Business Segments (Segment Reporting) (Details) lb in Millions, $ in Millions	1 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended
	Apr. 30, 2020 lb $ / lb	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($) segment	Jun. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)
Segment Reporting Information [Line Items]
Number of Operating Segments | segment				4
Deferred Intercompany Profit, Percentage				25.00%
Revenues		$ 3,054	$ 3,546	$ 5,852	$ 7,338
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization (Deprecated 2019-01-31)		(2,394)	(3,005)	(4,939)	(5,929)
Cost, Depreciation, Amortization and Depletion		358	352	699	699
Metals inventory adjustments		(139)	2	83	59
Selling, general and administrative expenses		(91)	(92)	(201)	(199)
Mining exploration and research expenses		18	31	34	58
Environmental obligations and shutdown costs		11	23	37	65
Net gain on sales of assets		0	8	11	(25)
Operating income (loss)		321	33	(152)	354
Interest expense, net		115	132	242	278
Provision for (benefit from) income taxes		96	(15)	36	90
Total assets		40,230	41,086	40,230	41,086	$ 40,809
Capital expenditures		527	629	1,137	1,251
Operating Segments | North America
Segment Reporting Information [Line Items]
Revenues		36	85	45	192
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization (Deprecated 2019-01-31)		(787)	(824)	(1,647)	(1,567)
Cost, Depreciation, Amortization and Depletion		89	87	181	170
Metals inventory adjustments		(89)	1	56	1
Selling, general and administrative expenses		(1)	0	(2)	(2)
Mining exploration and research expenses		1	1	2	1
Environmental obligations and shutdown costs		0	0	0	0
Net gain on sales of assets			0	0	0
Operating income (loss)		199	207	85	413
Interest expense, net		1	1	2	2
Provision for (benefit from) income taxes		0	0	0	0
Total assets		7,895	7,838	7,895	7,838
Capital expenditures		148	207	332	417
Operating Segments | South America
Segment Reporting Information [Line Items]
Revenues		577	690	1,051	1,515
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization (Deprecated 2019-01-31)		(438)	(581)	(972)	(1,120)
Cost, Depreciation, Amortization and Depletion		102	119	210	233
Metals inventory adjustments		(57)	0	3	0
Selling, general and administrative expenses		(1)	(2)	(3)	(4)
Mining exploration and research expenses		0	0	0	0
Environmental obligations and shutdown costs		0	0	0	0
Net gain on sales of assets			0	0	0
Operating income (loss)		145	59	(47)	355
Interest expense, net		20	25	48	54
Provision for (benefit from) income taxes		45	11	(33)	116
Total assets		10,146	10,270	10,146	10,270
Capital expenditures		51	47	125	108
Corporate And Eliminations
Segment Reporting Information [Line Items]
Revenues		188	471	514	927
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization (Deprecated 2019-01-31)		854	718	1,642	1,388
Cost, Depreciation, Amortization and Depletion		15	19	30	39
Metals inventory adjustments		5	1	18	58
Selling, general and administrative expenses		(56)	(55)	(130)	(123)
Mining exploration and research expenses		17	30	32	57
Environmental obligations and shutdown costs		11	23	36	65
Net gain on sales of assets			8	11	(25)
Operating income (loss)		(169)	(165)	(312)	(433)
Interest expense, net		92	99	186	209
Provision for (benefit from) income taxes		(28)	7	(22)	(20)
Total assets		2,579	3,911	2,579	3,911
Capital expenditures		9	28	20	51
Intersegment
Segment Reporting Information [Line Items]
Revenues		0	0	0	0
Intersegment | North America
Segment Reporting Information [Line Items]
Revenues		952	1,035	1,928	1,962
Intersegment | South America
Segment Reporting Information [Line Items]
Revenues		52	71	90	197
PT Smelting | Affiliated Entity [Member]
Segment Reporting Information [Line Items]
Revenues		433	470	813		$ 879
Morenci [Member] | Operating Segments | North America
Segment Reporting Information [Line Items]
Revenues		20	16	22	28
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization (Deprecated 2019-01-31)		(348)	(348)	(697)	(643)
Cost, Depreciation, Amortization and Depletion		43	43	87	83
Metals inventory adjustments		0	0	4	0
Selling, general and administrative expenses		0	0	(1)	(1)
Mining exploration and research expenses		0	0	0	0
Environmental obligations and shutdown costs		0	0	0	0
Net gain on sales of assets			0	0	0
Operating income (loss)		76	116	122	250
Interest expense, net		1	1	2	2
Provision for (benefit from) income taxes		0	0	0	0
Total assets		2,697	2,917	2,697	2,917
Capital expenditures		27	49	71	111
Morenci [Member] | Intersegment | North America
Segment Reporting Information [Line Items]
Revenues		447	491	889	949
Bagdad [Member] | Operating Segments | North America
Segment Reporting Information [Line Items]
Revenues		0	0	0	0
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization (Deprecated 2019-01-31)		(118)	(128)	(244)	(248)
Cost, Depreciation, Amortization and Depletion		13	11	27	21
Metals inventory adjustments		0	0	0	0
Selling, general and administrative expenses		0	0	0	0
Mining exploration and research expenses		0	0	0	0
Environmental obligations and shutdown costs		0	0	0	0
Net gain on sales of assets			0	0	0
Operating income (loss)		35	65	54	113
Interest expense, net		0	0		0
Provision for (benefit from) income taxes		0	0	0	0
Total assets		794	742	794	742
Capital expenditures		12	33	37	58
Bagdad [Member] | Operating Segments | Bagdad [Member]
Segment Reporting Information [Line Items]
Interest expense, net				0
Bagdad [Member] | Intersegment | North America
Segment Reporting Information [Line Items]
Revenues		166	204	325	382
Other Mines North America Copper Mines Segment [Member] | Operating Segments | North America
Segment Reporting Information [Line Items]
Metals inventory adjustments			1		1
Other Individually Immaterial Operating Segments [Member] | Operating Segments | North America
Segment Reporting Information [Line Items]
Revenues		16	69	23	164
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization (Deprecated 2019-01-31)		(321)	(348)	(706)	(676)
Cost, Depreciation, Amortization and Depletion		33	33	67	66
Metals inventory adjustments		(89)		52
Selling, general and administrative expenses		(1)	0	(1)	(1)
Mining exploration and research expenses		1	1	2	1
Environmental obligations and shutdown costs		0	0	0	0
Net gain on sales of assets			0	0	0
Operating income (loss)		88	26	(91)	50
Interest expense, net		0	0	0	0
Provision for (benefit from) income taxes		0	0	0	0
Total assets		4,404	4,179	4,404	4,179
Capital expenditures		109	125	224	248
Other Individually Immaterial Operating Segments [Member] | Operating Segments | South America
Segment Reporting Information [Line Items]
Revenues		106	128	204	226
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization (Deprecated 2019-01-31)		(104)	(126)	(214)	(226)
Cost, Depreciation, Amortization and Depletion		14	18	29	32
Metals inventory adjustments		(57)	0	3	0
Selling, general and administrative expenses		0	0	0	0
Mining exploration and research expenses		0	0	0	0
Environmental obligations and shutdown costs		0	0	0	0
Net gain on sales of assets			0	0	0
Operating income (loss)		45	(16)	(42)	(32)
Interest expense, net		0	0	0	0
Provision for (benefit from) income taxes		16	(9)	(10)	(14)
Total assets		1,631	1,699	1,631	1,699
Capital expenditures		20	4	35	9
Other Individually Immaterial Operating Segments [Member] | Intersegment | North America
Segment Reporting Information [Line Items]
Revenues		339	340	714	631
Other Individually Immaterial Operating Segments [Member] | Intersegment | South America
Segment Reporting Information [Line Items]
Revenues		0	0	0	0
Cerro Verde [Member] | Operating Segments | South America
Segment Reporting Information [Line Items]
Revenues		471	562	847	1,289
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization (Deprecated 2019-01-31)		(334)	(455)	(758)	(894)
Cost, Depreciation, Amortization and Depletion		88	101	181	201
Metals inventory adjustments		0	0	0	0
Selling, general and administrative expenses		(1)	(2)	(3)	(4)
Mining exploration and research expenses		0	0	0	0
Environmental obligations and shutdown costs		0	0	0	0
Net gain on sales of assets			0	0	0
Operating income (loss)		100	75	(5)	387
Interest expense, net		20	25	48	54
Provision for (benefit from) income taxes		29	20	(23)	130
Total assets		8,515	8,571	8,515	8,571
Capital expenditures		31	43	90	99
Cerro Verde [Member] | Intersegment | South America
Segment Reporting Information [Line Items]
Revenues		52	71	90	197
Grasberg Segment [Member]
Segment Reporting Information [Line Items]
Capital expenditures				634	658
Grasberg Segment [Member] | Operating Segments | Indonesia
Segment Reporting Information [Line Items]
Revenues		683	583	1,128	1,288
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization (Deprecated 2019-01-31)		(378)	(554)	(721)	(1,110)
Cost, Depreciation, Amortization and Depletion		124	99	225	204
Metals inventory adjustments		0	0	0	0
Selling, general and administrative expenses		(28)	(30)	(56)	(60)
Mining exploration and research expenses		0	0	0	0
Environmental obligations and shutdown costs		0	0	0	0
Net gain on sales of assets			0	0	0
Operating income (loss)		188	(101)	161	(29)
Interest expense, net		1	1	2	1
Provision for (benefit from) income taxes		78	(35)	90	(9)
Total assets		16,848	16,261	16,848	16,261
Capital expenditures		308	339	634	658
Grasberg Segment [Member] | Intersegment | Indonesia
Segment Reporting Information [Line Items]
Revenues		35	(1)	35	57
Molybdenum
Segment Reporting Information [Line Items]
Capital expenditures				11	6
Molybdenum | Operating Segments
Segment Reporting Information [Line Items]
Revenues		0	0	0	0
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization (Deprecated 2019-01-31)		(61)	(78)	(127)	(149)
Cost, Depreciation, Amortization and Depletion		15	18	31	34
Metals inventory adjustments		1	0	5	0
Selling, general and administrative expenses		0	0	0	0
Mining exploration and research expenses		0	0	0	0
Environmental obligations and shutdown costs		0	0	0	0
Net gain on sales of assets			0	0	0
Operating income (loss)		(19)	13	(34)	17
Interest expense, net		0	0	0	0
Provision for (benefit from) income taxes		0	0	0	0
Total assets		1,777	1,792	1,777	1,792
Capital expenditures		4	2	11	6
Molybdenum | Intersegment
Segment Reporting Information [Line Items]
Revenues		58	109	129	200
Rod and Refining Segment [Member] | Operating Segments
Segment Reporting Information [Line Items]
Revenues		1,106	1,171	2,221	2,299
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization (Deprecated 2019-01-31)		(1,138)	(1,171)	(2,257)	(2,304)
Cost, Depreciation, Amortization and Depletion		6	3	8	5
Metals inventory adjustments		1	0	1	0
Selling, general and administrative expenses		0	0	0	0
Mining exploration and research expenses		0	0	0	0
Environmental obligations and shutdown costs		0	0	1	0
Net gain on sales of assets			0	0	0
Operating income (loss)		(31)	1	(30)	0
Interest expense, net		0	0	0	0
Provision for (benefit from) income taxes		0	0	0	0
Total assets		259	250	259	250
Capital expenditures		2	1	4	2
Rod and Refining Segment [Member] | Intersegment
Segment Reporting Information [Line Items]
Revenues		8	4	16	10
Atlantic Copper Smelting and Refining Segment [Member] | Operating Segments
Segment Reporting Information [Line Items]
Revenues		464	546	893	1,117
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization (Deprecated 2019-01-31)		(446)	(515)	(857)	(1,067)
Cost, Depreciation, Amortization and Depletion		7	7	14	14
Metals inventory adjustments		0	0	0	0
Selling, general and administrative expenses		(5)	(5)	(10)	(10)
Mining exploration and research expenses		0	0	0	0
Environmental obligations and shutdown costs		0	0	0	0
Net gain on sales of assets			0	0	0
Operating income (loss)		8	19	25	31
Interest expense, net		1	6	4	12
Provision for (benefit from) income taxes		1	2	1	3
Total assets		726	764	726	764
Capital expenditures		5	5	11	9
Atlantic Copper Smelting and Refining Segment [Member] | Intersegment
Segment Reporting Information [Line Items]
Revenues		2	0	13	5
Corporate And Eliminations | Intersegment
Segment Reporting Information [Line Items]
Revenues		(1,107)	$ (1,218)	(2,211)	$ (2,431)
Forward Contracts [Member] | Designated as Hedging Instrument [Member]
Segment Reporting Information [Line Items]
Matured derivative financial instruments		$ 24		$ 24
Derivative, Nonmonetary Notional Amount, Mass | lb	150
Derivative, Average Forward Price | $ / lb	2.34