Accumulated Other Comprehensive Loss Components (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 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			(27.6)
Amounts reclassified out			1.2
Other comprehensive (loss) income, net of tax	$ (47.9)	$ 27.2	(26.4)	$ 35.0
Balance, ending	(143.7)		(143.7)
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			1.5
Amounts reclassified out			1.4
Other comprehensive (loss) income, net of tax			2.9
Balance, ending	(1.3)		(1.3)
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 (loss) income, net of tax			0.0
Balance, ending	0.5		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			0.5
Amounts reclassified out			(0.2)
Other comprehensive (loss) income, net of tax			0.3
Balance, ending	(38.7)		(38.7)
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			(29.6)
Amounts reclassified out			0.0
Other comprehensive (loss) income, net of tax			(29.6)
Balance, ending	$ (104.2)		$ (104.2)