DEBT - Debt Extinguishment (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Nov. 30, 2014	Mar. 31, 2013	Feb. 28, 2012
Debt Instruments [Line Items]
Debt Instrument, Face Amount			$ 2,342,000,000
Debt Issuance Costs, Net	$ (69,000,000)	$ (85,000,000)
Liabilities, Fair Value Adjustment	58,000,000	97,000,000
Gain (Loss) on Extinguishment of Debt	7,000,000	21,000,000	26,000,000
Senior Notes [Member]
Debt Instruments [Line Items]
Debt Instrument, Face Amount	454,000,000	1,234,000,000	407,000,000		$ 6,500,000,000
Debt Issuance Costs, Net	(26,000,000)		(4,000,000)
Liabilities, Fair Value Adjustment		49,000,000	151,000,000
Extinguishment of Debt, Amount	480,000,000	1,283,000,000	403,000,000
Extinguishment Of Debt, Redemption Value	470,000,000	1,257,000,000	349,000,000
Gain (Loss) on Extinguishment of Debt	10,000,000	26,000,000	54,000,000
Gains (losses) primarily associated with modification of credit facility	3,000,000	(5,000,000)
Losses related to deferred debt issuance costs and senior note exchange offer			28,000,000
Senior Notes [Member] | 2.30% Senior Notes Due 2017
Debt Instruments [Line Items]
Debt Instrument, Face Amount			20,000,000	$ 750,000,000
Debt Issuance Costs, Net			0
Extinguishment of Debt, Amount			20,000,000
Extinguishment Of Debt, Redemption Value			20,000,000
Gain (Loss) on Extinguishment of Debt			0
Senior Notes [Member] | 2.375% Senior Notes due March 2018 [Member]
Debt Instruments [Line Items]
Debt Instrument, Face Amount		74,000,000	18,000,000		1,500,000,000
Debt Issuance Costs, Net			0
Liabilities, Fair Value Adjustment		0
Extinguishment of Debt, Amount		74,000,000	18,000,000
Extinguishment Of Debt, Redemption Value		74,000,000	18,000,000
Gain (Loss) on Extinguishment of Debt		0	0
Senior Notes [Member] | 6.125% Senior Notes due 2019 [Member]
Debt Instruments [Line Items]
Debt Instrument, Face Amount		179,000,000	237,000,000
Liabilities, Fair Value Adjustment		5,000,000
Extinguishment of Debt, Amount		184,000,000
Extinguishment Of Debt, Redemption Value		182,000,000
Gain (Loss) on Extinguishment of Debt		2,000,000
Senior Notes [Member] | 6.5% Senior Notes due 2020 [Member]
Debt Instruments [Line Items]
Debt Instrument, Face Amount		552,000,000	617,000,000
Liabilities, Fair Value Adjustment		23,000,000
Extinguishment of Debt, Amount		575,000,000
Extinguishment Of Debt, Redemption Value		562,000,000
Gain (Loss) on Extinguishment of Debt		13,000,000
Senior Notes [Member] | 6.625% Senior Notes due 2021 [Member]
Debt Instruments [Line Items]
Debt Instrument, Face Amount		228,000,000	261,000,000
Liabilities, Fair Value Adjustment		12,000,000
Extinguishment of Debt, Amount		240,000,000
Extinguishment Of Debt, Redemption Value		234,000,000
Gain (Loss) on Extinguishment of Debt		6,000,000
Senior Notes [Member] | 6.75% Senior Notes due 2022 [Member]
Debt Instruments [Line Items]
Debt Instrument, Face Amount	404,000,000		449,000,000
Debt Issuance Costs, Net	(22,000,000)
Extinguishment of Debt, Amount	426,000,000
Extinguishment Of Debt, Redemption Value	418,000,000
Gain (Loss) on Extinguishment of Debt	8,000,000
Senior Notes [Member] | 3.55% Senior Notes Due 2022 [Member]
Debt Instruments [Line Items]
Debt Instrument, Face Amount			108,000,000			$ 2,000,000,000
Debt Issuance Costs, Net			(1,000,000)
Extinguishment of Debt, Amount			107,000,000
Extinguishment Of Debt, Redemption Value			96,000,000
Gain (Loss) on Extinguishment of Debt			11,000,000
Senior Notes [Member] | 3.875% Senior Notes due March 2023 [Member]
Debt Instruments [Line Items]
Debt Instrument, Face Amount			77,000,000		2,000,000,000
Debt Issuance Costs, Net			0
Extinguishment of Debt, Amount			77,000,000
Extinguishment Of Debt, Redemption Value			68,000,000
Gain (Loss) on Extinguishment of Debt			9,000,000
Senior Notes [Member] | Senior Notes due 2034 5 point 4 percent [Member]
Debt Instruments [Line Items]
Debt Instrument, Face Amount			50,000,000	$ 800,000,000
Debt Issuance Costs, Net			(1,000,000)
Extinguishment of Debt, Amount			49,000,000
Extinguishment Of Debt, Redemption Value			41,000,000
Gain (Loss) on Extinguishment of Debt			8,000,000
Senior Notes [Member] | 5.450% Senior Notes due March 2043 [Member]
Debt Instruments [Line Items]
Debt Instrument, Face Amount			134,000,000		$ 2,000,000,000
Debt Issuance Costs, Net			(2,000,000)
Extinguishment of Debt, Amount			132,000,000
Extinguishment Of Debt, Redemption Value			106,000,000
Gain (Loss) on Extinguishment of Debt			26,000,000
Senior Notes [Member] | 6.875% Senior Notes due 2023 [Member]
Debt Instruments [Line Items]
Debt Instrument, Face Amount			$ 778,000,000
Freeport-McMoRan Oil & Gas LLC [Member] | Senior Notes [Member] | 6.125% Senior Notes due 2019 [Member]
Debt Instruments [Line Items]
Debt Instrument, Face Amount		58,000,000
Liabilities, Fair Value Adjustment		2,000,000
Extinguishment of Debt, Amount		60,000,000
Extinguishment Of Debt, Redemption Value		59,000,000
Gain (Loss) on Extinguishment of Debt		1,000,000
Freeport-McMoRan Oil & Gas LLC [Member] | Senior Notes [Member] | 6.5% Senior Notes due 2020 [Member]
Debt Instruments [Line Items]
Debt Instrument, Face Amount		65,000,000
Liabilities, Fair Value Adjustment		3,000,000
Extinguishment of Debt, Amount		68,000,000
Extinguishment Of Debt, Redemption Value		66,000,000
Gain (Loss) on Extinguishment of Debt		2,000,000
Freeport-McMoRan Oil & Gas LLC [Member] | Senior Notes [Member] | 6.625% Senior Notes due 2021 [Member]
Debt Instruments [Line Items]
Debt Instrument, Face Amount		33,000,000
Liabilities, Fair Value Adjustment		2,000,000
Extinguishment of Debt, Amount		35,000,000
Extinguishment Of Debt, Redemption Value		34,000,000
Gain (Loss) on Extinguishment of Debt		1,000,000
Freeport-McMoRan Oil & Gas LLC [Member] | Senior Notes [Member] | 6.75% Senior Notes due 2022 [Member]
Debt Instruments [Line Items]
Debt Instrument, Face Amount		45,000,000
Liabilities, Fair Value Adjustment		2,000,000
Extinguishment of Debt, Amount		47,000,000
Extinguishment Of Debt, Redemption Value		46,000,000
Gain (Loss) on Extinguishment of Debt		$ 1,000,000
Freeport-McMoRan Oil & Gas | Senior Notes [Member] | 6.875% Senior Notes due 2023 [Member]
Debt Instruments [Line Items]
Debt Instrument, Face Amount	50,000,000
Debt Issuance Costs, Net	(4,000,000)
Extinguishment of Debt, Amount	54,000,000
Extinguishment Of Debt, Redemption Value	52,000,000
Gain (Loss) on Extinguishment of Debt	$ 2,000,000