Significant Accounting Policies Net Periodic Pension Cost and Net Postretirement Benefit Cost (Details) - Accounting Standards Update 2017-07 [Member] $ in Millions	3 Months Ended
	Mar. 31, 2018 USD ($)
Cost of Goods, Total [Member]
Summary Of Significant Accounting Policies [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Increase (Decrease)	$ 6.6
Selling, General and Administrative Expenses [Member]
Summary Of Significant Accounting Policies [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Increase (Decrease)	1.7
Pension and Other Postretirement Income [Member]
Summary Of Significant Accounting Policies [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Increase (Decrease)	$ 8.3