Business and Basis of Presentation	6 Months Ended
Jun. 30, 2016
Accounting Policies [Abstract]
Business and Basis of Presentation	NOTE 1. BUSINESS AND BASIS OF PRESENTATION Armstrong World Industries, Inc. (“AWI”) is a Pennsylvania corporation incorporated in 1891. When we refer to "AWI," the "Company," "we," "our" and "us" in these notes, we are referring to AWI and its subsidiaries. On April 1, 2016, we completed our previously announced separation of Armstrong Flooring, Inc. (“AFI”) by allocating the assets and liabilities related primarily to the Resilient Flooring and Wood Flooring segments to AFI and then distributing the common stock of AFI to our shareholders at a ratio of one share of AFI common stock for every two shares of AWI common stock. Subsequent to the separation and distribution, AWI and AFI operate as two independent, publicly-traded companies, with AFI owning and operating the Resilient Flooring and Wood Flooring segments and AWI continuing to own and operate the Building Products (Ceilings) segment. AFI’s historical financial results have been reflected in AWI’s Consolidated Financial Statements as a discontinued operation for all periods presented. Separation costs for the three and six months ended June 30, 2016 were $3.9 million and $31.0 million, respectively. Separation costs for the three and six months ended June 30, 2015 were $5.1 million and $9.4 million, respectively. Separation costs for all periods primarily related to outside professional services and employee compensation and retention and severance accruals which were recorded within the Unallocated Corporate segment in conjunction with this initiative. Beginning in the second quarter of 2016, AFI’s historical financial results for periods prior to April 1, 2016 are reflected in our Condensed Consolidated Financial Statements as a discontinued operation. See Note 3 for additional information. The accounting policies used in preparing the Condensed Consolidated Financial Statements in this Form 10-Q are the same as those used in preparing the Consolidated Financial Statements for the year ended December 31, 2015. These statements should therefore be read in conjunction with the Consolidated Financial Statements and notes that are included in the Form 10-K for the fiscal year ended December 31, 2015. In the opinion of management, all adjustments of a normal recurring nature have been included to provide a fair statement of the results for the reporting periods presented. Operating results for the second quarter and first six months of 2016 and 2015 included in this report are unaudited. Quarterly results are not necessarily indicative of annual earnings, primarily due to the different level of sales in each quarter of the year and the possibility of changes in general economic conditions. These Condensed Consolidated Financial Statements are prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”). The statements include management estimates and judgments, where appropriate. Management utilizes estimates to record many items including certain asset values, allowances for bad debts, inventory obsolescence and lower of cost or market charges, warranty reserves, workers’ compensation, general liability and environmental claims and income taxes. When preparing an estimate, management determines the amount based upon the consideration of relevant information. Management may confer with outside parties, including outside counsel. Actual results may differ from these estimates. Certain amounts in the prior year’s Condensed Consolidated Financial Statements have been recast to conform to the 2016 presentation. Recently Adopted Accounting Standards In June 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2014-12 “Accounting for Share-Based Payments When the Terms of an Award Provide That a Performance Target Could Be Achieved after the Requisite Service Period,” which amends Accounting Standards Codification (“ASC”) Topic 718: Compensation-Stock Compensation. This new guidance requires that a performance target that affects vesting and that could be achieved after the requisite service period be treated as a performance condition and should not be reflected in the estimate of the grant-date fair value of the award. The guidance was effective for annual periods beginning after December 15, 2015. There was no impact on our financial condition, results of operations or cash flows as a result of the adoption of this guidance. In April 2015, the FASB issued ASU 2015-03, “Simplifying the Presentation of Debt Issuance Costs.” This standards update amends existing guidance to require the presentation of debt issuance costs in the balance sheet as a deduction from the carrying amount of the related debt liability instead of a deferred charge. In August 2015, the FASB issued ASU 2015-15, “Presentation and Subsequent Measurement of Debt Issuance Costs Associated with Line-of-Credit Arrangements,” which was issued to address the presentation and subsequent measurement of debt issuance costs related to line-of-credit arrangements. ASU 2015-03 and 2015-15 were effective for annual reporting periods beginning after December 15, 2015. We adopted ASU 2015-03 and 2015-15 retrospectively, resulting in a $4.1 million reduction to other non-current assets and a corresponding decrease to long-term debt as of March 31, 2016. As of December 31, 2015, our adoption of these ASC updates resulted in a $4.7 million reduction to other non-current assets and a corresponding decrease to long-term debt. There was no impact on results of operations as a result of the adoption of this guidance. In April 2015, the FASB issued ASU 2015-05, “Customer's Accounting for Fees Paid in a Cloud Computing Arrangement,” which provides guidance to determine when a customer's fees paid in a cloud computing arrangement include a software license. If a cloud computing arrangement includes a software license, the customer should account for the software license element of the arrangement consistent with the acquisition of other software licenses. If the arrangement does not include a software license, the customer should account for a cloud computing arrangement as a service contract. This new guidance was effective for annual reporting periods beginning after December 15, 2015. There was no impact on our financial condition, results of operations or cash flows as a result of the adoption of this guidance. Recently Issued Accounting Standards In May 2014, the FASB issued ASU 2014-09, “Revenue from Contracts with Customers.” The guidance requires an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to a customer. The ASU will replace most existing revenue recognition guidance in U.S. GAAP when it becomes effective. In August 2015, the FASB issued ASU 2015-14, “Revenue from Contracts with Customers: Deferral of the Effective Date” which defers the effective date for ASU 2014-09 by one year. In March 2016, the FASB issued ASU 2016-08, “Principal versus Agent Considerations (Reporting Gross versus Net),” which clarifies the implementation guidance in ASU 2014-09 relating to principle versus agent considerations. In April 2016, the FASB issued ASU 2016-10, “Identifying Performance Obligations and Licensing” which clarifies the implementation guidance in ASU 2014-09 relating to the identification of performance obligations in a contract, including how entities should account for shipping and handling services it provides after control of goods transfers to a customer. ASU 2016-10 also clarifies guidance on the timing and pattern of revenue recognition for intellectual property licenses. These ASC updates are effective for annual reporting periods beginning after December 15, 2017, but early adoption is permitted. We have not selected a transition method and are currently evaluating the impact these ASC updates would have on our financial condition, results of operations and cash flows. In July 2015, the FASB issued ASU 2015-11, “Simplifying the Measurement of Inventory,” which requires inventory that is measured on a first-in, first-out or average cost basis to be measured at lower of cost and net realizable value, as opposed to the lower of cost or market. For inventory that is measured under the last-in, first-out (“LIFO”) basis or the retail recovery method, there is no change to current measurement requirements. This new guidance must be applied prospectively and is effective for annual reporting periods beginning after December 15, 2016, but early adoption is permitted. We are currently evaluating the impact the adoption of this standard would have on our financial condition, results of operations and cash flows. In November 2015, the FASB issued ASU 2015-17, “Balance Sheet Classification of Deferred Taxes,” which requires entities with a classified balance sheet to present all deferred tax assets and liabilities as non-current. This new guidance is effective for annual reporting periods beginning after December 15, 2016. We are currently evaluating the impact the adoption of this standard would have on our financial condition and cash flows. In January 2016, the FASB issued ASU 2016-01, “Recognition and Measurement of Financial Assets and Financial Liabilities,” which addresses certain aspects of recognition, measurement, presentation, and disclosure of financial instruments. Most notably, this new guidance requires equity investments (except those accounted for under the equity method of accounting or those that result in consolidation of the investee) to be measured at fair value with changes in fair value recognized in net income. This new guidance is effective for annual reporting periods beginning after December 15, 2017. We are currently evaluating the impact the adoption of this standard would have on our financial condition, results of operations and cash flows. In February 2016, the FASB issued ASU 2016-02, “Leases,” which amends accounting for leases, most notably by requiring a lessee to recognize the assets and liabilities that arise from a lease agreement. Specifically, this new guidance will require lessees to recognize a liability to make lease payments and a right-of-use asset representing its right to use the underlying asset for the lease term, with limited exceptions. The accounting applied by a lessor is largely unchanged from that applied under existing U.S. GAAP. This new guidance is effective for annual reporting periods beginning after December 15, 2018 and must be adopted under a modified retrospective basis. We are currently evaluating the impact the adoption of this standard would have on our financial condition, results of operations and cash flows. In March 2016, the FASB issued ASU 2016-05, “Effect of Derivative Contract Novations on Existing Hedge Accounting Relationships,” which amends ASC Topic 815: Derivatives and Hedging. This new guidance clarifies that a novation, or a change in the counterparty to a derivative instrument, by itself would not cause a hedge accounting relationship to be discontinued. This new guidance is effective for annual reporting periods beginning after December 15, 2016 and may be adopted prospectively or retroactively. We are currently evaluating the impact the adoption of this standard would have on our financial condition, results of operations and cash flows. In March 2016, the FASB issued ASU 2016-09, “Improvements to Employee Share-Based Payment Accounting,” which amends ASC Topic 718: Compensation-Stock Compensation. This new guidance simplifies accounting for share-based payments, most notably by requiring all excess tax benefits and tax deficiencies to be recorded as income tax benefits or expense in the income statement and by allowing entities to recognize forfeitures of awards when they occur. This new guidance is effective for annual reporting periods beginning after December 15, 2016 and may be adopted prospectively or retroactively. We are currently evaluating the impact the adoption of this standard would have on our financial condition, results of operations and cash flows.

NOTE 1. BUSINESS AND BASIS OF PRESENTATION

Armstrong World Industries, Inc. (“AWI”) is a Pennsylvania corporation incorporated in 1891. When we refer to "AWI," the "Company," "we," "our" and "us" in these notes, we are referring to AWI and its subsidiaries.

On April 1, 2016, we completed our previously announced separation of Armstrong Flooring, Inc. (“AFI”) by allocating the assets and liabilities related primarily to the Resilient Flooring and Wood Flooring segments to AFI and then distributing the common stock of AFI to our shareholders at a ratio of one share of AFI common stock for every two shares of AWI common stock. Subsequent to the separation and distribution, AWI and AFI operate as two independent, publicly-traded companies, with AFI owning and operating the Resilient Flooring and Wood Flooring segments and AWI continuing to own and operate the Building Products (Ceilings) segment. AFI’s historical financial results have been reflected in AWI’s Consolidated Financial Statements as a discontinued operation for all periods presented. Separation costs for the three and six months ended June 30, 2016 were $3.9 million and $31.0 million, respectively. Separation costs for the three and six months ended June 30, 2015 were $5.1 million and $9.4 million, respectively. Separation costs for all periods primarily related to outside professional services and employee compensation and retention and severance accruals which were recorded within the Unallocated Corporate segment in conjunction with this initiative. Beginning in the second quarter of 2016, AFI’s historical financial results for periods prior to April 1, 2016 are reflected in our Condensed Consolidated Financial Statements as a discontinued operation. See Note 3 for additional information.

The accounting policies used in preparing the Condensed Consolidated Financial Statements in this Form 10-Q are the same as those used in preparing the Consolidated Financial Statements for the year ended December 31, 2015. These statements should therefore be read in conjunction with the Consolidated Financial Statements and notes that are included in the Form 10-K for the fiscal year ended December 31, 2015. In the opinion of management, all adjustments of a normal recurring nature have been included to provide a fair statement of the results for the reporting periods presented. Operating results for the second quarter and first six months of 2016 and 2015 included in this report are unaudited. Quarterly results are not necessarily indicative of annual earnings, primarily due to the different level of sales in each quarter of the year and the possibility of changes in general economic conditions.

These Condensed Consolidated Financial Statements are prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”). The statements include management estimates and judgments, where appropriate. Management utilizes estimates to record many items including certain asset values, allowances for bad debts, inventory obsolescence and lower of cost or market charges, warranty reserves, workers’ compensation, general liability and environmental claims and income taxes. When preparing an estimate, management determines the amount based upon the consideration of relevant information. Management may confer with outside parties, including outside counsel. Actual results may differ from these estimates.

Certain amounts in the prior year’s Condensed Consolidated Financial Statements have been recast to conform to the 2016 presentation.

Recently Adopted Accounting Standards

In June 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2014-12 “Accounting for Share-Based Payments When the Terms of an Award Provide That a Performance Target Could Be Achieved after the Requisite Service Period,” which amends Accounting Standards Codification (“ASC”) Topic 718: Compensation-Stock Compensation. This new guidance requires that a performance target that affects vesting and that could be achieved after the requisite service period be treated as a performance condition and should not be reflected in the estimate of the grant-date fair value of the award. The guidance was effective for annual periods beginning after December 15, 2015. There was no impact on our financial condition, results of operations or cash flows as a result of the adoption of this guidance.

In April 2015, the FASB issued ASU 2015-03, “Simplifying the Presentation of Debt Issuance Costs.” This standards update amends existing guidance to require the presentation of debt issuance costs in the balance sheet as a deduction from the carrying amount of the related debt liability instead of a deferred charge. In August 2015, the FASB issued ASU 2015-15, “Presentation and Subsequent Measurement of Debt Issuance Costs Associated with Line-of-Credit Arrangements,” which was issued to address the presentation and subsequent measurement of debt issuance costs related to line-of-credit arrangements. ASU 2015-03 and 2015-15 were effective for annual reporting periods beginning after December 15, 2015. We adopted ASU 2015-03 and 2015-15 retrospectively, resulting in a $4.1 million reduction to other non-current assets and a corresponding decrease to long-term debt as of March 31, 2016. As of December 31, 2015, our adoption of these ASC updates resulted in a $4.7 million reduction to other non-current assets and a corresponding decrease to long-term debt. There was no impact on results of operations as a result of the adoption of this guidance.

In April 2015, the FASB issued ASU 2015-05, “Customer's Accounting for Fees Paid in a Cloud Computing Arrangement,” which provides guidance to determine when a customer's fees paid in a cloud computing arrangement include a software license. If a cloud computing arrangement includes a software license, the customer should account for the software license element of the arrangement consistent with the acquisition of other software licenses. If the arrangement does not include a software license, the customer should account for a cloud computing arrangement as a service contract. This new guidance was effective for annual reporting periods beginning after December 15, 2015. There was no impact on our financial condition, results of operations or cash flows as a result of the adoption of this guidance.

Recently Issued Accounting Standards

In May 2014, the FASB issued ASU 2014-09, “Revenue from Contracts with Customers.” The guidance requires an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to a customer. The ASU will replace most existing revenue recognition guidance in U.S. GAAP when it becomes effective. In August 2015, the FASB issued ASU 2015-14, “Revenue from Contracts with Customers: Deferral of the Effective Date” which defers the effective date for ASU 2014-09 by one year. In March 2016, the FASB issued ASU 2016-08, “Principal versus Agent Considerations (Reporting Gross versus Net),” which clarifies the implementation guidance in ASU 2014-09 relating to principle versus agent considerations. In April 2016, the FASB issued ASU 2016-10, “Identifying Performance Obligations and Licensing” which clarifies the implementation guidance in ASU 2014-09 relating to the identification of performance obligations in a contract, including how entities should account for shipping and handling services it provides after control of goods transfers to a customer. ASU 2016-10 also clarifies guidance on the timing and pattern of revenue recognition for intellectual property licenses. These ASC updates are effective for annual reporting periods beginning after December 15, 2017, but early adoption is permitted. We have not selected a transition method and are currently evaluating the impact these ASC updates would have on our financial condition, results of operations and cash flows.

In July 2015, the FASB issued ASU 2015-11, “Simplifying the Measurement of Inventory,” which requires inventory that is measured on a first-in, first-out or average cost basis to be measured at lower of cost and net realizable value, as opposed to the lower of cost or market. For inventory that is measured under the last-in, first-out (“LIFO”) basis or the retail recovery method, there is no change to current measurement requirements. This new guidance must be applied prospectively and is effective for annual reporting periods beginning after December 15, 2016, but early adoption is permitted. We are currently evaluating the impact the adoption of this standard would have on our financial condition, results of operations and cash flows.

In November 2015, the FASB issued ASU 2015-17, “Balance Sheet Classification of Deferred Taxes,” which requires entities with a classified balance sheet to present all deferred tax assets and liabilities as non-current. This new guidance is effective for annual reporting periods beginning after December 15, 2016. We are currently evaluating the impact the adoption of this standard would have on our financial condition and cash flows.

In January 2016, the FASB issued ASU 2016-01, “Recognition and Measurement of Financial Assets and Financial Liabilities,” which addresses certain aspects of recognition, measurement, presentation, and disclosure of financial instruments. Most notably, this new guidance requires equity investments (except those accounted for under the equity method of accounting or those that result in consolidation of the investee) to be measured at fair value with changes in fair value recognized in net income. This new guidance is effective for annual reporting periods beginning after December 15, 2017. We are currently evaluating the impact the adoption of this standard would have on our financial condition, results of operations and cash flows.

In February 2016, the FASB issued ASU 2016-02, “Leases,” which amends accounting for leases, most notably by requiring a lessee to recognize the assets and liabilities that arise from a lease agreement. Specifically, this new guidance will require lessees to recognize a liability to make lease payments and a right-of-use asset representing its right to use the underlying asset for the lease term, with limited exceptions. The accounting applied by a lessor is largely unchanged from that applied under existing U.S. GAAP. This new guidance is effective for annual reporting periods beginning after December 15, 2018 and must be adopted under a modified retrospective basis. We are currently evaluating the impact the adoption of this standard would have on our financial condition, results of operations and cash flows.

In March 2016, the FASB issued ASU 2016-05, “Effect of Derivative Contract Novations on Existing Hedge Accounting Relationships,” which amends ASC Topic 815: Derivatives and Hedging. This new guidance clarifies that a novation, or a change in the counterparty to a derivative instrument, by itself would not cause a hedge accounting relationship to be discontinued. This new guidance is effective for annual reporting periods beginning after December 15, 2016 and may be adopted prospectively or retroactively. We are currently evaluating the impact the adoption of this standard would have on our financial condition, results of operations and cash flows.

In March 2016, the FASB issued ASU 2016-09, “Improvements to Employee Share-Based Payment Accounting,” which amends ASC Topic 718: Compensation-Stock Compensation. This new guidance simplifies accounting for share-based payments, most notably by requiring all excess tax benefits and tax deficiencies to be recorded as income tax benefits or expense in the income statement and by allowing entities to recognize forfeitures of awards when they occur. This new guidance is effective for annual reporting periods beginning after December 15, 2016 and may be adopted prospectively or retroactively. We are currently evaluating the impact the adoption of this standard would have on our financial condition, results of operations and cash flows.