Commitments and Contingencies - Changes in Accrued Environmental Remediation and Related Costs (Detail) - USD ($) $ in Millions	6 Months Ended
Jun. 30, 2018	Jun. 30, 2018	Dec. 31, 2017
Environmental Remediation Obligations [Abstract]
Balance at the beginning of the year	$ 117.5
Additions charged to expense, net	4.5
Payments, net	(1.1)
Balance at the end of period	120.9
Amounts recognized in our Condensed Consolidated Balance Sheet at the end of the period:
Current liabilities		$ 19.6	$ 6.8
Noncurrent liabilities		101.3	110.7
Total	$ 117.5	$ 120.9	$ 117.5

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

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Amount of cash outflow to settle environmental loss contingencies.

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Carrying value of the obligation (known or estimated) arising from requirements to perform activities to remediate one or more sites, payable in twelve months or in the next operating cycle if longer.

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Carrying value of the obligation (known or estimated) arising from requirements to perform activities to remediate one or more sites, payable after twelve months or beyond the next operating cycle if longer.

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The amount added to the accrual and charged to expense for newly incurred environmental loss contingencies and revisions to existing environmental loss contingencies. These additions include remediation expense and interest accretion. These additions do not relate to changes in the environmental accrual related to a business acquisition or divestiture, to currency movements, or revisions in previously existing estimates not charged to expense.

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Accrued environmental loss contingencies.

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