Business Segments (Segment Reporting) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2019 USD ($) segment	Mar. 31, 2018 USD ($)	Dec. 31, 2018 USD ($)
Segment Reporting Information [Line Items]
Number of Operating Segments | segment	4
Deferred Intercompany Profit, Percentage	25.00%
Revenues	$ 3,792	$ 4,868
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization	(2,919)	(2,808)
Cost, Depreciation, Amortization and Depletion	347	451
Metals inventory adjustments	57	0
Selling, general and administrative expenses	(112)	(131)
Mining exploration and research expenses	27	21
Environmental obligations and shutdown costs	42	9
Net gain on sales of assets	(33)	(11)
Operating income	321	1,459
Interest expense, net	(146)	(151)
Provision for (benefit from) income taxes	105	506
Total assets	41,059	36,637	$ 42,216
Capital expenditures	622	402
Operating Segments | North America
Segment Reporting Information [Line Items]
Revenues	107	18
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization	(743)	(791)
Cost, Depreciation, Amortization and Depletion	83	94
Metals inventory adjustments	0
Selling, general and administrative expenses	(2)	(3)
Mining exploration and research expenses	0	1
Environmental obligations and shutdown costs	0	0
Net gain on sales of assets	0	0
Operating income	206	419
Interest expense, net	(1)	(1)
Provision for (benefit from) income taxes	0	0
Total assets	7,664	7,157
Capital expenditures	210	92
Operating Segments | South America
Segment Reporting Information [Line Items]
Revenues	825	775
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization	(539)	(543)
Cost, Depreciation, Amortization and Depletion	114	127
Metals inventory adjustments	0
Selling, general and administrative expenses	(2)	(2)
Mining exploration and research expenses	0	0
Environmental obligations and shutdown costs	0	0
Net gain on sales of assets	0	0
Operating income	296	205
Interest expense, net	(29)	(17)
Provision for (benefit from) income taxes	105	72
Total assets	10,394	10,455
Capital expenditures	61	67
Corporate And Eliminations
Segment Reporting Information [Line Items]
Revenues	456	592
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization	675	994
Cost, Depreciation, Amortization and Depletion	20	21
Metals inventory adjustments	57
Selling, general and administrative expenses	(73)	(81)
Mining exploration and research expenses	27	20
Environmental obligations and shutdown costs	42	9
Net gain on sales of assets	(33)	(11)
Operating income	(268)	(83)
Interest expense, net	(110)	(128)
Provision for (benefit from) income taxes	(27)	32
Total assets	4,421	5,098
Capital expenditures	23	34
Intersegment
Segment Reporting Information [Line Items]
Revenues	0	0
Intersegment | North America
Segment Reporting Information [Line Items]
Revenues	927	1,290
Intersegment | South America
Segment Reporting Information [Line Items]
Revenues	126	102
Pt Smelting | Affiliated Entity [Member]
Segment Reporting Information [Line Items]
Revenues	409	628
Morenci [Member] | Operating Segments | North America
Segment Reporting Information [Line Items]
Revenues	12	3
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization	(295)	(290)
Cost, Depreciation, Amortization and Depletion	40	46
Metals inventory adjustments	0
Selling, general and administrative expenses	(1)	(1)
Mining exploration and research expenses	0	0
Environmental obligations and shutdown costs	0	0
Net gain on sales of assets	0	0
Operating income	134	267
Interest expense, net	(1)	(1)
Provision for (benefit from) income taxes	0	0
Total assets	2,904	2,817
Capital expenditures	62	47
Morenci [Member] | Intersegment | North America
Segment Reporting Information [Line Items]
Revenues	458	601
Other Individually Immaterial Operating Segments [Member] | Operating Segments | North America
Segment Reporting Information [Line Items]
Revenues	95	15
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization	(448)	(501)
Cost, Depreciation, Amortization and Depletion	43	48
Metals inventory adjustments	0
Selling, general and administrative expenses	(1)	(2)
Mining exploration and research expenses	0	1
Environmental obligations and shutdown costs	0	0
Net gain on sales of assets	0	0
Operating income	72	152
Interest expense, net	0	0
Provision for (benefit from) income taxes	0	0
Total assets	4,760	4,340
Capital expenditures	148	45
Other Individually Immaterial Operating Segments [Member] | Operating Segments | South America
Segment Reporting Information [Line Items]
Revenues	98	150
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization	(100)	(116)
Cost, Depreciation, Amortization and Depletion	14	22
Metals inventory adjustments	0
Selling, general and administrative expenses	0	0
Mining exploration and research expenses	0	0
Environmental obligations and shutdown costs	0	0
Net gain on sales of assets	0	0
Operating income	(16)	12
Interest expense, net	0	0
Provision for (benefit from) income taxes	(5)	4
Total assets	1,720	1,715
Capital expenditures	5	4
Other Individually Immaterial Operating Segments [Member] | Intersegment | North America
Segment Reporting Information [Line Items]
Revenues	469	689
Other Individually Immaterial Operating Segments [Member] | Intersegment | South America
Segment Reporting Information [Line Items]
Revenues	0	0
Cerro Verde [Member] | Operating Segments | South America
Segment Reporting Information [Line Items]
Revenues	727	625
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization	(439)	(427)
Cost, Depreciation, Amortization and Depletion	100	105
Metals inventory adjustments	0
Selling, general and administrative expenses	(2)	(2)
Mining exploration and research expenses	0	0
Environmental obligations and shutdown costs	0	0
Net gain on sales of assets	0	0
Operating income	312	193
Interest expense, net	(29)	(17)
Provision for (benefit from) income taxes	110	68
Total assets	8,674	8,740
Capital expenditures	56	63
Cerro Verde [Member] | Intersegment | South America
Segment Reporting Information [Line Items]
Revenues	126	102
Grasberg Segment [Member]
Segment Reporting Information [Line Items]
Capital expenditures	319	203
Grasberg Segment [Member] | Operating Segments | Indonesia
Segment Reporting Information [Line Items]
Revenues	705	1,521
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization	(556)	(457)
Cost, Depreciation, Amortization and Depletion	105	181
Metals inventory adjustments	0
Selling, general and administrative expenses	(30)	(39)
Mining exploration and research expenses	0	0
Environmental obligations and shutdown costs	0	0
Net gain on sales of assets	0	0
Operating income	72	896
Interest expense, net	0	0
Provision for (benefit from) income taxes	26	401
Total assets	15,792	10,992
Capital expenditures	319	203
Grasberg Segment [Member] | Intersegment | Indonesia
Segment Reporting Information [Line Items]
Revenues	58	52
Molybdenum [Member]
Segment Reporting Information [Line Items]
Capital expenditures	4	1
Molybdenum [Member] | Operating Segments
Segment Reporting Information [Line Items]
Revenues	0	0
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization	(71)	(67)
Cost, Depreciation, Amortization and Depletion	16	19
Metals inventory adjustments	0
Selling, general and administrative expenses	0	0
Mining exploration and research expenses	0	0
Environmental obligations and shutdown costs	0	0
Net gain on sales of assets	0	0
Operating income	4	9
Interest expense, net	0	0
Provision for (benefit from) income taxes	0	0
Total assets	1,785	1,836
Capital expenditures	4	1
Molybdenum [Member] | Intersegment
Segment Reporting Information [Line Items]
Revenues	91	95
Rod and Refining Segment [Member] | Operating Segments
Segment Reporting Information [Line Items]
Revenues	1,128	1,385
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization	(1,133)	(1,388)
Cost, Depreciation, Amortization and Depletion	2	2
Metals inventory adjustments	0
Selling, general and administrative expenses	0	0
Mining exploration and research expenses	0	0
Environmental obligations and shutdown costs	0	0
Net gain on sales of assets	0	0
Operating income	(1)	3
Interest expense, net	0	0
Provision for (benefit from) income taxes	0	0
Total assets	232	290
Capital expenditures	1	1
Rod and Refining Segment [Member] | Intersegment
Segment Reporting Information [Line Items]
Revenues	6	8
Atlantic Copper Smelting and Refining Segment [Member] | Operating Segments
Segment Reporting Information [Line Items]
Revenues	571	577
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization	(552)	(556)
Cost, Depreciation, Amortization and Depletion	7	7
Metals inventory adjustments	0
Selling, general and administrative expenses	(5)	(6)
Mining exploration and research expenses	0	0
Environmental obligations and shutdown costs	0	0
Net gain on sales of assets	0	0
Operating income	12	10
Interest expense, net	(6)	(5)
Provision for (benefit from) income taxes	1	1
Total assets	771	809
Capital expenditures	4	4
Atlantic Copper Smelting and Refining Segment [Member] | Intersegment
Segment Reporting Information [Line Items]
Revenues	5	2
Corporate And Eliminations | Intersegment
Segment Reporting Information [Line Items]
Revenues	$ (1,213)	$ (1,549)