Business Segments (Segment Reporting) (Details) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($) segment	Sep. 30, 2018 USD ($)	Dec. 31, 2018 USD ($)
Segment Reporting Information [Line Items]
Number of Operating Segments | segment			4
Deferred Intercompany Profit, Percentage			25.00%
Revenues	$ 3,153	$ 4,908	$ 10,491	$ 14,944
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization (Deprecated 2019-01-31)	(2,665)	(3,069)	(8,584)	(8,790)
Cost, Depreciation, Amortization and Depletion	322	458	1,021	1,351
Metals inventory adjustments	41	0	100	2
Selling, general and administrative expenses	(106)	(101)	(315)	(341)
Mining exploration and research expenses	25	27	83	72
Environmental obligations and shutdown costs	20	8	85	76
Net gain on sales of assets	12	(70)	(13)	(126)
Operating (loss) income	(38)	1,315	316	4,438
Interest expense, net	(123)	(143)	(401)	(436)
Provision for (benefit from) income taxes	91	522	181	1,543
Total assets	40,943	37,749	40,943	37,749	$ 42,216
Capital expenditures	666	507	1,917	1,391
Operating Segments | North America
Segment Reporting Information [Line Items]
Revenues	80	32	272	88
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization (Deprecated 2019-01-31)	(896)	(789)	(2,463)	(2,367)
Cost, Depreciation, Amortization and Depletion	91	88	261	274
Metals inventory adjustments	38		39	2
Selling, general and administrative expenses	(2)	(1)	(4)	(5)
Mining exploration and research expenses	0	1	1	2
Environmental obligations and shutdown costs	0	2	0	2
Net gain on sales of assets	0	0	0	0
Operating (loss) income	113	205	526	989
Interest expense, net	(1)	(1)	(3)	(3)
Provision for (benefit from) income taxes	0	0	0	0
Total assets	7,948	7,291	7,948	7,291
Capital expenditures	224	181	641	413
Operating Segments | South America
Segment Reporting Information [Line Items]
Revenues	621	809	2,136	2,474
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization (Deprecated 2019-01-31)	(528)	(624)	(1,648)	(1,745)
Cost, Depreciation, Amortization and Depletion	109	142	342	402
Metals inventory adjustments	2		2	0
Selling, general and administrative expenses	(2)	(3)	(6)	(7)
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	0
Operating (loss) income	45	111	400	593
Interest expense, net	(25)	(15)	(79)	(48)
Provision for (benefit from) income taxes	33	42	149	222
Total assets	10,223	10,322	10,223	10,322
Capital expenditures	68	50	176	188
Corporate And Eliminations
Segment Reporting Information [Line Items]
Revenues	423	573	1,350	1,777
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization (Deprecated 2019-01-31)	775	716	2,173	2,626
Cost, Depreciation, Amortization and Depletion	20	18	59	53
Metals inventory adjustments	0		58	0
Selling, general and administrative expenses	(66)	(63)	(199)	(217)
Mining exploration and research expenses	25	26	82	70
Environmental obligations and shutdown costs	20	6	85	74
Net gain on sales of assets	12	(70)	(13)	(126)
Operating (loss) income	(168)	(49)	(601)	(158)
Interest expense, net	(91)	(120)	(300)	(367)
Provision for (benefit from) income taxes	67	56	39	66
Total assets	3,623	5,445	3,623	5,445
Capital expenditures	25	22	76	76
Intersegment
Segment Reporting Information [Line Items]
Revenues	0	0	0	0
Intersegment | North America
Segment Reporting Information [Line Items]
Revenues	1,060	1,054	3,022	3,553
Intersegment | South America
Segment Reporting Information [Line Items]
Revenues	65	71	262	273
PT Smelting | Affiliated Entity [Member]
Segment Reporting Information [Line Items]
Revenues	475	827	1,400	2,100
Morenci [Member] | Operating Segments | North America
Segment Reporting Information [Line Items]
Revenues	61	30	89	58
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization (Deprecated 2019-01-31)	(377)	(304)	(1,020)	(892)
Cost, Depreciation, Amortization and Depletion	45	43	128	133
Metals inventory adjustments	1		1	0
Selling, general and administrative expenses	(1)	(1)	(2)	(3)
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	0
Operating (loss) income	99	149	349	666
Interest expense, net	0	(1)	(2)	(3)
Provision for (benefit from) income taxes	0	0	0	0
Total assets	2,943	2,826	2,943	2,826
Capital expenditures	61	63	172	151
Morenci [Member] | Intersegment | North America
Segment Reporting Information [Line Items]
Revenues	462	467	1,411	1,636
Other Individually Immaterial Operating Segments [Member] | Operating Segments | North America
Segment Reporting Information [Line Items]
Revenues	19	2	183	30
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization (Deprecated 2019-01-31)	(519)	(485)	(1,443)	(1,475)
Cost, Depreciation, Amortization and Depletion	46	45	133	141
Metals inventory adjustments	37		38	2
Selling, general and administrative expenses	(1)	0	(2)	(2)
Mining exploration and research expenses	0	1	1	2
Environmental obligations and shutdown costs	0	2	0	2
Net gain on sales of assets	0	0	0	0
Operating (loss) income	14	56	177	323
Interest expense, net	(1)	0	(1)	0
Provision for (benefit from) income taxes	0	0	0	0
Total assets	5,005	4,465	5,005	4,465
Capital expenditures	163	118	469	262
Other Individually Immaterial Operating Segments [Member] | Operating Segments | South America
Segment Reporting Information [Line Items]
Revenues	117	122	343	443
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization (Deprecated 2019-01-31)	(111)	(105)	(337)	(354)
Cost, Depreciation, Amortization and Depletion	16	20	48	66
Metals inventory adjustments	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	0
Operating (loss) income	(10)	(3)	(42)	23
Interest expense, net	0	0	0	0
Provision for (benefit from) income taxes	4	5	(10)	15
Total assets	1,723	1,709	1,723	1,709
Capital expenditures	7	3	16	10
Other Individually Immaterial Operating Segments [Member] | Intersegment | North America
Segment Reporting Information [Line Items]
Revenues	598	587	1,611	1,917
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	504	687	1,793	2,031
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization (Deprecated 2019-01-31)	(417)	(519)	(1,311)	(1,391)
Cost, Depreciation, Amortization and Depletion	93	122	294	336
Metals inventory adjustments	2		2	0
Selling, general and administrative expenses	(2)	(3)	(6)	(7)
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	0
Operating (loss) income	55	114	442	570
Interest expense, net	(25)	(15)	(79)	(48)
Provision for (benefit from) income taxes	29	37	159	207
Total assets	8,500	8,613	8,500	8,613
Capital expenditures	61	47	160	178
Cerro Verde [Member] | Intersegment | South America
Segment Reporting Information [Line Items]
Revenues	65	71	262	273
Grasberg Segment [Member]
Segment Reporting Information [Line Items]
Capital expenditures			992	695
Grasberg Segment [Member] | Operating Segments | Indonesia
Segment Reporting Information [Line Items]
Revenues	488	1,703	1,776	4,863
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization (Deprecated 2019-01-31)	(399)	(522)	(1,509)	(1,404)
Cost, Depreciation, Amortization and Depletion	77	181	281	534
Metals inventory adjustments	0		0	0
Selling, general and administrative expenses	(31)	(29)	(91)	(96)
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	0
Operating (loss) income	(19)	1,032	(48)	2,943
Interest expense, net	(1)	0	(2)	0
Provision for (benefit from) income taxes	(8)	424	(9)	1,254
Total assets	16,447	11,764	16,447	11,764
Capital expenditures	334	246	992	695
Grasberg Segment [Member] | Intersegment | Indonesia
Segment Reporting Information [Line Items]
Revenues	0	61	57	114
Molybdenum [Member]
Segment Reporting Information [Line Items]
Capital expenditures			11	6
Molybdenum [Member] | 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)	(85)	(76)	(234)	(214)
Cost, Depreciation, Amortization and Depletion	16	20	50	60
Metals inventory adjustments	1		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	0	0
Net gain on sales of assets	0	0	0	0
Operating (loss) income	(12)	5	5	33
Interest expense, net	0	0	0	0
Provision for (benefit from) income taxes	0	0	0	0
Total assets	1,786	1,808	1,786	1,808
Capital expenditures	5	4	11	6
Molybdenum [Member] | Intersegment
Segment Reporting Information [Line Items]
Revenues	90	101	290	307
Rod and Refining Segment [Member] | Operating Segments
Segment Reporting Information [Line Items]
Revenues	1,104	1,212	3,403	3,984
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization (Deprecated 2019-01-31)	(1,111)	(1,215)	(3,415)	(3,992)
Cost, Depreciation, Amortization and Depletion	2	3	7	8
Metals inventory adjustments	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	0
Operating (loss) income	(1)	2	(1)	8
Interest expense, net	0	0	0	0
Provision for (benefit from) income taxes	0	0	0	0
Total assets	236	284	236	284
Capital expenditures	1	1	3	3
Rod and Refining Segment [Member] | Intersegment
Segment Reporting Information [Line Items]
Revenues	8	8	18	24
Atlantic Copper Smelting and Refining Segment [Member] | Operating Segments
Segment Reporting Information [Line Items]
Revenues	437	579	1,554	1,758
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization (Deprecated 2019-01-31)	(421)	(559)	(1,488)	(1,694)
Cost, Depreciation, Amortization and Depletion	7	6	21	20
Metals inventory adjustments	0		0	0
Selling, general and administrative expenses	(5)	(5)	(15)	(16)
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	0
Operating (loss) income	4	9	35	30
Interest expense, net	(5)	(7)	(17)	(18)
Provision for (benefit from) income taxes	(1)	0	2	1
Total assets	680	835	680	835
Capital expenditures	9	3	18	10
Atlantic Copper Smelting and Refining Segment [Member] | Intersegment
Segment Reporting Information [Line Items]
Revenues	0	0	5	2
Corporate And Eliminations | Intersegment
Segment Reporting Information [Line Items]
Revenues	$ (1,223)	$ (1,295)	$ (3,654)	$ (4,273)