Comprehensive Income - Schedule of Changes in Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance			$ 696.6	$ 620.4
Other comprehensive loss	$ (23.8)	$ (35.2)	(22.3)	(32.0)
Ending Balance	538.4	662.7	538.4	662.7
Pension and Other Postretirement Benefits Plan Cost
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance			(727.5)	(762.3)
Other comprehensive loss before reclassifications			(69.7)	0.0
Amounts reclassified from accumulated other comprehensive loss	(6.4)	2.2	55.2	6.6
Amounts reclassified due to the disposition of businesses			1.2	3.8
Other comprehensive loss			(13.3)	10.4
Ending Balance	(740.8)	(751.9)	(740.8)	(751.9)
Translation Adjustments
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance			(65.7)	(11.2)
Other comprehensive loss before reclassifications			(8.5)	(54.6)
Amounts reclassified from accumulated other comprehensive loss			0.0	0.0
Amounts reclassified due to the disposition of businesses			(0.7)	13.1
Other comprehensive loss			(9.2)	(41.5)
Ending Balance	(74.9)	(52.7)	(74.9)	(52.7)
AOCI Attributable to Parent
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance			(793.2)	(773.6)
Other comprehensive loss before reclassifications			(78.2)	(54.6)
Amounts reclassified from accumulated other comprehensive loss			55.2	6.7
Amounts reclassified due to the disposition of businesses			0.5	16.9
Other comprehensive loss			(22.5)	(31.0)
Ending Balance	$ (815.7)	(804.6)	$ (815.7)	(804.6)
Changes in the Fair Value of Derivatives
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance				(0.1)
Other comprehensive loss before reclassifications				0.0
Amounts reclassified from accumulated other comprehensive loss				0.1
Amounts reclassified due to the disposition of businesses				0.0
Other comprehensive loss				0.1
Ending Balance		$ 0.0		$ 0.0