Fair Value (Fair Value of Financial Instruments) (Details) - USD ($) $ in Millions		Dec. 31, 2016	Dec. 31, 2015
Carrying Amount [Member]
Available-for-sale securities		$ 2.8	$ 2.8
Debt maturing within one year	[1]	(18.1)	(55.2)
Long-term debt	[1]	(1,875.8)	(2,150.5)
Foreign exchange forward contracts		(2.4)	0.1
Fair Value [Member]
Available-for-sale securities		2.8	2.8
Debt maturing within one year		(18.1)	(55.2)
Long-term debt		(1,877.5)	(1,622.7)
Foreign exchange forward contracts		$ (2.4)	$ 0.1

[1] (1) The carrying value of debt maturing within one year and long-term debt is presented net of debt issuance costs and includes any related discount or premium and unamortized deferred gains on terminated interest-rate swap agreements, as applicable.