SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (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	Dec. 31, 2015
Schedule of Significant Accounting Policies [Line Items]
Proceeds from Other Operating Activities											$ 56
Metals inventory adjustments			$ 12						$ 4	$ 8	36
Production and delivery									11,691	10,266	10,687
Total cost of sales									13,445	11,980	17,534
Selling, general and administrative expenses									443	477	597
Exploration Expense									105	93	63
Environmental obligations and shutdown costs									89	244	14
Costs and Expenses									13,874	12,713	17,559
Operating income (loss)	$ 316	$ 1,315	$ 1,664	$ 1,459	$ 1,479	$ 928	$ 686	$ 597	4,754	3,690	(2,729)
Accrued income taxes and timing of other tax payments									(472)	457	136
Net cash (used in) provided by operating activities									3,863	4,666	3,737
Reclassification to Well, Facilities, and Equipment Based on Determination of Proved Reserves											4,900
Impairment of Oil and Gas Properties									0	0	4,317
Foreign currency transaction gains (losses), before tax									14	(5)	32
Payments for (Proceeds from) Other Investing Activities									(97)	17	11
Net cash provided by (used in) investing activities									(5,018)	(1,321)	3,553
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect									(255)	290	4,124
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Before Reclassification of Assets Held for Sale					4,631					4,631	4,403	$ 324
Other income (expense), net									76	(8)	(14)
Cumulative Effect of New Accounting Principle in Period of Adoption	0								$ 0
United States oil and gas operations
Schedule of Significant Accounting Policies [Line Items]
Capitalized interest											7
Copper
Schedule of Significant Accounting Policies [Line Items]
Percentage of ultimate copper recovery from leach stockpiles									90.00%
Percentage of copper ultimately recoverable from newly placed material on active stockpiles extracted during the first year									80.00%
PT-FI
Schedule of Significant Accounting Policies [Line Items]
Metals inventory adjustments	$ 43
Ownership percentage of subsidiary	48.76%								48.76%
Previously Reported [Member]
Schedule of Significant Accounting Policies [Line Items]
Proceeds from Other Operating Activities											48
Production and delivery										10,308	10,733
Total cost of sales										12,022	17,580
Selling, general and administrative expenses										484	607
Exploration Expense										94	64
Environmental obligations and shutdown costs										251	20
Costs and Expenses										12,770	17,622
Operating income (loss)										3,633	(2,792)
Accrued income taxes and timing of other tax payments										473
Net cash (used in) provided by operating activities										4,682	3,729
Payments for (Proceeds from) Other Investing Activities										(25)	8
Net cash provided by (used in) investing activities										(1,363)	3,550
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect										264	4,113
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Before Reclassification of Assets Held for Sale					4,447					4,447	4,245	177
Other income (expense), net										49	49
Accounting Standards Update 2017-05 [Member] | Restatement Adjustment
Schedule of Significant Accounting Policies [Line Items]
Production and delivery										(42)	(46)
Total cost of sales										(42)	(46)
Selling, general and administrative expenses										(7)	(10)
Exploration Expense										(1)	(1)
Environmental obligations and shutdown costs										(7)	(6)
Costs and Expenses										(57)	(63)
Operating income (loss)										57	63
Other income (expense), net										(57)	(63)
Accounting Standards Update 2016-18 [Member] | Restatement Adjustment
Schedule of Significant Accounting Policies [Line Items]
Proceeds from Other Operating Activities											8
Accrued income taxes and timing of other tax payments										(16)
Net cash (used in) provided by operating activities										(16)	8
Payments for (Proceeds from) Other Investing Activities										42	3
Net cash provided by (used in) investing activities										42	3
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect										26	11
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Before Reclassification of Assets Held for Sale					$ 184					$ 184	$ 158	$ 147
Accumulated Other Comprehensive Loss
Schedule of Significant Accounting Policies [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption	$ (79)								$ (79)