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Acquisitions and Divestitures - Additional Information (Detail) $ in Millions	1 Months Ended		3 Months Ended		4 Months Ended	6 Months Ended
	Mar. 31, 2017 USD ($)	Apr. 30, 2016 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)	Apr. 30, 2016 USD ($) Employees	Jun. 30, 2017 USD ($) Employees	Jun. 30, 2016 USD ($)
Business Acquisition [Line Items]
Third-party sale generated in last annual period prior to divestiture			$ 3,261	$ 3,234		$ 6,453	$ 6,289
LISI MEDICAL [Member]
Business Acquisition [Line Items]
Cash received on sale of operations		$ 102
Sale of Remmele Medical business, net of transaction costs		$ 99
Slim Aluminium [Member]
Business Acquisition [Line Items]
Third-party sale generated in last annual period prior to divestiture						$ 37	$ 72
Number of employees | Employees						312
Cash expense related to sale of rolling mill	$ 10
Third party guarantee with a fair value related to environmental remediation	$ 5
Slim Aluminium [Member] | Restructuring and Other Charges [Member]
Business Acquisition [Line Items]
Loss on sale of rolling mill						$ 60
RTI [Member]
Business Acquisition [Line Items]
Third-party sale generated in last annual period prior to divestiture					$ 20
Number of employees | Employees					330

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
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-Section 45
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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
-Topic 225
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