Goodwill and Intangible Assets (Intangible Assets) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Gross Amount	$ 30.1	$ 28.6
Accumulated Amortization	(21.5)	(21.3)
Net Amount	8.6	7.3
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amount	15.8	15.9
Accumulated Amortization	(15.1)	(14.9)
Net Amount	0.7	1.0
Patents and Others [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amount	14.3	12.7
Accumulated Amortization	(6.4)	(6.4)
Net Amount	$ 7.9	$ 6.3