Nature Of Operations And Significant Accounting Policies Recently Adopted Accounting Pronouncements (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other Assets, Noncurrent	$ 95.0	$ 101.3
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets		(4.7)
Assets	3,428.0	3,336.9	$ 3,445.5
Long-term Debt, Excluding Current Maturities	745.3	744.6
Liabilities and Equity	$ 3,428.0	$ 3,336.9