Principles of Consolidation (Reclassification Out of Accumulated Other Comprehensive Loss) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Reclassifications out of Accumulated Comprehensive loss [Line Items]
Non-union pension and postretirement benefits	$ 6.9	$ 3.3	$ 6.0	$ 9.8
Change in other operating liabilities			(32.3)	14.2
Payments for tax withheld on equity-based compensation			2.0	2.4
Accounting Standards Update 2017-07 [Member]
Reclassifications out of Accumulated Comprehensive loss [Line Items]
Non-union pension and postretirement benefits		3.3		9.8
Salaries, wages and employee benefits		3.3		9.8
Accounting Standards Update 2016-09 [Member]
Reclassifications out of Accumulated Comprehensive loss [Line Items]
Change in other operating liabilities				(2.4)
Payments for tax withheld on equity-based compensation				2.4
AOCI Attributable to Parent [Member]
Reclassifications out of Accumulated Comprehensive loss [Line Items]
Reclassification adjustment from AOCI, after tax	$ 3.4	$ (0.9)	$ 10.8	$ 6.9