Employee Benefits, Defined Benefit Plans (Details) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Postretirement Medical Obligations
Accrued annual VEBA contribution	$ 20.0		$ 0
Common stock held by Union VEBA which ceased to be subject to transfer restrictions	2,202,495		1,321,485		1,321,485
Reduction in Common stock owned by Union VEBA	(67.3)		(40.5)		(32.5)
Increase in Additional paid in capital	(67.3)		(40.5)		(32.5)
Weighted average price per share sold by Union VEBA	$ 49.31		$ 49.58		$ 39.39
Reorganization value per share	$ 24.02		$ 24.02		$ 24.02
Benefit Obligations and Funded Status Additional Disclosure
Actuarial loss resulting from a change in benefit cost for plan participants			31.4
Actuarial loss resulting from a decrease in discount rates used to determine benefit obligations	9.7		53.5
Actuarial loss resulting from change in actuarial assumptions			11.9
Net asset In respect of VEBAs	365.9		144.7
Net liability in respect of VEBA	5.3		20.6
Estimated future benefit payments
Expected future benefit payments, 2013	23.1
Expected future benefit payments, 2014	23.4
Expected future benefit payments, 2015	23.5
Expected future benefit payments, 2016	23.5
Expected future benefit payments, 2017	23.5
Expected future benefit payments, 2018-2022	115.0
Components of Net Periodic Benefit Cost (Income)
Net periodic benefit costs (income)	(11.5)		(5.7)		5.1
Additional Paid in Capital
Postretirement Medical Obligations
Reduction in Common stock owned by Union VEBA	(14.4)		(8.8)		(0.7)
Increase in Additional paid in capital	(14.4)		(8.8)		(0.7)
Decrease in Deferred tax assets	(41.3)		(25.0)		(19.6)
Common Stock Owned by Union VEBA
Postretirement Medical Obligations
Reduction in Common stock owned by Union VEBA	(52.9)	[1]	(31.7)	[1]	(31.8)	[1]
Increase in Additional paid in capital	(52.9)	[1]	(31.7)	[1]	(31.8)	[1]
Canadian pension plan
Assumptions used to determine benefit obligations
Discount rate	4.40%		5.60%
Rate of compensation increase	3.00%		3.00%
Assumptions used to determine net periodic benefit cost (income)
Discount rate	5.60%		5.70%		6.70%
Expected long-term return on plan assets	4.60%		5.40%		5.40%
Rate of compensation increase	3.00%		3.50%		3.50%
Change in Benefit Obligation:
Obligation at beginning of year	5.4		5.4
Foreign currency translation adjustment	0.2		(0.1)
Service cost	0.2		0.2		0.1
Interest cost	0.3		0.3		0.3
Actuarial (gain) loss	1.1		(0.2)
Plan participant contributions	0.1		0
Benefits paid by Company	(0.3)		(0.2)
Obligation at end of year	7.0		5.4		5.4
Change in Plan Assets:
FMV of plan assets at beginning of year	4.9		4.9
Foreign currency translation adjustment	0.2		(0.1)
Actual return on assets	0.3		(0.2)
Plan participant contributions	0.1		0
Employer/Company contributions	0.5		0.5
Benefits paid by Company	(0.3)		(0.2)
FMV of plan assets at end of year	5.7		4.9		4.9
Net Funded Status	(1.3)		(0.5)
Net Funded Status
Accumulated plan benefit obligation	6.2		4.9
Plan assets	5.7		4.9		4.9
Net Funded Status	(1.3)		(0.5)
Net benefits expected to be contributed in 2013	0.4
Estimated future benefit payments
Expected future benefit payments, 2013	0.2
Expected future benefit payments, 2014	0.3
Expected future benefit payments, 2015	0.3
Expected future benefit payments, 2016	0.3
Expected future benefit payments, 2017	0.3
Expected future benefit payments, 2018-2022	2.0
Accumulated other comprehensive (loss) income
Accumulated net actuarial (losses) gains	(2.8)		(2.0)
Transition assets	0.3		0.4
Loss recognized in Accumulated other comprehensive income (loss)	(2.5)		(1.6)
Amounts in Accumulated other comprehensive (loss) income expected to be recognized in 2013
Amounts in Accumulated other comprehensive (loss) income expected to be recognized in 2013	0.1
Components of Net Periodic Benefit Cost (Income)
Service cost	0.2		0.2		0.1
Interest cost	0.3		0.3		0.3
Expected return on plan assets	(0.2)		(0.3)		(0.2)
Amortization of prior service cost	0		0		0
Amortization of net loss	0.1		0.1		0
Net periodic benefit costs (income)	0.4		0.3		0.2
Canadian pension plan | London, Ontario Facility | Equity Securities
Defined Benefit Plan at the London, Ontario Facility, Information About Plan Assets
Actual plan asset allocations	62.00%
Asset mix target allocation on long-term investments	61.00%
Canadian pension plan | London, Ontario Facility | Debt Securities
Defined Benefit Plan at the London, Ontario Facility, Information About Plan Assets
Actual plan asset allocations	34.00%
Asset mix target allocation on long-term investments	36.00%
VEBAs
Postretirement Medical Obligations
Cash flow in determining VEBA obligation	20.0
Liquidity requirement	50.0
Change in Benefit Obligation:
Obligation at beginning of year	446.9		348.6
Foreign currency translation adjustment	0		0
Service cost	3.4		2.2		2.0
Interest cost	17.9		17.4		19.1
Actuarial (gain) loss	(66.2)	[2]	96.8	[2]
Plan participant contributions	0		0
Benefits paid by VEBA	(20.8)		(21.1)
Reimbursement from Retiree Drug Subsidy	2.9	[3]	3.0	[3]
Obligation at end of year	384.1		446.9		348.6
Change in Plan Assets:
FMV of plan assets at beginning of year	571.0		506.6
Foreign currency translation adjustment	0		0
Actual return on assets	63.0		16.9
Plan participant contributions	0		0
Employer/Company contributions	20.0		0.1
Benefits paid by VEBA	(20.8)		(21.1)
Reimbursement from Retiree Drug Subsidy	2.9	[3]	3.0	[3]
FMV of plan assets at end of year	744.7		571.0		506.6
Net Funded Status	360.6	[4]	124.1	[4]
Benefit Obligations and Funded Status Additional Disclosure
Actuarial gain due to changes in census data	16.2
Net Funded Status
Accumulated plan benefit obligation	384.1		446.9
Plan assets	744.7		571.0		506.6
Net Funded Status	360.6	[4]	124.1	[4]
Estimated future benefit payments
Expected future benefit payments, 2013	26.0	[5]
Expected future benefit payments, 2014	26.3	[5]
Expected future benefit payments, 2015	26.5	[5]
Expected future benefit payments, 2016	26.6	[5]
Expected future benefit payments, 2017	26.7	[5]
Expected future benefit payments, 2018-2022	131.5	[5]
Accumulated other comprehensive (loss) income
Accumulated net actuarial (losses) gains	(3.2)		(95.1)
Prior service cost	36.9		41.1
Loss recognized in Accumulated other comprehensive income (loss)	(40.1)		(136.2)
Amounts in Accumulated other comprehensive (loss) income expected to be recognized in 2013
Amounts in Accumulated other comprehensive (loss) income expected to be recognized in 2013	5.5
Components of Net Periodic Benefit Cost (Income)
Service cost	3.4		2.2		2.0
Interest cost	17.9		17.4		19.1
Expected return on plan assets	(40.4)		(30.4)		(20.9)
Amortization of prior service cost	4.2	[6]	4.2	[6]	4.2	[6]
Amortization of net loss	3.0		0.6		0.7
Net periodic benefit costs (income)	(11.9)		(6.0)		5.1
VEBAs | Amortization of Prior Service Cost
Amounts in Accumulated other comprehensive (loss) income expected to be recognized in 2013
Amounts in Accumulated other comprehensive (loss) income expected to be recognized in 2013	4.2
VEBAs | Amortization of Net Actuarial Loss
Amounts in Accumulated other comprehensive (loss) income expected to be recognized in 2013
Amounts in Accumulated other comprehensive (loss) income expected to be recognized in 2013	1.3
VEBAs | Maximum
Postretirement Medical Obligations
Administrative expense obligation	0.3		0.3		0.3
Variable cash contribution obligation to VEBAs	20.0
VEBAs | Annual Cash Flows up to $20 Million
Postretirement Medical Obligations
Postretirement medical plan contribution obligation percentage	10.00%
VEBAs | Annual Cash Flows in Excess of $20 Million
Postretirement Medical Obligations
Postretirement medical plan contribution obligation percentage	20.00%
Union VEBA
Postretirement Medical Obligations
Number of trustees	4
Percent allocation of total contribution between VEBAs	85.50%
Accrued annual VEBA contribution	17.1
Increase in Union VEBA assets	108.6	[7]	65.5	[7]	52.1	[7]
Assumptions used to determine benefit obligations
Discount rate	4.00%		4.20%
Initial medical trend rate	8.00%	[8]	8.50%	[8]
Ultimate medical trend rate	5.00%	[8],[9]	5.00%	[8],[9]	5.00%	[9]
Year that rate reaches ultimate trend rate	2019		2019		2019
Effect of one-percentage-point increase in medical trend rate on accumulated postretirement benefit obligation	41.1		50.5
Effect of one-percentage-point decrease in medical trend rate on accumulated postretirement benefit obligation	33.4		40.8
Assumptions used to determine net periodic benefit cost (income)
Discount rate	4.20%		5.25%		5.80%
Expected long-term return on plan assets	7.25%	[10]	6.00%	[10]	4.75%	[10]
Initial medical trend rate used in calculating net periodic benefit cost	8.50%	[9]	9.00%	[9]	9.50%	[9]
Ultimate medical trend rate	5.00%	[8],[9]	5.00%	[8],[9]	5.00%	[9]
Year that rate reaches ultimate trend rate	2019		2019		2019
Effect of one-percentage-point increase on service and interest cost components	2.5		2.7		2.7
Effect of one-percentage-point decrease on service and interest cost components	2.0		2.1		2.2
Change in Plan Assets:
FMV of plan assets at beginning of year	514.7
Sale of Company's common stock by Union VEBA	108.6	[7]	65.5	[7]	52.1	[7]
FMV of plan assets at end of year	685.3		514.7
Net Funded Status	365.9		144.7
Benefit Obligations and Funded Status Additional Disclosure
Actuarial gain due to changes in prescription drug claim costs and Retiree Drug Subsidy assumptions	42.2
Actuarial gain due to a change in participant marital status assumption	9.6
Prescription drug benefit retiree drug subsidy percentage	28.00%
Net Funded Status
Accumulated plan benefit obligation	319.4		370.0
Plan assets	685.3		514.7
Net Funded Status	365.9		144.7
Anticipated Retiree Drug Subsidy
Anticipated Retiree Drug Subsidy, 2013	(3.1)	[5]
Anticipated Retiree Drug Subsidy, 2014	(3.2)	[5]
Anticipated Retiree Drug Subsidy, 2015	(3.3)	[5]
Anticipated Retiree Drug Subsidy, 2016	(3.4)	[5]
Anticipated Retiree Drug Subsidy, 2017	(3.5)	[5]
Anticipated Retiree Drug Subsidy, 2018-2022	(18.5)	[5]
Union VEBA | Company Appointed
Postretirement Medical Obligations
Number of trustees	2
Union VEBA | USW Appointed
Postretirement Medical Obligations
Number of trustees	2
Salaried VEBA
Postretirement Medical Obligations
Percent allocation of total contribution between VEBAs	14.50%
Accrued annual VEBA contribution	2.9
Assumptions used to determine benefit obligations
Discount rate	3.40%		3.75%
Assumptions used to determine net periodic benefit cost (income)
Discount rate	3.75%		4.70%		5.40%
Expected long-term return on plan assets	7.25%	[10]	7.25%	[10]	7.25%	[10]
Change in Plan Assets:
FMV of plan assets at beginning of year	56.3
FMV of plan assets at end of year	59.4		56.3
Net Funded Status	(5.3)		(20.6)
Benefit Obligations and Funded Status Additional Disclosure
Actuarial gain due to change in assumption for annual benefit utilization	11.0
Net Funded Status
Accumulated plan benefit obligation	64.7		76.9
Plan assets	59.4		56.3
Net Funded Status	$ (5.3)		$ (20.6)

[1] At $24.02 per share reorganization value.

[2] The actuarial gain relating to the VEBA plans in 2012 was primarily comprised of (i) a gain of $42.2 due to lower actual prescription drug claim cost and a change in Retiree Drug Subsidy assumption in 2012 in the Union VEBA, (ii) a gain of $16.2 due to changes in census data for both VEBA plans, (iii) a gain of $9.6 relating to a change in the participant marital status assumption in the Union VEBA and (iv) a gain of $11.0 relating to a change in the assumption for annual benefit utilization per participant in the Salaried VEBA, partially offset by a loss of $9.7 due to decrease in discount rates used to determine benefit obligations for both VEBA plans. The actuarial loss relating to the VEBA plans in 2011 was comprised of (i) a loss of $31.4 resulting from an increase in benefit cost for plan participants, (ii) a loss of $53.5 resulting from a decrease in discount rates used to determine benefit obligations for both VEBA plans and (iii) a loss of $11.9 resulting from change in actuarial assumptions.

[3] In January 2005, the Department of Health and Human Services’ Centers for Medicare and Medicaid Services (CMS) released final regulations governing the Medicare prescription drug benefit and other key elements of the Medicare Modernization Act that went into effect January 1, 2006. The Union VEBA is eligible for the Retiree Drug Subsidy because the plan meets the definition of actuarial equivalence and therefore qualifies for federal subsidies equal to 28% of allowable drug costs. As a result, the Company has measured the Union VEBA’s obligations and costs to take into account this subsidy.

[4] With respect to the Prepaid benefit of $360.6 relating to the VEBAs at December 31, 2012, $365.9 was included in Net asset in respect of VEBA and $5.3 was included in Net liability in respect of VEBA on the Consolidated Balance Sheet. With respect to the Prepaid benefit of $124.1 relating to the VEBAs at December 31, 2011, $144.7 was included in Net asset in respect of VEBA and $20.6 was included in Net liability in respect of VEBA on the Consolidated Balance Sheets.

[5] Such amounts were obtained from the VEBAs. The Company's only financial obligations to the VEBAs are to pay the variable contributions, which may not exceed $20.0 annually, and certain administrative fees.

[6] The Company amortizes prior service cost on a straight-line basis over the average remaining years of service to full eligibility for benefits of the active plan participants.

[7] At a weighted-average price of $49.31, $49.58 and $39.39 per share realized by the Union VEBA for the years 2012, 2011 and 2010, respectively.

[8] The medical trend rate assumptions used for the Union VEBA were provided by the Union VEBA and certain industry data were provided by the Company's actuaries. The trend rate is assumed to decline to 5% by 2019 at December 31, 2012 and December 31, 2011. A one-percentage-point increase in the assumed medical trend rates would increase the accumulated postretirement benefit obligation of the Union VEBA by $41.1 and $50.5 at December 31, 2012 and December 31, 2011, respectively. A one-percentage-point decrease in the assumed medical trend rates would decrease the accumulated postretirement benefit obligation of the Union VEBA by $33.4 and $40.8 at December 31, 2012 and December 31, 2011, respectively.

[9] The medical trend rate assumptions used for the Union VEBA, which is currently paying certain prescription drug benefits, were provided by the Union VEBA and certain industry data were provided by the Company's actuaries. The trend rate is assumed to decline to 5% by 2019, 5% by 2019 and 5% by 2019 for 2012, 2011 and 2010, respectively. A one-percentage-point increase in the assumed medical trend rates would increase the aggregate of the service and interest cost components of net periodic benefit costs by $2.5, $2.7 and $2.7 for 2012, 2011 and 2010, respectively. A one-percentage-point decrease in the assumed medical trend rates would decrease the aggregate of the service and interest cost components of net periodic benefit costs by $2.0, $2.1, and $2.2 for 2012, 2011 and 2010, respectively.

[10] The expected long-term rate of return assumption is based on the historical investment portfolios provided to the Company by the VEBAs’ trustees.