Basis of Presentation Recently adopted accounting pronouncement (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other Assets, Noncurrent	$ 106.1	$ 101.3
Assets	3,395.0	3,336.9
Long-term debt	744.8	744.6
Liabilities and Equity	$ 3,395.0	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
Adjustments for New Accounting Pronouncement [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other Assets, Noncurrent		(4.7)
Assets		(4.7)
Long-term debt		(4.7)
Liabilities and Equity		$ (4.7)