Document And Entity Information - shares	6 Months Ended
	Jun. 30, 2015	Jul. 22, 2015
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2015
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q2
Entity Registrant Name	ARMSTRONG WORLD INDUSTRIES INC
Entity Central Index Key	0000007431
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		55,304,261
Trading Symbol	awi