Amount before tax of gain (loss) recognized on the sale or disposal of a disposal group. Excludes discontinued operations.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Percent of net assets at close of period. For schedules of investments that are categorized, each category has a percent of net assets for the aggregated value of the Investments in the category.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition

This element represents the cash inflow during the period from the sale of a component of the entity.

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DISPOSITIONS AND ACQUISITIONS (Morenci) (Details) - USD ($) $ in Millions		12 Months Ended
	May 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net gain on sales of assets		$ 81	$ 649	$ 39
Morenci
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Ownership percentage	85.00%
Proceeds from divestiture, net	$ 1,000
Net gain on sales of assets	$ 576
Morenci \| Sumitomo Metal Mining Co., Ltd.
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Ownership percentage	15.00%
Morenci \| SMM Morenci Inc. [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Ownership percentage			13.00%
Morenci
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Ownership percentage		72.00%
Morenci \| Sumitomo Metal Mining Co., Ltd.
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Ownership percentage		15.00%
Morenci \| SMM Morenci Inc. [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Ownership percentage		13.00%