Employee Benefits, Defined Benefit Plans (Details) (USD $) In Millions, except Share data, unless otherwise specified	9 Months Ended		9 Months Ended								9 Months Ended						9 Months Ended			9 Months Ended				9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012 Additional Paid in Capital	Sep. 30, 2011 Additional Paid in Capital	Sep. 30, 2012 Common Stock Owned by Union VEBA		Sep. 30, 2011 Common Stock Owned by Union VEBA		Sep. 30, 2012 VEBAs	Sep. 30, 2012 VEBAs Maximum	Sep. 30, 2012 Union VEBA trustrees		Sep. 30, 2011 Union VEBA		Sep. 30, 2012 Union VEBA Company Appointed trustrees	Sep. 30, 2012 Union VEBA USW Appointed trustrees	Sep. 30, 2012 Salaried VEBA	Sep. 30, 2012 Salaried employees Defined benefit plan London, Ontario Facility Equity Securities	Dec. 31, 2011 Salaried employees Defined benefit plan London, Ontario Facility Equity Securities	Sep. 30, 2012 Salaried employees Defined benefit plan London, Ontario Facility Debt Securities	Dec. 31, 2011 Salaried employees Defined benefit plan London, Ontario Facility Debt Securities	Dec. 31, 2011 Variable cash contribution VEBAs	Sep. 30, 2012 Variable cash contribution VEBAs Maximum	Sep. 30, 2012 Variable cash contribution VEBAs Annual Cash Flows up to $20 Million	Sep. 30, 2012 Variable cash contribution VEBAs Annual Cash Flows in Excess of $20 Million
Defined Benefit Plan at the London, Ontario Facility, Information About Plan Assets
Actual plan asset allocations																			55.00%		40.00%
Asset mix target allocation on long-term investments																		55.00%		43.00%
Postretirement Medical Obligations
Number of trustees											4				2	2
Administrative expenses of the VEBAs obligation										$ 0.3
Postretirement medical plan contribution obligation percentage																								10.00%	20.00%
Cash flow in determining VEBA obligation									20.0
Variable cash contribution obligation to VEBAs																							20.0
Liquidity requirement									50.0
Percent allocation of total contribution between VEBAs											85.50%						14.50%
Accrued annual VEBA contribution																						0
Common stock held by Union VEBA which ceased to be subject to transfer restrictions											2,202,495		1,321,485
Increase in Union VEBA assets											108.6	[1]	65.5	[1]
Reduction in Common stock owned by Union VEBA	(67.0)		(14.1)	(9.1)	(52.9)	[2]	(31.7)	[2]
Increase in Additional paid in capital	(67.0)		(14.1)	(9.1)	(52.9)	[2]	(31.7)	[2]
Decrease in Deferred tax assets			$ (41.6)	$ (24.7)
Weighted average price per share sold by Union VEBA											$ 49.31		$ 49.58
Reorganization value per share	$ 24.02	$ 24.02

[1] At a weighted-average price of $49.31 per share for the nine months ended September 30, 2012 and a weighted-average price of $49.58 per share realized by the Union VEBA for the nine months ended September 30, 2011.

[2] At $24.02 per share reorganization value.