Contingencies Hardboard Contingencies Rollforward (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
	Sep. 30, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 Hardboard Siding Reserves [Member]	Dec. 31, 2011 Hardboard Siding Reserves [Member]	Dec. 31, 2010 Hardboard Siding Reserves [Member]	Dec. 31, 2001 Hardboard Siding Reserves [Member]
Loss Contingency Accrual [Roll Forward]
Beginning Balance		$ 21.2			$ 6.2	$ 17.8	$ 24.2
Adjusted to expense (income) during the year	10.7	5.0	11.5	2.5	(5.0)	(10.7)	(2.5)
Claims reimbursement					0	0.6	1.0	19.0
Payments made for claims					(0.4)	(1.1)	(3.6)
Payments made for administrative costs					(0.1)	(0.4)	(1.3)
Ending Balance		$ 14.8	$ 21.2		$ 0.7	$ 6.2	$ 17.8