Contingencies Hardboard Contingencies Rollforward (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2001
Loss Contingency Accrual [Roll Forward]
Beginning Balance	$ 32.9
Adjusted to expense (income) during the year	11.5	2.5	(3.3)
Ending Balance	21.2	32.9
Hardboard Siding Reserves [Member]
Loss Contingency Accrual [Roll Forward]
Beginning Balance	17.8	24.2	31.2
Adjusted to expense (income) during the year	(10.7)	(2.5)	3.3
Claims reimbursement	0.6	1.0	4.0	19.0
Payments made for claims	(1.1)	(3.6)	(10.6)
Payments made for administrative costs	(0.4)	(1.3)	(3.7)
Ending Balance	$ 6.2	$ 17.8	$ 24.2