Comprehensive Income - Schedule of Changes in Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accumulated Other Comprehensive Income Loss [Line Items]
Balance at Beginning of Period	$ (773.6)	$ (488.1)	$ (1,029.2)
Other comprehensive income (loss) before reclassifications	(45.5)	(338.1)	520.9
Amounts reclassified from accumulated other comprehensive loss	9.0	62.6	20.2
Amounts reclassified from cumulative translation adjustment		(10.0)
Amounts reclassified due to disposition of an operating entity	16.9
Net change in accumulated other comprehensive loss	(19.6)	(285.5)	541.1
Balance at End of Period	(793.2)	(773.6)	(488.1)
Changes in the Fair Value of Derivatives
Accumulated Other Comprehensive Income Loss [Line Items]
Balance at Beginning of Period	(0.1)	(0.2)	(0.6)
Other comprehensive income (loss) before reclassifications	0.0	0.0	0.0
Amounts reclassified from accumulated other comprehensive loss	0.1	0.1	0.4
Amounts reclassified from cumulative translation adjustment		0.0
Amounts reclassified due to disposition of an operating entity	0.0
Net change in accumulated other comprehensive loss	0.1	0.1	0.4
Balance at End of Period	0.0	(0.1)	(0.2)
Pension and Other Postretirement Benefits Plan Cost
Accumulated Other Comprehensive Income Loss [Line Items]
Balance at Beginning of Period	(762.3)	(521.4)	(1,085.1)
Other comprehensive income (loss) before reclassifications	22.1	(303.4)	543.9
Amounts reclassified from accumulated other comprehensive loss	8.9	62.5	19.8
Amounts reclassified from cumulative translation adjustment		0.0
Amounts reclassified due to disposition of an operating entity	3.8
Net change in accumulated other comprehensive loss	34.8	(240.9)	563.7
Balance at End of Period	(727.5)	(762.3)	(521.4)
Translation Adjustments
Accumulated Other Comprehensive Income Loss [Line Items]
Balance at Beginning of Period	(11.2)	33.5	56.5
Other comprehensive income (loss) before reclassifications	(67.6)	(34.7)	(23.0)
Amounts reclassified from accumulated other comprehensive loss	0.0	0.0	0.0
Amounts reclassified from cumulative translation adjustment		(10.0)
Amounts reclassified due to disposition of an operating entity	13.1
Net change in accumulated other comprehensive loss	(54.5)	(44.7)	(23.0)
Balance at End of Period	$ (65.7)	$ (11.2)	$ 33.5