RECENT ACCOUNTING PRONOUNCEMENTS	12 Months Ended
Dec. 31, 2017
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
RECENT ACCOUNTING PRONOUNCEMENTS	RECENT ACCOUNTING PRONOUNCEMENTS In February 2018, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2018-02, “Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income” which amends ASC 220 “Income Statement—Reporting Comprehensive Income.” This update allows a reclassification from accumulated other comprehensive income (AOCI) to retained earnings for the stranded tax effects resulting from the 2017 Tax Act during each fiscal year or quarter in which the effect of the lower tax rate is recorded. The update is effective for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years, with earlier application permitted. We are currently evaluating the effect of this update on our consolidated financial statements; however, we expect the provisional deferred gain to be reclassified from AOCI to retained earnings to be approximately $85 million upon adoption. Securities and Exchange Commission (SEC) Staff Accounting Bulletin No. 118, “Income Tax Accounting Implications of the Tax Cuts and Jobs Act” (SAB 118), has provided guidance for companies that have not completed their accounting for the income tax effects of U.S. Tax Cuts and Jobs Act (the 2017 Tax Act) in the period of enactment, allowing for a measurement period of up to one year after the enactment date to finalize the recording of the related tax impacts. We recognized a provisional deferred tax benefit of $437.9 million, which is included as a component of income tax (benefit) provision. At December 31, 2017, we have not completed our accounting for the tax effects of enactment of the 2017 Tax Act as the income tax benefit may require further adjustments in 2018 due to anticipated additional guidance from the U.S. Department of the Treasury, changes in Olin’s assumptions, completion of 2017 tax returns, and further information and interpretations that become available; however, we have made a reasonable estimate of the effects on our existing deferred tax balances and of the one-time transition tax. Additional revisions to our estimates through the measurement period may have a material impact on our consolidated financial statements. In August 2017, the FASB issued ASU 2017-12, “Targeted Improvements to Accounting for Hedge Activities” which amends ASC 815 “Derivatives and Hedging” (ASC 815). This update is intended to more closely align hedge accounting with companies’ risk management strategies, simplify the application of hedge accounting guidance, and increase transparency as to the scope and results of hedge programs. The update is effective for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years, with earlier application permitted. We are currently evaluating the effect of this update on our consolidated financial statements. In March 2017, the FASB issued ASU 2017-07, “Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost” which amends ASC 715. This update requires the presentation of the service cost component of net periodic benefit income (costs) in the same income statement line item as other employee compensation costs arising from services rendered during the period. The update requires the presentation of the other components of the net periodic benefit income (costs) separately from the line item that includes the service cost and outside of any subtotal of operating income. The update is effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. The guidance in this update is applied on a retrospective basis with earlier application permitted. The adoption of ASU 2017-07 will result in a change in our net periodic benefit income (costs) within operating income, which will be offset by a corresponding change in non-operating income (expense) to reflect the impact of presenting the interest cost, expected return on plan assets and amortization of prior service cost and net actuarial loss components of net periodic benefit income (costs) outside of operating income. We have adopted this update on January 1, 2018 using the retrospective method reflecting the aforementioned reclassification on our consolidated statements of operations in the period of adoption. The adoption of this update did not have a material impact on our consolidated balance sheets or our consolidated statements of cash flows. In January 2017, the FASB issued ASU 2017-04, “Simplifying the Test for Goodwill Impairment” which amends ASC 350. This update will simplify the measurement of goodwill impairment by eliminating Step 2 from the goodwill impairment test. This update will require an entity to perform its annual, or interim, goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount and recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value. The update does not modify the option to perform the qualitative assessment for a reporting unit to determine if the quantitative impairment test is necessary. This update is effective for fiscal years beginning after December 15, 2019, and interim periods within those fiscal years. The guidance in this update is applied on a prospective basis with earlier application permitted. We plan to adopt this update on January 1, 2020 and do not expect the update to have a material impact on our consolidated financial statements. In August 2016, the FASB issued ASU 2016-15, “Classification of Certain Cash Receipts and Cash Payments” which amends ASC 230 “Statement of Cash Flows.” This update will make eight targeted changes to how cash receipts and cash payments are presented and classified in the statement of cash flows. The update is effective for fiscal years beginning after December 15, 2017. The update will require adoption on a retrospective basis unless it is impracticable to apply, in which case it would be required to apply the amendments prospectively as of the earliest date practicable. We adopted this update on January 1, 2018. The adoption of this update did not have a material impact on our consolidated financial statements. In March 2016, the FASB issued ASU 2016-09 “Improvements to Employee Share-Based Payment Accounting” which amends ASC 718 “Compensation—Stock Compensation.” This update will simplify the income tax consequences, accounting for forfeitures and classification on the statements of cash flows of share-based payment arrangements. This update is effective for fiscal years beginning after December 15, 2016, and interim periods within those fiscal years, with earlier application permitted. We adopted this update on January 1, 2017, which was applied prospectively; therefore, prior periods have not been retrospectively adjusted. The adoption of this update did not have a material impact on our consolidated financial statements. In February 2016, the FASB issued ASU 2016-02 “Leases,” which supersedes ASC 840 “Leases” and creates a new topic, ASC 842 “Leases.” Subsequent to the issuance of ASU 2016-02, ASC 842 was amended by various updates that amend and clarify the impact and implementation of the aforementioned update. These updates require lessees to recognize a lease liability and a lease asset for all leases, including operating leases, with a term greater than 12 months on its balance sheet. These updates also expand the required quantitative and qualitative disclosures surrounding leases. These updates are effective for fiscal years beginning after December 15, 2018 and interim periods within those fiscal years, with earlier application permitted. These updates will be applied using a modified retrospective transition approach for leases existing at, or entered into after, the beginning of the earliest comparative period presented in the financial statements. We are currently evaluating the effect of these updates on our consolidated financial statements. In July 2015, the FASB issued ASU 2015-11 “Simplifying the Measurement of Inventory,” which amends ASC 330 “Inventory.” This update requires entities to measure inventory at the lower of cost and net realizable value. Net realizable value is the estimated selling prices in the ordinary course of business, less reasonable predictable costs of completion, disposal and transportation. This update simplifies the current guidance under which an entity must measure inventory at the lower of cost or market. This update does not impact inventory measured using LIFO. This update is effective for fiscal years beginning after December 15, 2016. We adopted this update on January 1, 2017, which was applied prospectively; therefore, prior periods have not been retrospectively adjusted. The adoption of this update did not have a material impact on our consolidated financial statements. In May 2014, the FASB issued ASU 2014-09 “Revenue from Contracts with Customers” (ASU 2014-09), which amends ASC 605 “Revenue Recognition” and creates a new topic, ASC 606 “Revenue from Contracts with Customers” (ASC 606). Subsequent to the issuance of ASU 2014-09, ASC 606 was amended by various updates that amend and clarify the impact and implementation of the aforementioned update. These updates provide guidance on how an entity should recognize revenue to depict the transfer of control of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. Upon initial application, the provisions of these updates are required to be applied retrospectively to each prior reporting period presented or retrospectively with the cumulative effect of initially applying this update recognized at the date of initial application. These updates also expand the disclosure requirements surrounding revenue recorded from contracts with customers. These updates are effective for fiscal years, and interim periods within those years, beginning after December 15, 2017. We adopted these updates on January 1, 2018 using the modified retrospective transition method. The cumulative effect of applying the updates will be recorded to retained earnings as of the date of adoption. The most significant impact the updates will have will be on our accounting policies and disclosures on revenue recognition. The adoption of these updates did not have a material impact on our consolidated financial statements. Expanded disclosures regarding revenue recognition will be included within our consolidated financial statements in the period of adoption.

RECENT ACCOUNTING PRONOUNCEMENTS

In February 2018, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2018-02, “Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income” which amends ASC 220 “Income Statement—Reporting Comprehensive Income.” This update allows a reclassification from accumulated other comprehensive income (AOCI) to retained earnings for the stranded tax effects resulting from the 2017 Tax Act during each fiscal year or quarter in which the effect of the lower tax rate is recorded. The update is effective for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years, with earlier application permitted. We are currently evaluating the effect of this update on our consolidated financial statements; however, we expect the provisional deferred gain to be reclassified from AOCI to retained earnings to be approximately $85 million upon adoption.

Securities and Exchange Commission (SEC) Staff Accounting Bulletin No. 118, “Income Tax Accounting Implications of the Tax Cuts and Jobs Act” (SAB 118), has provided guidance for companies that have not completed their accounting for the income tax effects of U.S. Tax Cuts and Jobs Act (the 2017 Tax Act) in the period of enactment, allowing for a measurement period of up to one year after the enactment date to finalize the recording of the related tax impacts. We recognized a provisional deferred tax benefit of $437.9 million, which is included as a component of income tax (benefit) provision. At December 31, 2017, we have not completed our accounting for the tax effects of enactment of the 2017 Tax Act as the income tax benefit may require further adjustments in 2018 due to anticipated additional guidance from the U.S. Department of the Treasury, changes in Olin’s assumptions, completion of 2017 tax returns, and further information and interpretations that become available; however, we have made a reasonable estimate of the effects on our existing deferred tax balances and of the one-time transition tax. Additional revisions to our estimates through the measurement period may have a material impact on our consolidated financial statements.

In August 2017, the FASB issued ASU 2017-12, “Targeted Improvements to Accounting for Hedge Activities” which amends ASC 815 “Derivatives and Hedging” (ASC 815). This update is intended to more closely align hedge accounting with companies’ risk management strategies, simplify the application of hedge accounting guidance, and increase transparency as to the scope and results of hedge programs. The update is effective for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years, with earlier application permitted. We are currently evaluating the effect of this update on our consolidated financial statements.

In March 2017, the FASB issued ASU 2017-07, “Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost” which amends ASC 715. This update requires the presentation of the service cost component of net periodic benefit income (costs) in the same income statement line item as other employee compensation costs arising from services rendered during the period. The update requires the presentation of the other components of the net periodic benefit income (costs) separately from the line item that includes the service cost and outside of any subtotal of operating income. The update is effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. The guidance in this update is applied on a retrospective basis with earlier application permitted. The adoption of ASU 2017-07 will result in a change in our net periodic benefit income (costs) within operating income, which will be offset by a corresponding change in non-operating income (expense) to reflect the impact of presenting the interest cost, expected return on plan assets and amortization of prior service cost and net actuarial loss components of net periodic benefit income (costs) outside of operating income. We have adopted this update on January 1, 2018 using the retrospective method reflecting the aforementioned reclassification on our consolidated statements of operations in the period of adoption. The adoption of this update did not have a material impact on our consolidated balance sheets or our consolidated statements of cash flows.

In January 2017, the FASB issued ASU 2017-04, “Simplifying the Test for Goodwill Impairment” which amends ASC 350. This update will simplify the measurement of goodwill impairment by eliminating Step 2 from the goodwill impairment test. This update will require an entity to perform its annual, or interim, goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount and recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value. The update does not modify the option to perform the qualitative assessment for a reporting unit to determine if the quantitative impairment test is necessary. This update is effective for fiscal years beginning after December 15, 2019, and interim periods within those fiscal years. The guidance in this update is applied on a prospective basis with earlier application permitted. We plan to adopt this update on January 1, 2020 and do not expect the update to have a material impact on our consolidated financial statements.

In August 2016, the FASB issued ASU 2016-15, “Classification of Certain Cash Receipts and Cash Payments” which amends ASC 230 “Statement of Cash Flows.” This update will make eight targeted changes to how cash receipts and cash payments are presented and classified in the statement of cash flows. The update is effective for fiscal years beginning after December 15, 2017. The update will require adoption on a retrospective basis unless it is impracticable to apply, in which case it would be required to apply the amendments prospectively as of the earliest date practicable. We adopted this update on January 1, 2018. The adoption of this update did not have a material impact on our consolidated financial statements.

In March 2016, the FASB issued ASU 2016-09 “Improvements to Employee Share-Based Payment Accounting” which amends ASC 718 “Compensation—Stock Compensation.” This update will simplify the income tax consequences, accounting for forfeitures and classification on the statements of cash flows of share-based payment arrangements. This update is effective for fiscal years beginning after December 15, 2016, and interim periods within those fiscal years, with earlier application permitted. We adopted this update on January 1, 2017, which was applied prospectively; therefore, prior periods have not been retrospectively adjusted. The adoption of this update did not have a material impact on our consolidated financial statements.

In February 2016, the FASB issued ASU 2016-02 “Leases,” which supersedes ASC 840 “Leases” and creates a new topic, ASC 842 “Leases.” Subsequent to the issuance of ASU 2016-02, ASC 842 was amended by various updates that amend and clarify the impact and implementation of the aforementioned update. These updates require lessees to recognize a lease liability and a lease asset for all leases, including operating leases, with a term greater than 12 months on its balance sheet. These updates also expand the required quantitative and qualitative disclosures surrounding leases. These updates are effective for fiscal years beginning after December 15, 2018 and interim periods within those fiscal years, with earlier application permitted. These updates will be applied using a modified retrospective transition approach for leases existing at, or entered into after, the beginning of the earliest comparative period presented in the financial statements. We are currently evaluating the effect of these updates on our consolidated financial statements.

In July 2015, the FASB issued ASU 2015-11 “Simplifying the Measurement of Inventory,” which amends ASC 330 “Inventory.” This update requires entities to measure inventory at the lower of cost and net realizable value. Net realizable value is the estimated selling prices in the ordinary course of business, less reasonable predictable costs of completion, disposal and transportation. This update simplifies the current guidance under which an entity must measure inventory at the lower of cost or market. This update does not impact inventory measured using LIFO. This update is effective for fiscal years beginning after December 15, 2016. We adopted this update on January 1, 2017, which was applied prospectively; therefore, prior periods have not been retrospectively adjusted. The adoption of this update did not have a material impact on our consolidated financial statements.

In May 2014, the FASB issued ASU 2014-09 “Revenue from Contracts with Customers” (ASU 2014-09), which amends ASC 605 “Revenue Recognition” and creates a new topic, ASC 606 “Revenue from Contracts with Customers” (ASC 606). Subsequent to the issuance of ASU 2014-09, ASC 606 was amended by various updates that amend and clarify the impact and implementation of the aforementioned update. These updates provide guidance on how an entity should recognize revenue to depict the transfer of control of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. Upon initial application, the provisions of these updates are required to be applied retrospectively to each prior reporting period presented or retrospectively with the cumulative effect of initially applying this update recognized at the date of initial application. These updates also expand the disclosure requirements surrounding revenue recorded from contracts with customers. These updates are effective for fiscal years, and interim periods within those years, beginning after December 15, 2017. We adopted these updates on January 1, 2018 using the modified retrospective transition method. The cumulative effect of applying the updates will be recorded to retained earnings as of the date of adoption. The most significant impact the updates will have will be on our accounting policies and disclosures on revenue recognition. The adoption of these updates did not have a material impact on our consolidated financial statements. Expanded disclosures regarding revenue recognition will be included within our consolidated financial statements in the period of adoption.