DISPOSITIONS AND ACQUISITIONS (Assets Held for Sale) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Long Lived Assets Held-for-sale [Line Items]
Gain (Loss) on Disposition of Assets	$ (82)	$ (70)	$ (45)	$ (11)	$ (15)	$ (33)	$ (10)	$ (23)	$ (208)	$ (81)	$ (649)
Deferred income taxes	4,032				3,663				4,032	3,663
Property, plant, equipment and mine development costs, net	28,010				$ 22,994				28,010	22,994
Depreciation, depletion and amortization									1,754	$ 1,714	2,610
Kisanfu Exploration Project
Long Lived Assets Held-for-sale [Line Items]
Ownership percentage					56.00%					56.00%
Freeport Cobalt And Kisanfu Exploration Project
Long Lived Assets Held-for-sale [Line Items]
Gain (Loss) on Disposition of Assets											$ 110
Freeport Cobalt
Long Lived Assets Held-for-sale [Line Items]
Increase (Decrease) in Assets Held-for-sale									97
Property, plant, equipment and mine development costs, net	$ 60								$ 60
Kisanfu Exploration Project | Restatement Adjustment
Long Lived Assets Held-for-sale [Line Items]
Deferred income taxes					$ 27					$ 27
Property, plant, equipment and mine development costs, net					$ 90					$ 90