Other Comprehensive Income (Loss) - Schedule of Reclassification from Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Reclassification, net of tax	$ 1.7	$ (0.2)	$ 2.3	$ (4.9)
Other operating expense (income)	8.0	2.3	21.2	(2.1)
Translation Adjustments
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Reclassification, net of tax				(4.5)
Translation Adjustments | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Other operating expense (income)				(4.5)
Net Actuarial Loss | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Investment and other income-net	1.4	0.7	3.0	2.2
Net Prior Service Credit | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Investment and other income-net	(0.4)	(0.9)	(1.0)	(2.7)
Amortization of Pension and OPEB Cost
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Reclassifications before tax	1.0	(0.2)	2.0	(0.5)
Income tax expense (benefit)	0.3		0.5	(0.1)
Reclassification, net of tax	0.7	$ (0.2)	1.5	$ (0.4)
Accumulated Gain (Loss), Cash Flow Hedge, Including Noncontrolling Interest
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Reclassification, net of tax	1.0		0.8
Accumulated Gain (Loss), Cash Flow Hedge, Including Noncontrolling Interest | Reclassification out of Accumulated Other Comprehensive Income | Net Realized Loss on Derivatives
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Interest expense-net	$ 1.0		$ 0.8