BUSINESS SEGMENTS INFORMATION (Business Segments Narrative) (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Workforce Subject to Collective Bargaining Arrangements
Mining Segment Reporting Information [Line Items]
Concentration risk percentage	38.00%
Workforce Subject to Collective Bargaining Arrangements Expiring within One Year
Mining Segment Reporting Information [Line Items]
Concentration risk percentage	16.00%
North America | Inventory, Copper Metal Production | Product Concentration Risk | Morenci
Mining Segment Reporting Information [Line Items]
Concentration risk percentage	50.00%
North America | Cost of Goods, Product Line | Supplier Concentration Risk | Atlantic Copper Smelting & Refining
Mining Segment Reporting Information [Line Items]
Concentration risk percentage	10.00%
South America | Inventory, Copper Metal Production | Product Concentration Risk | Cerro Verde
Mining Segment Reporting Information [Line Items]
Concentration risk percentage	84.00%
South America | Cost of Goods, Product Line | Supplier Concentration Risk | Atlantic Copper Smelting & Refining
Mining Segment Reporting Information [Line Items]
Concentration risk percentage	7.00%
Indonesia | Cost of Goods, Product Line | Supplier Concentration Risk | Atlantic Copper Smelting & Refining
Mining Segment Reporting Information [Line Items]
Concentration risk percentage	4.00%
PT Smelting
Mining Segment Reporting Information [Line Items]
Deferred intercompany profit	25.00%
PT Smelting | Revenue from Contract with Customer Benchmark [Member]
Mining Segment Reporting Information [Line Items]
Concentration risk percentage	12.00%	13.00%	12.00%
Morenci
Mining Segment Reporting Information [Line Items]
Ownership percentage	72.00%