GUARANTOR FINANCIAL STATEMENTS (Condensed Consolidated Cash Flow Statement) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Condensed Cash Flow Statements [Line Items]
Revenues	$ 3,911	$ 3,153	$ 3,546	$ 3,792	$ 3,684	$ 4,908	$ 5,168	$ 4,868	$ 14,402	$ 18,628	$ 16,403
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	2,278				4,455				2,278	4,455	4,710	$ 4,420
Cash flow from operating activities:
Net (loss) income	43	(234)	(74)	76	378	664	1,035	817	(189)	2,894	2,095
Costs and Expenses									13,311	13,874	12,713
Operating income (loss)	775	(38)	33	321	316	1,315	1,664	1,459	1,091	4,754	3,690
Interest expense, net									(620)	(945)	(801)
Other Operating Income (Expense) Including Gain (Loss) on Early Extinguishment of Debt									(138)	76
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest									306	3,892	2,902
Provision for income taxes									510	991	883
Net (loss) income from continuing operations	42	(235)	(74)	75	374	668	1,039	828	(192)	2,909	2,029
Net income (loss) from discontinued operations	1	1	0	1	4	(4)	(4)	(11)	3	(15)	66
Net income from continuing operations attributable to noncontrolling interests									(50)	(292)	(274)
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Noncontrolling Interest									0	0	4
Net (loss) income attributable to common stockholders	9	$ (207)	$ (72)	$ 31	485	$ 556	$ 869	$ 692	(239)	2,602	1,817
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent									(71)	(33)	61
Total comprehensive income (loss) attributable to common stockholders									(310)	2,569	1,878
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Depreciation, depletion and amortization									1,412	1,754	1,714
Equity in affiliated companies’ net earnings									12	8	10
Net cash provided by (used in) operating activities									1,482	3,863	4,666
Cash flow from investing activities:
Capital expenditures									(2,652)	(1,971)	(1,410)
Acquisition of PT Rio Tinto Indonesia									0	(3,500)	0
Intercompany loans									0	0	0
Dividends from (investments in) consolidated subsidiaries									(2)	0	0
Other, net									551	453
Other, net											89
Net cash provided by (used in) investing activities									(2,103)	(5,018)	(1,321)
Cash flow from financing activities:
Proceeds from debt									1,879	632	955
Repayments of debt									(3,197)	(2,717)	(3,812)
Intercompany loans									0	0	0
Net proceeds from sale of common stock										3,500
Cash dividends paid and distributions received, net									(208)	(496)	(176)
Other, net									(30)	(19)	(22)
Net cash (used in) provided by financing activities									(1,556)	900	(3,055)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect									(2,177)	(255)
Net decrease in cash, cash equivalents, restricted cash and restricted cash equivalents											290
Cash, cash equivalents, restricted cash and restricted cash equivalents at end of year	2,020				4,217				2,020	4,217
Reportable Legal Entities | FCX Issuer
Condensed Cash Flow Statements [Line Items]
Revenues									0	0	0
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	0				0				0	0	0	0
Cash flow from operating activities:
Net (loss) income									(239)	2,602	1,817
Costs and Expenses									25	28	39
Operating income (loss)									(25)	(28)	(39)
Interest expense, net									(337)	(388)	(467)
Other Operating Income (Expense) Including Gain (Loss) on Early Extinguishment of Debt									(22)	477
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest									(410)	68	(148)
Provision for income taxes									(58)	176	(220)
Net (loss) income from continuing operations									(239)	2,602	1,817
Net income (loss) from discontinued operations									0	0	0
Net income from continuing operations attributable to noncontrolling interests									0	0
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Noncontrolling Interest											0
Net (loss) income attributable to common stockholders									(239)	2,602	1,817
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent									(71)	(33)	61
Total comprehensive income (loss) attributable to common stockholders									(310)	2,569	1,878
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Equity in affiliated companies’ net earnings									113	2,710	1,745
Net cash provided by (used in) operating activities									443	(40)	(156)
Cash flow from investing activities:
Capital expenditures									0	(2)	0
Acquisition of PT Rio Tinto Indonesia										0
Intercompany loans									(1,299)	(832)	(777)
Dividends from (investments in) consolidated subsidiaries									2,177	2,475	3,226
Other, net									(1)	460
Other, net											0
Net cash provided by (used in) investing activities									877	2,101	2,449
Cash flow from financing activities:
Proceeds from debt									1,200	0	0
Repayments of debt									(2,202)	(1,826)	(2,281)
Intercompany loans									0	0	0
Net proceeds from sale of common stock										0
Cash dividends paid and distributions received, net									(291)	(217)	(2)
Other, net									(27)	(18)	(10)
Net cash (used in) provided by financing activities									(1,320)	(2,061)	(2,293)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect									0	0
Net decrease in cash, cash equivalents, restricted cash and restricted cash equivalents											0
Reportable Legal Entities | FM O&G LLC Guarantor
Condensed Cash Flow Statements [Line Items]
Revenues									40	59	52
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	0				0				0	0	8	10
Cash flow from operating activities:
Net (loss) income									(333)	(227)	(346)
Costs and Expenses									54	58	78
Operating income (loss)									(14)	1	(26)
Interest expense, net									(322)	(301)	(227)
Other Operating Income (Expense) Including Gain (Loss) on Early Extinguishment of Debt									0	0
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest									(336)	(298)	(248)
Provision for income taxes									(76)	(61)	108
Net (loss) income from continuing operations									(333)	(227)	(346)
Net income (loss) from discontinued operations									0	0	0
Net income from continuing operations attributable to noncontrolling interests									0	0
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Noncontrolling Interest											0
Net (loss) income attributable to common stockholders									(333)	(227)	(346)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent									0	0	0
Total comprehensive income (loss) attributable to common stockholders									(333)	(227)	(346)
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Equity in affiliated companies’ net earnings									(73)	10	10
Net cash provided by (used in) operating activities									(444)	(487)	(467)
Cash flow from investing activities:
Capital expenditures									(4)	0	(25)
Acquisition of PT Rio Tinto Indonesia										0
Intercompany loans									0	0	0
Dividends from (investments in) consolidated subsidiaries									0	0	(15)
Other, net									104	6
Other, net											57
Net cash provided by (used in) investing activities									100	6	17
Cash flow from financing activities:
Proceeds from debt									0	0	0
Repayments of debt									0	(53)	(205)
Intercompany loans									344	526	663
Net proceeds from sale of common stock										0
Cash dividends paid and distributions received, net									0	0	0
Other, net									0	0	(10)
Net cash (used in) provided by financing activities									344	473	448
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect									0	(8)
Net decrease in cash, cash equivalents, restricted cash and restricted cash equivalents											(2)
Reportable Legal Entities | Non-Guarantor Subsidiaries
Condensed Cash Flow Statements [Line Items]
Revenues									14,362	18,569	16,351
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	2,278				4,455				2,278	4,455	4,702	4,410
Cash flow from operating activities:
Net (loss) income									(432)	3,004	2,039
Costs and Expenses									13,244	13,798	12,586
Operating income (loss)									1,118	4,771	3,765
Interest expense, net									(494)	(734)	(455)
Other Operating Income (Expense) Including Gain (Loss) on Early Extinguishment of Debt									(95)	77
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest									528	4,112	3,308
Provision for income taxes									642	874	998
Net (loss) income from continuing operations									(435)	3,019	1,973
Net income (loss) from discontinued operations									3	(15)	66
Net income from continuing operations attributable to noncontrolling interests									(86)	(68)
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Noncontrolling Interest											4
Net (loss) income attributable to common stockholders									(518)	2,936	1,885
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent									(71)	(33)	61
Total comprehensive income (loss) attributable to common stockholders									(589)	2,903	1,946
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Equity in affiliated companies’ net earnings									(321)	(219)	(337)
Net cash provided by (used in) operating activities									1,483	4,390	5,289
Cash flow from investing activities:
Capital expenditures									(2,648)	(1,969)	(1,385)
Acquisition of PT Rio Tinto Indonesia										(3,500)
Intercompany loans									0	0	0
Dividends from (investments in) consolidated subsidiaries									96	84	120
Other, net									448	(13)
Other, net											32
Net cash provided by (used in) investing activities									(2,104)	(5,398)	(1,233)
Cash flow from financing activities:
Proceeds from debt									679	632	955
Repayments of debt									(995)	(838)	(1,326)
Intercompany loans									955	306	114
Net proceeds from sale of common stock										3,710
Cash dividends paid and distributions received, net									(2,172)	(3,032)	(3,440)
Other, net									(23)	(17)	(67)
Net cash (used in) provided by financing activities									(1,556)	761	(3,764)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect									(2,177)	(247)
Net decrease in cash, cash equivalents, restricted cash and restricted cash equivalents											292
Eliminations
Condensed Cash Flow Statements [Line Items]
Revenues									0	0	0
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	$ 0				$ 0				0	0	0	$ 0
Cash flow from operating activities:
Net (loss) income									815	(2,485)	(1,415)
Costs and Expenses									(12)	(10)	10
Operating income (loss)									12	10	(10)
Interest expense, net									533	478	348
Other Operating Income (Expense) Including Gain (Loss) on Early Extinguishment of Debt									(21)	(478)
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest									524	10	(10)
Provision for income taxes									2	2	(3)
Net (loss) income from continuing operations									815	(2,485)	(1,415)
Net income (loss) from discontinued operations									0	0	0
Net income from continuing operations attributable to noncontrolling interests									36	(224)
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Noncontrolling Interest											0
Net (loss) income attributable to common stockholders									851	(2,709)	(1,539)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent									71	33	(61)
Total comprehensive income (loss) attributable to common stockholders									922	(2,676)	(1,600)
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Equity in affiliated companies’ net earnings									293	(2,493)	(1,408)
Net cash provided by (used in) operating activities									0	0	0
Cash flow from investing activities:
Capital expenditures									0	0	0
Acquisition of PT Rio Tinto Indonesia										0
Intercompany loans									1,299	832	777
Dividends from (investments in) consolidated subsidiaries									(2,275)	(2,559)	(3,331)
Other, net									0	0
Other, net											0
Net cash provided by (used in) investing activities									(976)	(1,727)	(2,554)
Cash flow from financing activities:
Proceeds from debt									0	0	0
Repayments of debt									0	0	0
Intercompany loans									(1,299)	(832)	(777)
Net proceeds from sale of common stock										(210)
Cash dividends paid and distributions received, net									2,255	2,753	3,266
Other, net									20	16	65
Net cash (used in) provided by financing activities									976	1,727	2,554
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect									0	0
Net decrease in cash, cash equivalents, restricted cash and restricted cash equivalents											0
Freeport-McMoRan Oil & Gas
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Net gain on sales of assets										$ (27)
Cash flow from investing activities:
Proceeds from sales									$ 36		$ 80