Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	$ 136.1	$ 163.1	$ 713.6
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax	(12.8)	(9.6)	(0.9)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax	4.5	2.3	3.9
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	0.0	0.0	1.3
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	(30.2)	(9.5)	3.6
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, after Tax	3.5	3.6	3.4
Other Comprehensive Income (Loss), Net of Tax	(35.0)	(13.2)	11.3
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	101.1	149.9	724.9
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	(0.2)	5.2	13.7
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	$ 101.3	$ 144.7	$ 711.2