Income Taxes Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Total current deferred tax assets	$ 0.0	$ 40.2
Deferred Tax Assets, Net, Current	0.0	40.1
Deferred income taxes	373.6	368.8
Deferred Tax Assets, Net, Noncurrent	366.8	359.7
Deferred Tax Assets, Current [Member]
Employee benefits	0.0	26.0
Inventory	0.0	7.5
Prepaid taxes and other	0.0	16.9
Valuation allowance	0.0	(10.2)
Total current deferred tax assets	0.0	40.2
Deferred Tax Liabilities, Current [Member]
Unrealized foreign exchange gain and other	0.0	(0.1)
Deferred Tax Assets, Noncurrent [Member]
Employee benefits	211.1	193.9
Inventory	9.4	0.0
Deferred Tax Assets, Operating Loss Carryforwards	117.0	104.7
Deferred Tax Assets, Tax Credit Carryforwards	25.8	69.8
Deferred Tax Assets, Tax Credit Carryforwards, Other	13.6	14.4
Deferred Tax Assets, Fixed Assets	13.5	6.6
Deferred Tax Assets, Deferred Income	15.0	12.6
Deferred Tax Assets, Noncurrent, Capitalized Expenditures	120.5	111.2
Prepaid taxes and other	22.4	2.3
Deferred Tax Assets, Valuation Allowance, Noncurrent	167.3	146.7
Deferred income taxes	381.0	368.8
Deferred Tax Liabilities, Noncurrent [Member]
Deferred Tax Liabilities, Property, Plant and Equipment	(14.2)	(9.1)
Foreign [Member]
Deferred Tax Assets, Net, Current	0.0	13.1
Deferred Tax Assets, Net, Noncurrent	12.1	(2.5)
Domestic [Member]
Deferred Tax Assets, Net, Current	0.0	27.0
Deferred Tax Assets, Net, Noncurrent	$ 354.7	$ 362.2