Document And Entity Information	3 Months Ended
	Mar. 31, 2013	Apr. 23, 2013
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2013
Document Fiscal Year Focus	2013
Document Fiscal Period Focus	Q1
Entity Registrant Name	ARMSTRONG WORLD INDUSTRIES INC
Entity Central Index Key	0000007431
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Trading Symbol	awi
Entity Common Stock, Shares Outstanding		59,146,248