Comprehensive Income - Schedule of Reclassification From Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss)
Amortization of pension and other postretirement benefits plan cost:
Reclassifications before tax	[1]	$ 26.2	$ 40.5	$ 31.9
Accumulated Defined Benefit Plans Adjustment, Net Prior Service
Amortization of pension and other postretirement benefits plan cost:
Reclassifications before tax	[1]	(12.7)	(26.9)	(25.8)
Accumulated Defined Benefit Plans Adjustment, Curtailments and settlements
Amortization of pension and other postretirement benefits plan cost:
Reclassifications before tax	[1]	78.9	0.2	95.7
Accumulated Defined Benefit Plans Adjustment Attributable to Parent
Amortization of pension and other postretirement benefits plan cost:
Reclassifications before tax		92.4	13.8	101.8
Income tax expense		39.7	4.9	39.3
Reclassifications, net of tax		$ 52.7	$ 8.9	$ 62.5

[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 12, Retirement Plans).