Business	12 Months Ended
Dec. 31, 2015
Business [Abstract]
Business	NOTE 1. BUSINESS Armstrong World Industries, Inc. (“AWI”) is a Pennsylvania corporation incorporated in 1891. When we refer to "we," "our" and "us" in these notes, we are referring to AWI and its subsidiaries. We use the term “AWI” when we are referring solely to Armstrong World Industries, Inc. On February 23, 2015, we announced that our board of directors unanimously approved a plan to separate our Resilient Flooring and Wood Flooring segments from our Building Products (Ceilings) segment. The separation will be effected by allocating the assets and liabilities related primarily to the Resilient Flooring and Wood Flooring segments to Armstrong Flooring, Inc. (“AFI”) and then distributing the common stock of AFI to AWI’s shareholders. The separation and distribution will result in AWI and AFI becoming 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. Separation costs of $34.3 million for 2015 primarily relate to outside professional services and employee compensation and severance accruals. We expect the effective date of the separation to be near the end of the first quarter of 2016. In October 2006, the Armstrong World Industries, Inc. Asbestos Personal Injury Settlement Trust (“Asbestos PI Trust”) was created to address AWI’s personal injury (including wrongful death) asbestos-related liability and received a distribution of 37,000,000 shares of our common stock. All present and future asbestos-related personal injury claims against AWI, including contribution claims of co-defendants but excluding certain foreign claims against subsidiaries, arising directly or indirectly out of AWI’s pre-filing use of, or other activities involving, asbestos are channeled to the Asbestos PI Trust. From the fourth quarter of 2012 through the fourth quarter of 2014, the Asbestos PI Trust sold 20,448,362 shares of our common stock. In 2015, the Asbestos Trust sold 4,281,884 shares of our common stock. We did not sell any shares and did not receive any proceeds from these transactions. As a result of these transactions, the Asbestos PI Trust currently holds approximately 9% of our outstanding shares.

NOTE 1. BUSINESS

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

On February 23, 2015, we announced that our board of directors unanimously approved a plan to separate our Resilient Flooring and Wood Flooring segments from our Building Products (Ceilings) segment. The separation will be effected by allocating the assets and liabilities related primarily to the Resilient Flooring and Wood Flooring segments to Armstrong Flooring, Inc. (“AFI”) and then distributing the common stock of AFI to AWI’s shareholders. The separation and distribution will result in AWI and AFI becoming 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. Separation costs of $34.3 million for 2015 primarily relate to outside professional services and employee compensation and severance accruals. We expect the effective date of the separation to be near the end of the first quarter of 2016.

In October 2006, the Armstrong World Industries, Inc. Asbestos Personal Injury Settlement Trust (“Asbestos PI Trust”) was created to address AWI’s personal injury (including wrongful death) asbestos-related liability and received a distribution of 37,000,000 shares of our common stock. All present and future asbestos-related personal injury claims against AWI, including contribution claims of co-defendants but excluding certain foreign claims against subsidiaries, arising directly or indirectly out of AWI’s pre-filing use of, or other activities involving, asbestos are channeled to the Asbestos PI Trust.

From the fourth quarter of 2012 through the fourth quarter of 2014, the Asbestos PI Trust sold 20,448,362 shares of our common stock. In 2015, the Asbestos Trust sold 4,281,884 shares of our common stock. We did not sell any shares and did not receive any proceeds from these transactions. As a result of these transactions, the Asbestos PI Trust currently holds approximately 9% of our outstanding shares.