Comprehensive Income - Schedule of Changes in Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Accumulated Other Comprehensive Income Loss [Line Items]
Balance at Beginning of Period	$ (773.6)	$ (488.1)
Other comprehensive loss before reclassifications	(54.6)	(15.1)
Amounts reclassified from accumulated other comprehensive loss	6.7	3.4
Amounts reclassified due to disposition of an operating entity	16.9
Net change in accumulated other comprehensive loss	(31.0)	(11.7)
Balance at End of Period	(804.6)	(499.8)
Changes in the Fair Value of Derivatives
Accumulated Other Comprehensive Income Loss [Line Items]
Balance at Beginning of Period	(0.1)	(0.2)
Amounts reclassified from accumulated other comprehensive loss	0.1	0.1
Net change in accumulated other comprehensive loss	0.1	0.1
Balance at End of Period		(0.1)
Pension and Other Postretirement Benefits Plan Cost
Accumulated Other Comprehensive Income Loss [Line Items]
Balance at Beginning of Period	(762.3)	(521.4)
Amounts reclassified from accumulated other comprehensive loss	6.6	3.3
Amounts reclassified due to disposition of an operating entity	3.8
Net change in accumulated other comprehensive loss	10.4	3.3
Balance at End of Period	(751.9)	(518.1)
Translation Adjustments
Accumulated Other Comprehensive Income Loss [Line Items]
Balance at Beginning of Period	(11.2)	33.5
Other comprehensive loss before reclassifications	(54.6)	(15.1)
Amounts reclassified due to disposition of an operating entity	13.1
Net change in accumulated other comprehensive loss	(41.5)	(15.1)
Balance at End of Period	$ (52.7)	$ 18.4