantial impact to the balance sheet, the Company does not expect the leases related to terminal operations space to have a significant impact since variable lease payments, other than those based on an index or rate, are excluded from the measurement of the lease liability. The Company also does not expect the adoption of this ASU to impact any of its existing debt covenants.

In addition, the standard eliminates the current build-to-suit lease accounting guidance and could result in derecognition of build-to-suit assets and liabilities that remained on the balance sheet after the end of the construction period. The underlying leases for these facilities will be subject to evaluation under the new standard. See Note 7 for further information on the Company’s build-to-suit projects.

The Company anticipates utilizing the modified retrospective transition approach to adopt the standard, which requires application of the new guidance for all periods presented with an option to use certain practical expedients. The Company currently plans to adopt the standard as of January 1, 2018, pending successful implementation of a third–party lease accounting software. The Company is continuing to evaluate the new guidance both internally and through its participation in an industry-working group, and plans to provide additional information at a future date.

On May 28, 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers. Following the FASB's finalization of a one year deferral of this standard, the ASU is now effective for fiscal years, and interim periods within those years, beginning after December 15, 2017, with early adoption permitted for fiscal years, and interim periods within those years, beginning after December 15, 2016. The Company has formed a project team to evaluate and work to implement the standard, and currently believes the most significant impact of this ASU on its accounting will be the elimination of the incremental cost method for frequent flyer accounting, which will require the Company to re-value its liabilities associated with Customer flight points with a relative fair value approach, resulting in a significant increase in the liabilities. The Company's liabilities associated with these flight points were $62 million at June 30, 2017, and the Company currently estimates that applying a relative fair value would increase the liabilities by approximately 20 to 25 times that value, depending on various assumptions made at the time of measurement. The adoption of the new standard is also expected to result in different income statement classification for certain types of revenues, such as ancillary revenues, which are currently classified as Other revenues. However, based on the Company's full year 2016 results, the estimated impact of this ASU would not have had a material impact on Operating revenues and would not have impacted any of its existing debt covenants. The Company currently anticipates utilizing the full retrospective method of adoption allowed by the standard, in order to provide for comparative results in all periods presented, and plans to adopt the standard as of January 1, 2018. The Company is continuing to evaluate the new guidance both internally and through its participation in an industry working group, and plans to continue to provide relevant and material information prior to adoption. The Company is in the process of completing its analysis of information necessary to restate prior period results, however it does not believe there are any remaining significant implementation topics associated with the anticipated adoption of this ASU that have not yet been addressed.