Non-operating Income (Expense) Disclosure (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Nonoperating Income (Expense) [Abstract]
Interest Expense	$ (19.0)	$ (20.6)	$ (32.9)
Amortization of financing costs and discounts	(0.8)	(0.9)	(1.1)
Capitalized Interest	4.0	2.2	1.9
Interest expense, net of capitalized interest	(15.8)	(19.3)	(32.1)
Investment Income	18.1	9.5	8.0
Gain on securities	(0.4)	0.0	0.0
SERP market adjustments	(0.9)	1.0	0.2
Investment income	17.6	10.5	8.2
Defined Benefit Plan, Other Components of Net Periodic Pension Cost	(4.3)	(9.4)	(6.2)
Foreign currency losses	0.4	(4.4)	2.1
Loss on early debt extinguishment	0.0	0.0	(17.3)
Other Nonoperating Income (Expense)	(3.9)	(13.8)	(21.4)
Total non-operating income (expense)	$ (2.1)	$ (22.6)	$ (45.3)