Commitments and Contingencies - Additional Information (Detail) $ in Millions	6 Months Ended
Jun. 30, 2016 USD ($)
Commitments and Contingencies Disclosure [Abstract]
Environmental liabilities estimated remediation costs	$ 44
Majority Shareholder Ownership Percentage Minimum	80.00%
Underfunded Pension Obligation If Pension Plans Voluntarily Terminated By Affiliate	$ 91

High-end estimate of the reasonably possible loss exposure in excess of the amount accrued for remediation, site restoration, postclosure, monitoring commitments, or other exit costs associated with the sale, disposal or abandonment of a particular property resulting from unanticipated contamination of the assets.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 5.Y.Q4)
-URI http://asc.fasb.org/extlink&oid=27011672&loc=d3e149879-122751

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 5
-Section Y
-Paragraph Question 4

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration