FAIR VALUE MEASUREMENTS (Tables)

12 Months Ended

Dec. 31, 2019

Disclosure of fair value measurement of liabilities



Fair Value Measurements
At December 31, 2019	Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs		Aggregate Fair Value
	(Level 1)		(Level 2)		(Level 3)
Cash and equivalents		$3,314		$—		$—		$3,314
Other investments	258		—		—		258
Derivatives	—		1		—		1
Receivables from provisional copper and gold sales	—		68		—		68
		$3,572		$69		$—		$3,641

Fair Value Measurements
At December 31, 2018	Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs		Aggregate Fair Value
	(Level 1)		(Level 2)		(Level 3)
Cash and equivalents		$1,571		$—		$—		$1,571
Other investments	209		—		—		209
Derivatives	—		—		—		—
Receivables from provisional copper and gold sales	—		76		—		76
		$1,780		$76		$—		$1,856



	At December 31, 2019				At December 31, 2018
	Carrying amount		Estimated fair value		Carrying amount		Estimated fair value
Financial assets
Other assets¹		$612		$612		$559		$559
Other investments²	258		258		209		209
Derivative assets	1		1		3		3
		$871		$871		$771		$771
Financial liabilities
Debt³		$5,536		$6,854		$5,738		$6,183
Derivative liabilities	—		—		3		3
Other liabilities	209		209		297		297
		$5,745		$7,063		$6,038		$6,483


¹	Includes restricted cash and amounts due from our partners.


²	Recorded at fair value. Quoted market prices are used to determine fair value.

Debt is generally recorded at amortized cost except for obligations that are designated in a fair-value hedge relationship, in which case the carrying amount is adjusted for changes in fair value of the hedging instrument in periods when a hedge relationship exists. The fair value of debt is primarily determined using quoted market prices. Balance includes both current and long-term portions of debt.

Disclosure of fair value measurement of assets



	Quoted prices in active markets for identical assets	Significant other observable inputs	Significant unobservable inputs	Aggregate fair value
	(Level 1)	(Level 2)	(Level 3)	Aggregate fair value
Property, plant and equipment¹	—	—	130	130

¹ Property, plant and equipment were written down by $389 million, which was included in earnings in this period.



Fair Value Measurements
At December 31, 2019	Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs		Aggregate Fair Value
	(Level 1)		(Level 2)		(Level 3)
Cash and equivalents		$3,314		$—		$—		$3,314
Other investments	258		—		—		258
Derivatives	—		1		—		1
Receivables from provisional copper and gold sales	—		68		—		68
		$3,572		$69		$—		$3,641

Fair Value Measurements
At December 31, 2018	Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs		Aggregate Fair Value
	(Level 1)		(Level 2)		(Level 3)
Cash and equivalents		$1,571		$—		$—		$1,571
Other investments	209		—		—		209
Derivatives	—		—		—		—
Receivables from provisional copper and gold sales	—		76		—		76
		$1,780		$76		$—		$1,856



	At December 31, 2019				At December 31, 2018
	Carrying amount		Estimated fair value		Carrying amount		Estimated fair value
Financial assets
Other assets¹		$612		$612		$559		$559
Other investments²	258		258		209		209
Derivative assets	1		1		3		3
		$871		$871		$771		$771
Financial liabilities
Debt³		$5,536		$6,854		$5,738		$6,183
Derivative liabilities	—		—		3		3
Other liabilities	209		209		297		297
		$5,745		$7,063		$6,038		$6,483


¹	Includes restricted cash and amounts due from our partners.


²	Recorded at fair value. Quoted market prices are used to determine fair value.