Principles of Consolidation (Reclassification Out of Accumulated Other Comprehensive Loss) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Reclassifications out of Accumulated Comprehensive loss [Line Items]
Non-union pension and postretirement benefits	$ (0.4)	$ 3.2	$ (0.9)	$ 6.5
Change in other operating liabilities			(40.5)	(14.9)
Payments for tax withheld on equity-based compensation			1.6	2.3
Accounting Standards Update 2017-07 [Member]
Reclassifications out of Accumulated Comprehensive loss [Line Items]
Non-union pension and postretirement benefits		3.2		6.5
Salaries, wages and employee benefits		3.2		6.5
Accounting Standards Update 2016-09 [Member]
Reclassifications out of Accumulated Comprehensive loss [Line Items]
Change in other operating liabilities				(2.3)
Payments for tax withheld on equity-based compensation				2.3
AOCI Attributable to Parent [Member]
Reclassifications out of Accumulated Comprehensive loss [Line Items]
Reclassification adjustment from AOCI, after tax	$ 3.7	$ 3.9	$ 7.4	$ 7.8