FINANCIAL INSTRUMENTS (Unrealized gains losses) (Details) oz in Thousands, lb in Millions, $ in Millions		12 Months Ended
	Dec. 31, 2019 lb oz $ / lb $ / lb $ / oz	Dec. 31, 2019 USD ($) $ / lb $ / lb $ / oz	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Derivatives Not Designated as Hedging Instruments | Amounts recorded in Sales [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Embedded Derivative, Gain (Loss) on Embedded Derivative, Net		$ 54	$ (317)	$ 515
Commodity Contract [Member]
Unrealized gains (losses):
Derivative financial instruments		15	(20)	4
Hedged item – firm sales commitments		(15)	20	(4)
Realized gains (losses):
Matured derivative financial instruments		$ (8)	(22)	30
Commodity Contract [Member] | Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Nonmonetary Notional Amount, Mass | lb	54
Derivative, Average Forward Price | $ / lb	2.69	2.69
Copper Forward Contracts [Member] | Derivatives Not Designated as Hedging Instruments
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Nonmonetary Notional Amount, Mass | lb	30
Derivative, Average Forward Price | $ / lb	2.75	2.75
Copper Forward Contracts [Member] | Derivatives Not Designated as Hedging Instruments | Amounts recorded in Cost of Sales
Realized gains (losses):
Matured derivative financial instruments		$ (7)	18	(15)
Copper | Derivatives Not Designated as Hedging Instruments | Amounts recorded in Sales [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Embedded Derivative, Gain (Loss) on Embedded Derivative, Net		$ 34	(310)	489
Copper | Short [Member] | Embedded Derivative Financial Instruments [Member] | Derivatives Not Designated as Hedging Instruments
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Nonmonetary Notional Amount, Mass | lb	481
Derivative, Average Forward Price | $ / lb	2.67	2.67
Realized gains (losses):
Derivative Average Market Price | $ / lb	2.80	2.80
Copper | Long [Member] | Embedded Derivative Financial Instruments [Member] | Derivatives Not Designated as Hedging Instruments
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Nonmonetary Notional Amount, Mass | lb	129
Derivative, Average Forward Price | $ / lb	2.64	2.64
Realized gains (losses):
Derivative Average Market Price | $ / lb	2.80	2.80
Gold | Short [Member] | Embedded Derivative Financial Instruments [Member] | Derivatives Not Designated as Hedging Instruments
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Nonmonetary Notional Amount, Mass | oz	112
Derivative, Average Forward Price | $ / oz	1,471	1,471
Realized gains (losses):
Derivative Average Market Price | $ / oz	1,527	1,527
gold and other [Member] | Derivatives Not Designated as Hedging Instruments | Amounts recorded in Sales [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Embedded Derivative, Gain (Loss) on Embedded Derivative, Net		$ 20	$ (7)	$ 26