Comprehensive Income - Schedule of Reclassification From Accumulated Other Comprehensive Loss (Detail) - Pension and Other Postretirement Benefits Plan Cost - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Amortization of pension and other postretirement benefits plan cost:
Net actuarial loss	[1]	$ 40.5	$ 31.9	$ 50.5
Net prior service credit	[1]	(26.9)	(25.8)	(19.7)
Curtailments and settlements	[1]	0.2	95.7	0.7
Reclassifications before tax		13.8	101.8	31.5
Income tax expense		4.9	39.3	11.7
Reclassifications, net of tax		$ 8.9	$ 62.5	$ 19.8

[1] These accumulated other comprehensive (loss) income components are included in the calculation of net periodic pension and other postretirement benefits plan (income) expense recognized in cost of sales and selling, general and administrative expenses in the Consolidated Statements of Operations (see Note 11).