Employee Benefits, Defined Benefit Plans (Details) (USD $) In Millions, except Share data, unless otherwise specified	6 Months Ended		6 Months Ended								6 Months Ended						6 Months Ended					6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012 Additional Capital	Jun. 30, 2011 Additional Capital	Jun. 30, 2012 Common Stock Owned by Union VEBA Subject to Transfer Restriction		Jun. 30, 2011 Common Stock Owned by Union VEBA Subject to Transfer Restriction		Jun. 30, 2012 VEBAs	Jun. 30, 2012 VEBAs Maximum	Jun. 30, 2012 Union VEBA trustrees		Jun. 30, 2011 Union VEBA		Jun. 30, 2012 Union VEBA Company Appointed trustrees	Jun. 30, 2012 Union VEBA USW Appointed trustrees	Jun. 30, 2012 Salaried VEBA	Jun. 30, 2012 Salaried employees Defined benefit plan London, Ontario Facility	Dec. 31, 2011 Salaried employees Defined benefit plan London, Ontario Facility	Dec. 31, 2011 Variable cash contribution VEBAs	Jun. 30, 2012 Variable cash contribution VEBAs Maximum	Jun. 30, 2012 Variable cash contribution VEBAs Annual Cash Flows up to $20 Million	Jun. 30, 2012 Variable cash contribution VEBAs Annual Cash Flows in Excess of $20 Million
Defined Benefit Plan, Actual Plan Asset Allocations
Portion of plan assets invested in equity securities																			55.00%
Portion of plan assets invested in debt securities																			40.00%
Defined Benefit Plan, Assets, Target Allocations
Asset mix target allocation in equity																		55.00%
Asset mix target allocation in debt																		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 on which restriction was lifted											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 on the date the restriction was released for the quarter ended June 30, 2012 and a weighted-average price of $49.58 per share realized by the Union VEBA for the quarter ended June 30, 2011.

[2] At $24.02 per share reorganization value.