Accumulated Other Comprehensive Income (Loss) (Components of Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	$ 419.3	$ 266.4
Impact of ASU 2018-02 adoption	(54.3)
Other comprehensive income (loss) before reclassifications, net of tax expense (benefit)	7.8	11.3
Amounts reclassified from accumulated other comprehensive (loss)	3.7	2.4
Net current period other comprehensive income	11.5	13.7
Balance	403.8	271.2
Foreign Currency Translation Adjustments [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	(47.1)	(71.6)
Other comprehensive income (loss) before reclassifications, net of tax expense (benefit)	5.9	11.1
Net current period other comprehensive income	5.9	11.1
Balance	(41.2)	(60.5)
Derivative Gain (Loss) [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	3.5	3.8
Impact of ASU 2018-02 adoption	0.7
Other comprehensive income (loss) before reclassifications, net of tax expense (benefit)	2.9	0.3
Amounts reclassified from accumulated other comprehensive (loss)	0.9	(0.2)
Net current period other comprehensive income	3.8	0.1
Balance	8.0	3.9
Pension And Postretirement Adjustments [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	(302.3)	(336.0)
Impact of ASU 2018-02 adoption	(55.0)
Other comprehensive income (loss) before reclassifications, net of tax expense (benefit)	(1.0)	(0.1)
Amounts reclassified from accumulated other comprehensive (loss)	2.8	2.6
Net current period other comprehensive income	1.8	2.5
Balance	(355.5)	(333.5)
Accumulated Other Comprehensive (Loss) [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	(345.9)	(403.8)
Balance	$ (388.7)	$ (390.1)