Basis of Presentation Recently adopted accounting pronouncement (Details) - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other Assets, Noncurrent	$ 109.2	$ 101.3
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets		(4.7)
Assets	3,432.4	3,336.9
Long-term debt	745.0	744.6
Liabilities and Equity	$ 3,432.4	3,336.9
Scenario, Previously Reported [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other Assets, Noncurrent		106.0
Assets		3,341.6
Long-term debt		749.3
Liabilities and Equity		$ 3,341.6