Principles of Consolidation (Reclassification Out of Accumulated Other Comprehensive Loss) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Reclassifications out of Accumulated Comprehensive loss [Line Items]
Non-union pension and postretirement benefits	$ (0.5)	$ 3.3
Change in other operating liabilities	(33.1)	(15.9)
Payments for tax withheld on equity-based compensation	1.4	2.3
Accounting Standards Update 2017-07 [Member]
Reclassifications out of Accumulated Comprehensive loss [Line Items]
Non-union pension and postretirement benefits		3.3
Salaries, wages and employee benefits		3.3
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