Accumulated Other Comprehensive (Loss) (Components of Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	$ 266.4	$ 768.8
Other comprehensive income (loss) income before reclassifications, net of tax expense (benefit)	16.6	(15.9)
Amounts reclassified from accumulated other comprehensive (loss)	21.1	27.2
Net current period other comprehensive income (loss)	37.7	11.3
Balance	366.2	259.1
AFI [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Separation of AFI, net of tax (benefit)		56.8
Foreign Currency Translation Adjustments [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	(71.6)	(33.8)
Other comprehensive income (loss) income before reclassifications, net of tax expense (benefit)	20.9	(13.8)
Net current period other comprehensive income (loss)	20.9	(13.8)
Balance	(50.7)	(52.2)
Foreign Currency Translation Adjustments [Member] | AFI [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Separation of AFI, net of tax (benefit)		(4.6)
Derivative Gain (Loss) [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	3.8	(3.3)
Other comprehensive income (loss) income before reclassifications, net of tax expense (benefit)	(1.7)	(4.9)
Amounts reclassified from accumulated other comprehensive (loss)	(0.3)	6.1
Net current period other comprehensive income (loss)	(2.0)	1.2
Balance	1.8	(2.5)
Derivative Gain (Loss) [Member] | AFI [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Separation of AFI, net of tax (benefit)		(0.4)
Pension And Postretirement Adjustments [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	(336.0)	(450.3)
Other comprehensive income (loss) income before reclassifications, net of tax expense (benefit)	(2.6)	2.8
Amounts reclassified from accumulated other comprehensive (loss)	21.4	21.1
Net current period other comprehensive income (loss)	18.8	23.9
Balance	(317.2)	(364.6)
Pension And Postretirement Adjustments [Member] | AFI [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Separation of AFI, net of tax (benefit)		61.8
Accumulated Other Comprehensive (Loss) [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	(403.8)	(487.4)
Balance	$ (366.1)	$ (419.3)