STOCKHOLDERS' EQUITY AND STOCK-BASED COMPENSATION (Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance, stockholders' equity	$ 9,798
Ending balance, stockholders' equity	9,298	$ 9,798
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption		(79)
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), after Reclassification Adjustment, before Tax	(111)	(87)	$ 52
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance, stockholders' equity	(615)	(494)	(554)
OCI, before Reclassifications, Net of Tax, Attributable to Parent	(118)	(84)	7
Other Comprehensive Income (Loss), Reclassification, Pension and Other Postretirement Benefit Plans, Net Gain (Loss) Recognized in Net Periodic Benefit Cost, Net of Tax	47	48	53
Ending balance, stockholders' equity	(686)	(615)	(494)
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption		0
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance, stockholders' equity	0	(3)	(4)
OCI, before Reclassifications, Net of Tax, Attributable to Parent	0	0	1
Other Comprehensive Income (Loss), Reclassification, Pension and Other Postretirement Benefit Plans, Net Gain (Loss) Recognized in Net Periodic Benefit Cost, Net of Tax	0	3	0
Ending balance, stockholders' equity	0	0	(3)
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption		0
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance, stockholders' equity	10	10	10
OCI, before Reclassifications, Net of Tax, Attributable to Parent	0	0	0
Other Comprehensive Income (Loss), Reclassification, Pension and Other Postretirement Benefit Plans, Net Gain (Loss) Recognized in Net Periodic Benefit Cost, Net of Tax	0	0	0
Ending balance, stockholders' equity	10	10	10
Accumulated Other Comprehensive Loss
Cumulative Effect of New Accounting Principle in Period of Adoption		(79)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance, stockholders' equity	(605)	(487)	(548)
OCI, before Reclassifications, Net of Tax, Attributable to Parent	(118)	(84)	8
Other Comprehensive Income (Loss), Reclassification, Pension and Other Postretirement Benefit Plans, Net Gain (Loss) Recognized in Net Periodic Benefit Cost, Net of Tax	47	51	53
Ending balance, stockholders' equity	(676)	(605)	(487)
Accumulated Defined Benefit Plans Adjustment Attributable to Noncontrolling Interest [Member]
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	8	(4)	(45)
Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Attributable to Parent [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Other Comprehensive Income (Loss), Reclassification, Pension and Other Postretirement Benefit Plans, Net Gain (Loss) Recognized in Net Periodic Benefit Cost, Net of Tax	$ 0	0	$ (5)
PT Freeport Indonesia [Member] | Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Actuarial (losses) gains arising during the period, net of taxes		(6)
PT Freeport Indonesia [Member] | AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Actuarial (losses) gains arising during the period, net of taxes		0
PT Freeport Indonesia [Member] | Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Actuarial (losses) gains arising during the period, net of taxes		0
PT Freeport Indonesia [Member] | Accumulated Other Comprehensive Loss
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Actuarial (losses) gains arising during the period, net of taxes		$ (6)