DEBT - Debt Extinguishment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Debt Instruments [Line Items]
Gain (Loss) on Extinguishment of Debt	$ (27)	$ 7	$ 21
Senior Notes [Member]
Debt Instruments [Line Items]
Debt Instrument, Face Amount	2,145	454	1,234
DebtIssuanceCostsandFairValueAdjustments	30	26	49
Extinguishment of Debt, Amount	2,175	480	1,283
Extinguishment Of Debt, Redemption Value	2,201	470	1,257
Gain (Loss) on Extinguishment of Debt	26	(10)	(26)
Senior Notes [Member] | 3.100% Senior Notes due March 2020 [Member]
Debt Instruments [Line Items]
Debt Instrument, Face Amount	1,000
DebtIssuanceCostsandFairValueAdjustments	(2)
Extinguishment of Debt, Amount	998
Extinguishment Of Debt, Redemption Value	1,003
Gain (Loss) on Extinguishment of Debt	5
Senior Notes [Member] | Senior Notes Due 2022 [Member]
Debt Instruments [Line Items]
Debt Instrument, Face Amount		404
DebtIssuanceCostsandFairValueAdjustments		22
Extinguishment of Debt, Amount		426
Extinguishment Of Debt, Redemption Value		418
Gain (Loss) on Extinguishment of Debt		(8)
Senior Notes [Member] | 2.375% Senior Notes due March 2018 [Member]
Debt Instruments [Line Items]
Debt Instrument, Face Amount			74
DebtIssuanceCostsandFairValueAdjustments			0
Extinguishment of Debt, Amount			74
Extinguishment Of Debt, Redemption Value			74
Gain (Loss) on Extinguishment of Debt			0
Senior Notes [Member] | 6.125% Senior Notes due 2019 [Member]
Debt Instruments [Line Items]
Debt Instrument, Face Amount			179
DebtIssuanceCostsandFairValueAdjustments			5
Extinguishment of Debt, Amount			184
Extinguishment Of Debt, Redemption Value			182
Gain (Loss) on Extinguishment of Debt			(2)
Senior Notes [Member] | 6.5% Senior Notes due 2020 [Member]
Debt Instruments [Line Items]
Debt Instrument, Face Amount			552
DebtIssuanceCostsandFairValueAdjustments			23
Extinguishment of Debt, Amount			575
Extinguishment Of Debt, Redemption Value			562
Gain (Loss) on Extinguishment of Debt			(13)
Senior Notes [Member] | 6.625% Senior Notes due 2021 [Member]
Debt Instruments [Line Items]
Debt Instrument, Face Amount			228
DebtIssuanceCostsandFairValueAdjustments			12
Extinguishment of Debt, Amount			240
Extinguishment Of Debt, Redemption Value			234
Gain (Loss) on Extinguishment of Debt			(6)
Senior Notes [Member] | 3.55% Senior Notes Due 2022 [Member]
Debt Instruments [Line Items]
Debt Instrument, Face Amount	12
DebtIssuanceCostsandFairValueAdjustments	0
Extinguishment of Debt, Amount	12
Extinguishment Of Debt, Redemption Value	12
Gain (Loss) on Extinguishment of Debt	0
Senior Notes [Member] | 6.875% Senior Notes due 2023 [Member]
Debt Instruments [Line Items]
Debt Instrument, Face Amount		50
DebtIssuanceCostsandFairValueAdjustments		4
Extinguishment of Debt, Amount		54
Extinguishment Of Debt, Redemption Value		52
Gain (Loss) on Extinguishment of Debt		$ (2)
Senior Notes [Member] | Senior Notes Due 2023 [Member]
Debt Instruments [Line Items]
Debt Instrument, Face Amount	728
DebtIssuanceCostsandFairValueAdjustments	34
Extinguishment of Debt, Amount	762
Extinguishment Of Debt, Redemption Value	768
Gain (Loss) on Extinguishment of Debt	6
Senior Notes [Member] | Senior Notes Due 2021 [Member]
Debt Instruments [Line Items]
Debt Instrument, Face Amount	405
DebtIssuanceCostsandFairValueAdjustments	(2)
Extinguishment of Debt, Amount	403
Extinguishment Of Debt, Redemption Value	418
Gain (Loss) on Extinguishment of Debt	$ 15
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
DebtIssuanceCostsandFairValueAdjustments			2
Extinguishment of Debt, Amount			60
Extinguishment Of Debt, Redemption Value			59
Gain (Loss) on Extinguishment of Debt			(1)
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
DebtIssuanceCostsandFairValueAdjustments			3
Extinguishment of Debt, Amount			68
Extinguishment Of Debt, Redemption Value			66
Gain (Loss) on Extinguishment of Debt			(2)
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
DebtIssuanceCostsandFairValueAdjustments			2
Extinguishment of Debt, Amount			35
Extinguishment Of Debt, Redemption Value			34
Gain (Loss) on Extinguishment of Debt			(1)
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
DebtIssuanceCostsandFairValueAdjustments			2
Extinguishment of Debt, Amount			47
Extinguishment Of Debt, Redemption Value			46
Gain (Loss) on Extinguishment of Debt			$ (1)