Accumulated Other Comprehensive Income (Loss) (Components of Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	$ 261.2	$ 419.3
Other comprehensive income (loss) before reclassifications, net of tax expense (benefit)	0.4	7.8
Amounts reclassified from accumulated other comprehensive (loss)	2.6	3.7
Net current period other comprehensive income (loss)	3.0	11.5
Balance	280.3	403.8
ASU 2017-12 [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Impact of ASU adoption	0.1
ASU 2018-02 [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Impact of ASU adoption		(54.3)
Foreign Currency Translation Adjustments [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	(74.7)	(47.1)
Other comprehensive income (loss) before reclassifications, net of tax expense (benefit)	5.3	5.9
Net current period other comprehensive income (loss)	5.3	5.9
Balance	(69.4)	(41.2)
Derivative Gain (Loss) [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	5.3	3.5
Other comprehensive income (loss) before reclassifications, net of tax expense (benefit)	(5.6)	2.9
Amounts reclassified from accumulated other comprehensive (loss)	0.5	0.9
Net current period other comprehensive income (loss)	(5.1)	3.8
Balance	0.3	8.0
Derivative Gain (Loss) [Member] | ASU 2017-12 [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Impact of ASU adoption	0.1
Derivative Gain (Loss) [Member] | ASU 2018-02 [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Impact of ASU adoption		0.7
Pension And Postretirement Adjustments [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	(390.2)	(302.3)
Other comprehensive income (loss) before reclassifications, net of tax expense (benefit)	0.7	(1.0)
Amounts reclassified from accumulated other comprehensive (loss)	2.1	2.8
Net current period other comprehensive income (loss)	2.8	1.8
Balance	(387.4)	(355.5)
Pension And Postretirement Adjustments [Member] | ASU 2018-02 [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Impact of ASU adoption		(55.0)
Accumulated Other Comprehensive (Loss) [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	(459.6)	(345.9)
Balance	(456.5)	(388.7)
Accumulated Other Comprehensive (Loss) [Member] | ASU 2017-12 [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Impact of ASU adoption	$ 0.1
Accumulated Other Comprehensive (Loss) [Member] | ASU 2018-02 [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Impact of ASU adoption		$ (54.3)