Condensed Consolidated Statements Of Shareholder's Equity (USD $) In Millions	AWI Shareholders [Member] Common Stock [Member]	AWI Shareholders [Member] Capital In Excess Of Par Value [Member]	AWI Shareholders [Member] Retained Earnings (Accumulated Deficit) [Member]	AWI Shareholders [Member] Accumulated Other Comprehensive Income (Loss) [Member]	AWI Shareholders [Member]	Non-Controlling Interest [Member]	Common Stock [Member]	Capital In Excess Of Par Value [Member]	Retained Earnings (Accumulated Deficit) [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Total
Balance at beginning of year at Dec. 31, 2009	$ 0.6	$ 2,052.1	$ 144.4	$ (297.8)		$ 8.6	$ 0.6	$ 2,052.1	$ 144.4	$ (297.8)
Share-based compensation		6.6						6.6
Non-controlling interest purchase		(3.5)		1.1		(8.6)		(3.5)		1.1
Foreign currency translation adjustments				1.5						1.5
Derivative (loss) gain, net				0.2						0.2
Pension and postretirement adjustments				1.3						1.3
Total other comprehensive income				4.1						4.1
Net earnings for period			32.0						32.0		32.0
Comprehensive income					36.1						36.1
Total shareholders' equity					1,938.5						1,938.5
Balance at Sep. 30, 2010	0.6	2,055.2	176.4	(293.7)			0.6	2,055.2	176.4	(293.7)
Balance at beginning of year at Dec. 31, 2010	0.6	1,451.2	(35.3)	(325.7)			0.6	1,451.2	(35.3)	(325.7)
Share-based compensation		13.3						13.3
Foreign currency translation adjustments				2.1						2.1
Derivative (loss) gain, net				(7.1)						(7.1)
Pension and postretirement adjustments				9.3						9.3
Total other comprehensive income				4.3						4.3
Net earnings for period			103.9						103.9		103.9
Comprehensive income					108.2						108.2
Total shareholders' equity					1,212.3						1,212.3
Balance at Sep. 30, 2011	$ 0.6	$ 1,464.5	$ 68.6	$ (321.4)			$ 0.6	$ 1,464.5	$ 68.6	$ (321.4)