Postretirement Benefits Other Than Pensions (Details) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2018 USD ($) employees	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Income (Loss) from Continuing Operations before Income Taxes	$ 6.1	$ 80.5	$ 45.5	$ 67.0	$ 44.2	$ 68.3	$ 52.1	$ (3.5)	$ 199.1	$ 161.1	$ 3.5
Other Postretirement Benefit Plan, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Number of retired employees covered | employees									700
Number of active employees covered | employees									600
Plan Amendments											$ (11.0)
Effect of one percentage point increase on accumulated postretirement benefit obligation									$ 0.8	$ 0.6
Amounts that will be amortized from AOCI in next Fiscal Year	3.3								3.3
Estimated future employer contributions in next fiscal year	$ 1.7								$ 1.7
Medical Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Health care cost trend rate assumed for next fiscal year	7.50%				7.50%				7.50%	7.50%
Health care cost trend rate assumed for future years									4.80%	4.80%
Prescription Drug Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Health care cost trend rate assumed for next fiscal year	10.00%				10.00%				10.00%	10.00%
Health care cost trend rate assumed for future years									4.80%	4.80%