DISPOSITIONS AND ACQUISITIONS (TF Holdings Limited) (Details) $ in Millions			3 Months Ended								12 Months Ended
	Dec. 21, 2018 USD ($)	Nov. 16, 2016 USD ($)	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Jan. 31, 2020 USD ($)	Nov. 30, 2016 USD ($) $ / lb	Nov. 15, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from divestiture, net	$ 350
Other assets			$ 1,885				$ 2,172				$ 1,885	$ 2,172
Net (loss) gain on disposal											3	(15)	$ 57
Net income (loss) from discontinued operations			$ 1	$ 1	$ 0	$ 1	4	$ (4)	$ (4)	$ (11)	3	(15)	66
Disposed of by Sale, Discontinued Operations | TF Holdings Limited
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Discontinued Operation, Income (Loss) from Discontinued Operation During Phase-out Period, before Income Tax											0	0	13
Proceeds from divestiture, net		$ 2,650
Contingent receivable															$ 120
Other assets							$ 57					57
Chainge in fair value of contingent consideration											3	(17)	61
Net (loss) gain on disposal											3	(15)	57
Discontinued Operation, Income (Loss) from Discontinued Operation, before Income Tax											3	(15)	70
Discontinued Operation, Tax Effect of Discontinued Operation											0	0	4
Net income (loss) from discontinued operations											3	(15)	66
TF Holdings Limited
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Ownership percentage																70.00%
Copper | Disposed of by Sale, Discontinued Operations | TF Holdings Limited
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Contingent receivable															60
Cobalt | Disposed of by Sale, Discontinued Operations | TF Holdings Limited
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Contingent receivable															$ 60
Contingent consideration, reference threshold, price per barrel (in us dollars per pound) | $ / lb															20
Eliminations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net income (loss) from discontinued operations											$ 0	$ 0	$ 0
Subsequent Event [Member] | Cobalt | Disposed of by Sale, Discontinued Operations | TF Holdings Limited
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Contingent receivable														$ 60
Maximum | Copper | Disposed of by Sale, Discontinued Operations | TF Holdings Limited
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Contingent consideration, reference threshold, price per barrel (in us dollars per pound) | $ / lb															3.50