Other Comprehensive (Loss) Income - Schedule of Reclassification From Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Reclassification, net of tax	$ 29.3	$ (1.8)
Investment and other expense (income) -net	48.7	(0.1)
Net Actuarial Loss | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Cost of sales; Selling, general and administrative expenses	1.7	7.8
Net Prior Service Credit | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Cost of sales; Selling, general and administrative expenses	(0.7)	(4.0)
Amortization of Pension and Other Postretirement Benefits Plan Cost
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Reclassifications before tax	1.0	3.8
Income tax expense (benefit)	0.3	5.6
Reclassification, net of tax	0.7	$ (1.8)
Available-for-Sale Securities, Loss on Equity Securities
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Reclassifications before tax	46.6
Income tax expense (benefit)	18.0
Reclassification, net of tax	28.6
Available-for-Sale Securities, Loss on Equity Securities | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Investment and other expense (income) -net	$ 46.6