OTHER ASSETS (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Schedule Of Other Assets [Line Items]
Indefinite-Lived Intangible Assets (Excluding Goodwill)	$ 215	$ 217
Intangible assetsc	306	305
Investments: [Abstract]
Assurance bond	123	120
Available-for-sale securities	30	50
Other	48	50
Disposal group, contingent consideration	234	196
Legally restricted fundsg	189	182
Long-term receivable for taxes	445	129
Rio Tinto's share of ARO	68	71
Long-term employee receivables	20	32
Other	144	130
Total other assets	2,270	1,956
Finite-Lived Intangible Assets, Accumulated Amortization	46	37
Equity in affiliated companies’ net earnings (losses)	10	11	$ (3)
PT-FI
Investments: [Abstract]
Long-term receivable for taxes	417	331
Cerro Verde
Investments: [Abstract]
Long-term receivable for taxes	185	277
PT Smelting
Investments: [Abstract]
PT Smelting	$ 61	83
Ownership percentage	25.00%
Equity in affiliated companies’ net earnings (losses)	$ 68	39
Accounts Receivable, Gross, Current	308	283
NEW MEXICO
Investments: [Abstract]
Legally restricted funds for asset retirement obligations at New Mexico mines	$ 180	$ 173

Amount of assurance bond provided for smelter development.

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Schedule Of Other Assets [Line Items]

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