Accumulated Other Comprehensive Loss Components (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Changes in the Components of Accumulated Other Comprehensive Loss, Net of Tax [Roll Forward]
Balance, beginning	$ (117.3)
Other comprehensive income (loss) before reclassifications	20.6
Amounts reclassified out	0.9
Other comprehensive income, net of tax	21.5	$ 7.8
Balance, ending	(95.8)
Gains (Losses) on Cash Flow Hedges [Member]
Changes in the Components of Accumulated Other Comprehensive Loss, Net of Tax [Roll Forward]
Balance, beginning	(4.2)
Other comprehensive income (loss) before reclassifications	1.2
Amounts reclassified out	1.0
Other comprehensive income, net of tax	2.2
Balance, ending	(2.0)
Unrealized Gains on Investment Securities [Member]
Changes in the Components of Accumulated Other Comprehensive Loss, Net of Tax [Roll Forward]
Balance, beginning	0.5
Other comprehensive income (loss) before reclassifications	0.0
Amounts reclassified out	0.0
Other comprehensive income, net of tax	0.0
Balance, ending	0.5
Defined Benefit Pension and Other Postretirement Plans [Member]
Changes in the Components of Accumulated Other Comprehensive Loss, Net of Tax [Roll Forward]
Balance, beginning	(39.0)
Other comprehensive income (loss) before reclassifications	(0.6)
Amounts reclassified out	(0.1)
Other comprehensive income, net of tax	(0.7)
Balance, ending	(39.7)
Foreign Currency Translation [Member]
Changes in the Components of Accumulated Other Comprehensive Loss, Net of Tax [Roll Forward]
Balance, beginning	(74.6)
Other comprehensive income (loss) before reclassifications	20.0
Amounts reclassified out	0.0
Other comprehensive income, net of tax	20.0
Balance, ending	$ (54.6)