OTHER LIABILITIES, INCLUDING EMPLOYEE BENEFITS (Penion Plans) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($) Rp / $	Dec. 31, 2018 USD ($) Rp / $	Dec. 31, 2017 USD ($)
Domestic Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Benefit Obligation	$ 2,576	$ 2,230	$ 2,343
Discount rate	3.40%	4.40%	3.70%
Expected return on plan assets	6.25%
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)	$ (328)	$ 124
Service cost	42	44	$ 44
Interest cost	95	84	91
Defined Benefit Plan, Benefit Obligation, Foreign Currency Translation Gain (Loss)	(1)	1
Defined Benefit Plan, Benefit Obligation, Benefits Paid	120	120
Total pension plan net assets	1,677	1,433	1,588
Actual return on plan assets	289	(104)
Employer contributions	74	70
Foreign exchange gains (losses)	1	(1)
Defined Benefit Plan, Plan Assets, Benefits Paid	120	120
Defined Benefit Plan, Funded (Unfunded) Status of Plan	(899)	(797)
Accumulated benefit obligation	$ 2,414	$ 2,101
Rate of compensation increase	3.25%	3.25%
Other assets	$ 8	$ 7
Accounts payable and accrued liabilities	4	4
Liability, Defined Benefit Plan, Noncurrent	903	800
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position	$ (899)	(797)
Domestic Plan [Member] | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Target allocation percentage of assets	42.00%
Domestic Plan [Member] | Fixed Income Investments
Defined Benefit Plan Disclosure [Line Items]
Target allocation percentage of assets	50.00%
Domestic Plan [Member] | Alternative Investments
Defined Benefit Plan Disclosure [Line Items]
Target allocation percentage of assets	8.00%
SERP
Defined Benefit Plan Disclosure [Line Items]
Years of service required for annuity to equal percentage of executive's highest average compensation for any consecutive three-year period during the preceeding five years before retirement	25 years
Foreign Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Benefit Obligation	$ 217	$ 220	$ 240
Discount rate	7.25%	8.25%	6.75%
Expected return on plan assets	7.75%
Foreign currency exchange rate | Rp / $	13,832	14,409
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)	$ 27	$ 19
Service cost	12	13	$ 20
Interest cost	17	14	23
Defined Benefit Plan, Benefit Obligation, Foreign Currency Translation Gain (Loss)	(8)	15
Defined Benefit Plan, Benefit Obligation, Benefits Paid	13	13
Total pension plan net assets	254	238	$ 269
Actual return on plan assets	19	(5)
Employer contributions	0	4
Foreign exchange gains (losses)	10	(17)
Defined Benefit Plan, Plan Assets, Benefits Paid	13	13
Defined Benefit Plan, Funded (Unfunded) Status of Plan	37	18
Accumulated benefit obligation	$ 175	$ 181
Rate of compensation increase	4.00%	4.00%
Other assets	$ 37	$ 18
Accounts payable and accrued liabilities	0	0
Liability, Defined Benefit Plan, Noncurrent	0	0
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position	37	18
FCX [Member] | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Plan Amendment	0	4
PT Freeport Indonesia, Subsidiary | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Plan Amendment	$ 0	0
Measurement Input, Census Data [Member] | Domestic Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)		(33)
Measurement Input, Mortality Rate [Member] | Domestic Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)		(49)
Measurement Input, Discount Rate [Member] | Domestic Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)		$ (205)