OTHER LIABILITIES, INCLUDING EMPLOYEE BENEFITS (Penion Plans) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($) Rp / $	Dec. 31, 2017 USD ($) Rp / $	Dec. 31, 2016 USD ($)
Domestic Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Benefit Obligation	$ 2,230	$ 2,343	$ 2,135
Discount rate	4.40%	3.70%	4.40%
Expected return on plan assets	6.50%
Estimated future average expected rate of return on passively managed pension assets	6.00%
Estimated future average expected premium on actively managed pension assets	0.50%
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)	$ 124	$ (188)
Service cost	44	44	$ 27
Interest cost	84	91	93
Defined Benefit Plan, Benefit Obligation, Foreign Currency Translation Gain (Loss)	1	(3)
Defined Benefit Plan, Benefit Obligation, Special and Contractual Termination Benefits	0	0
Defined Benefit Plan, Benefit Obligation, Benefits Paid	120	118
Total pension plan net assets	1,433	1,588	1,329
Actual return on plan assets	(104)	230
Employer contributions	70	145
Foreign exchange (losses) gains	(1)	2
Defined Benefit Plan, Plan Assets, Benefits Paid	120	118
Defined Benefit Plan, Funded (Unfunded) Status of Plan	(797)	(755)
Accumulated benefit obligation	$ 2,101	$ 2,218
Rate of compensation increase	3.25%	3.25%
Other assets	$ 7	$ 11
Accounts payable and accrued liabilities	4	4
Liability, Defined Benefit Plan, Noncurrent	800	762
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position	$ (797)	(755)
Domestic Plan [Member] | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Target allocation percentage of assets	41.00%
Domestic Plan [Member] | Fixed Income Investments
Defined Benefit Plan Disclosure [Line Items]
Target allocation percentage of assets	51.00%
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	$ 220	$ 240	$ 374
Discount rate	8.25%	6.75%	8.25%
Expected return on plan assets	7.75%
Foreign currency exchange rate | Rp / $	14,409	13,480
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)	$ 19	$ 61
Service cost	13	20	$ 27
Interest cost	14	23	29
Defined Benefit Plan, Benefit Obligation, Foreign Currency Translation Gain (Loss)	15	2
Defined Benefit Plan, Benefit Obligation, Special and Contractual Termination Benefits	0	(62)
Defined Benefit Plan, Benefit Obligation, Benefits Paid	13	52
Total pension plan net assets	238	269	$ 284
Actual return on plan assets	(5)	11
Employer contributions	4	28
Foreign exchange (losses) gains	(17)	(2)
Defined Benefit Plan, Plan Assets, Benefits Paid	13	52
Defined Benefit Plan, Funded (Unfunded) Status of Plan	18	29
Accumulated benefit obligation	$ 181	$ 194
Rate of compensation increase	4.00%	4.00%
Other assets	$ 18	$ 29
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	18	29
FCX [Member] | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Plan Amendment	4	0
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)