Employee Benefits Employee Benefits, Defined Benefit Plans Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2015 USD ($) trustrees	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Accrued Annual Veba Contribution	$ 19.6	$ 13.7
Long-term portion of contingent contribution to Union VEBA – Note 6	29.9	0.0
Loss on removal of Union VEBA net assets – Note 6	493.4	0.0	$ 0.0
Canadian pension plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Benefit Obligation	6.1	7.0	6.6
Defined Benefit Plan, Fair Value of Plan Assets	5.7	6.3	6.2
Defined Benefit Plan, Accumulated Benefit Obligation	5.4	6.2
Defined Benefit Plans, Estimated Future Employer Contributions in Next Fiscal Year	$ 0.3
Union VEBA
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Number of Trustees | trustrees	4
Percent allocation of total contribution between VEBAs	85.50%
Accrued Annual Veba Contribution	$ 16.8
Accrued Veba contingent contribution - total	46.7
Defined Benefit Plan, Benefit Obligation	0.0	391.5
Defined Benefit Plan, Fair Value of Plan Assets	0.0	731.6
Loss on settlement of Union VEBA - net of tax	306.9
Income tax benefit on removal of Union VEBA net assets	$ 186.5
Salaried VEBA
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Percent allocation of total contribution between VEBAs	14.50%
Accrued Annual Veba Contribution	$ 2.8
Defined Benefit Plan, Benefit Obligation	77.9	79.4
Defined Benefit Plan, Fair Value of Plan Assets	58.9	62.2
VEBAs
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Cash flow in determining VEBA obligation	20.0
Defined Benefit Plan, Benefit Obligation	77.9	470.9	374.7
Defined Benefit Plan, Fair Value of Plan Assets	58.9	$ 793.8	$ 780.7
Defined Benefit Plan, Future Amortization of Prior Service Cost (Credit)	4.0
Defined Benefit Plan, Amount to be Amortized from Accumulated Other Comprehensive Income (Loss) Next Fiscal Year	4.5
Defined Benefit Plan, Future Amortization of Gain (Loss)	$ 0.5
Fixed Income Securities | London Ontario Facility Member | Canadian pension plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Actual Plan Asset Allocations	37.00%
Defined Benefit Plan, Target Plan Asset Allocations	30.00%
Equity Securities | London Ontario Facility Member | Canadian pension plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Actual Plan Asset Allocations	59.00%
Defined Benefit Plan, Target Plan Asset Allocations	66.00%
Company Appointed [Member] | Union VEBA
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Number of Trustees | trustrees	2
Usw Appointed [Member] | Union VEBA
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Number of Trustees | trustrees	2
Annual Cash Flows up to $20 Million | VEBAs
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Postretirement Medical Plan Contribution Obligation Percentage	10.00%
Annual Cash Flows in Excess of $20 Million | VEBAs
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Postretirement Medical Plan Contribution Obligation Percentage	20.00%
Maximum | VEBAs
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Postretirement Medical Plan Contribution Obligation	$ 20.0
Variable cash contribution | VEBAs
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Annual VEBA contribution paid	$ 13.7