Commitments and Contingencies - Rollforward of Environmental Liability and Related Assets (Detail) - Environmental Related Matters [Member] - Liability [Member] - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019
Environmental Liability and Related Assets [Roll Forward]
Balance as of January 1	$ 61.9	$ 66.8
Changes in estimates for pre-existing accruals:
Net cash activity	(3.7)	(5.4)
Foreign currency	0.2
Balance as of December 31	58.3	61.9
Continuing Operations [Member]
Changes in estimates for pre-existing accruals:
Continuing operations	1.4	0.4
Discontinued operations	(1.4)	(0.4)
Discontinued Operations [Member]
Changes in estimates for pre-existing accruals:
Continuing operations	(1.5)	0.1
Discontinued operations	$ 1.5	$ (0.1)

Accrual For Environmental Loss Contingencies Liabilities For Currency Translation

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Changes In Pre-Existing Environmental Accruals

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Environmental Liability and Related Assets [Roll Forward]

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Total costs accrued as of the balance sheet date for environmental loss contingencies.

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Amount of expense for newly incurred environmental loss contingencies. Includes, but is not limited to, remediation expense and interest accretion.

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Amount of cash outflow to settle environmental loss contingencies.

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