Comprehensive Income - Schedule of Changes in Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance			$ 696.6	$ 620.4
Other comprehensive (loss) income	$ (15.8)	$ 23.6	1.5	3.2
Ending Balance	619.5	737.6	619.5	737.6
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			(56.7)	0.0
Amounts reclassified from accumulated other comprehensive loss	63.4	2.2	61.6	4.4
Amounts reclassified due to the disposition of businesses			1.2	3.8
Other comprehensive (loss) income			6.1	8.2
Ending Balance	(721.4)	(754.1)	(721.4)	(754.1)
Translation Adjustments
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance			(65.7)	(11.2)
Other comprehensive loss before reclassifications			(3.7)	(18.1)
Amounts reclassified from accumulated other comprehensive loss			0.0	0.0
Amounts reclassified due to the disposition of businesses			(1.1)	13.1
Other comprehensive (loss) income			(4.8)	(5.0)
Ending Balance	(70.5)	(16.2)	(70.5)	(16.2)
AOCI Attributable to Parent
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance			(793.2)	(773.6)
Other comprehensive loss before reclassifications			(60.4)	(18.1)
Amounts reclassified from accumulated other comprehensive loss			61.6	4.4
Amounts reclassified due to the disposition of businesses			0.1	16.9
Other comprehensive (loss) income			1.3	3.2
Ending Balance	$ (791.9)	(770.4)	$ (791.9)	(770.4)
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				0.0
Amounts reclassified due to the disposition of businesses				0.0
Other comprehensive (loss) income				0.0
Ending Balance		$ (0.1)		$ (0.1)