Business Segments (Segment Reporting) (Details) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2018 USD ($) segment	Sep. 30, 2017 USD ($)	Dec. 31, 2017 USD ($)
Segment Reporting Information [Line Items]
Number of Operating Segments | segment			4
Deferred Intercompany Profit, Percentage			25.00%
Revenues	$ 4,908	$ 4,310	$ 14,944	$ 11,362
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization	(3,069)	(2,794)	(8,792)	(7,462)
Cost, Depreciation, Amortization and Depletion	458	418	1,351	1,257
Selling, general and administrative expenses	(101)	(104)	(341)	(362)
Mining exploration and research expenses	27	27	72	60
Environmental obligations and shutdown costs	8	72	76	76
Net gain on sales of assets	(70)	(33)	(126)	(66)
Operating income	1,315	928	4,438	2,211
Interest expense, net	(143)	(304)	(436)	(633)
Provision for (benefit from) income taxes	522	387	1,543	747
Total assets	37,749	37,327	37,749	37,327	$ 37,302
Capital expenditures	507	314	1,391	1,020
Assets held for sale	626	459	626	459	$ 508
Operating Segments | North America
Segment Reporting Information [Line Items]
Revenues	32	97	88	290
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization	(789)	(652)	(2,369)	(2,038)
Cost, Depreciation, Amortization and Depletion	88	96	274	330
Selling, general and administrative expenses	(1)	(2)	(5)	(4)
Mining exploration and research expenses	1	0	2	2
Environmental obligations and shutdown costs	2	0	2	0
Net gain on sales of assets	0	0	0	0
Operating income	205	355	989	974
Interest expense, net	(1)	(1)	(3)	(3)
Provision for (benefit from) income taxes	0	0	0	0
Total assets	7,291	7,067	7,291	7,067
Capital expenditures	181	39	413	106
Operating Segments | South America
Segment Reporting Information [Line Items]
Revenues	809	959	2,474	2,389
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization	(624)	(759)	(1,745)	(1,695)
Cost, Depreciation, Amortization and Depletion	142	134	402	392
Selling, general and administrative expenses	(3)	(2)	(7)	(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 income	111	128	593	532
Interest expense, net	(15)	(156)	(48)	(187)
Provision for (benefit from) income taxes	42	139	222	298
Total assets	10,322	10,446	10,322	10,446
Capital expenditures	50	20	188	65
Corporate And Eliminations
Segment Reporting Information [Line Items]
Revenues	573	442	1,777	1,261
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization	716	754	2,626	2,327
Cost, Depreciation, Amortization and Depletion	18	23	53	77
Selling, general and administrative expenses	(63)	(64)	(217)	(246)
Mining exploration and research expenses	26	27	70	58
Environmental obligations and shutdown costs	6	72	74	76
Net gain on sales of assets	(70)	(33)	(126)	(66)
Operating income	(49)	(103)	(158)	(320)
Interest expense, net	(120)	(141)	(367)	(429)
Provision for (benefit from) income taxes	56	14	66	10
Total assets	5,445	5,814	5,445	5,814
Capital expenditures	22	41	76	149
Intersegment
Segment Reporting Information [Line Items]
Revenues	0	0	0	0
Intersegment | North America
Segment Reporting Information [Line Items]
Revenues	1,054	1,008	3,553	3,058
Intersegment | South America
Segment Reporting Information [Line Items]
Revenues	71	64	273	237
Pt Smelting [Member] | Affiliated Entity [Member]
Segment Reporting Information [Line Items]
Revenues	827	652	2,100	1,400
Morenci [Member] | Operating Segments | North America
Segment Reporting Information [Line Items]
Revenues	30	57	58	168
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization	(304)	(242)	(892)	(765)
Cost, Depreciation, Amortization and Depletion	43	42	133	138
Selling, general and administrative expenses	(1)	(1)	(3)	(2)
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 income	149	232	666	617
Interest expense, net	(1)	(1)	(3)	(2)
Provision for (benefit from) income taxes	0	0	0	0
Total assets	2,826	2,844	2,826	2,844
Capital expenditures	63	26	151	78
Morenci [Member] | Intersegment | North America
Segment Reporting Information [Line Items]
Revenues	467	460	1,636	1,354
Other Individually Immaterial Operating Segments [Member] | Operating Segments | North America
Segment Reporting Information [Line Items]
Revenues	2	40	30	122
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization	(485)	(410)	(1,477)	(1,273)
Cost, Depreciation, Amortization and Depletion	45	54	141	192
Selling, general and administrative expenses	0	(1)	(2)	(2)
Mining exploration and research expenses	1	0	2	2
Environmental obligations and shutdown costs	2	0	2	0
Net gain on sales of assets	0	0	0	0
Operating income	56	123	323	357
Interest expense, net	0	0	0	(1)
Provision for (benefit from) income taxes	0	0	0	0
Total assets	4,465	4,223	4,465	4,223
Capital expenditures	118	13	262	28
Other Individually Immaterial Operating Segments [Member] | Operating Segments | South America
Segment Reporting Information [Line Items]
Revenues	122	109	443	332
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization	(105)	(76)	(354)	(245)
Cost, Depreciation, Amortization and Depletion	20	18	66	60
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 income	(3)	15	23	27
Interest expense, net	0	0	0	0
Provision for (benefit from) income taxes	5	5	15	10
Total assets	1,709	1,595	1,709	1,595
Capital expenditures	3	3	10	5
Other Individually Immaterial Operating Segments [Member] | Intersegment | North America
Segment Reporting Information [Line Items]
Revenues	587	548	1,917	1,704
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	687	850	2,031	2,057
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization	(519)	(683)	(1,391)	(1,450)
Cost, Depreciation, Amortization and Depletion	122	116	336	332
Selling, general and administrative expenses	(3)	(2)	(7)	(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 income	114	113	570	505
Interest expense, net	(15)	(156)	(48)	(187)
Provision for (benefit from) income taxes	37	134	207	288
Total assets	8,613	8,851	8,613	8,851
Capital expenditures	47	17	178	60
Cerro Verde [Member] | Intersegment | South America
Segment Reporting Information [Line Items]
Revenues	71	64	273	237
Grasberg Segment [Member]
Segment Reporting Information [Line Items]
Capital expenditures			695	663
Grasberg Segment [Member] | Operating Segments | Indonesia
Segment Reporting Information [Line Items]
Revenues	1,703	1,121	4,863	2,720
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization	(522)	(407)	(1,404)	(1,224)
Cost, Depreciation, Amortization and Depletion	181	136	534	372
Selling, general and administrative expenses	(29)	(32)	(96)	(92)
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 income	1,032	546	2,943	1,032
Interest expense, net	0	(1)	0	(1)
Provision for (benefit from) income taxes	424	233	1,254	435
Total assets	11,764	11,100	11,764	11,100
Capital expenditures	246	206	695	663
Grasberg Segment [Member] | Intersegment | Indonesia
Segment Reporting Information [Line Items]
Revenues	61	0	114	0
Molybdenum [Member]
Segment Reporting Information [Line Items]
Capital expenditures			6	4
Molybdenum [Member] | Operating Segments
Segment Reporting Information [Line Items]
Revenues	0	0	0	0
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization	(76)	(57)	(214)	(167)
Cost, Depreciation, Amortization and Depletion	20	20	60	58
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 income	5	(12)	33	(26)
Interest expense, net	0	0	0	0
Provision for (benefit from) income taxes	0	0	0	0
Total assets	1,808	1,885	1,808	1,885
Capital expenditures	4	2	6	4
Molybdenum [Member] | Intersegment
Segment Reporting Information [Line Items]
Revenues	101	65	307	199
Rod and Refining Segment [Member] | Operating Segments
Segment Reporting Information [Line Items]
Revenues	1,212	1,137	3,984	3,290
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization	(1,215)	(1,140)	(3,992)	(3,296)
Cost, Depreciation, Amortization and Depletion	3	2	8	7
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 income	2	3	8	9
Interest expense, net	0	0	0	0
Provision for (benefit from) income taxes	0	0	0	0
Total assets	284	264	284	264
Capital expenditures	1	1	3	3
Rod and Refining Segment [Member] | Intersegment
Segment Reporting Information [Line Items]
Revenues	8	8	24	22
Atlantic Copper Smelting and Refining Segment [Member] | Operating Segments
Segment Reporting Information [Line Items]
Revenues	579	554	1,758	1,412
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization	(559)	(533)	(1,694)	(1,369)
Cost, Depreciation, Amortization and Depletion	6	7	20	21
Selling, general and administrative expenses	(5)	(4)	(16)	(13)
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 income	9	11	30	10
Interest expense, net	(7)	(5)	(18)	(13)
Provision for (benefit from) income taxes	0	1	1	4
Total assets	835	751	835	751
Capital expenditures	3	5	10	30
Atlantic Copper Smelting and Refining Segment [Member] | Intersegment
Segment Reporting Information [Line Items]
Revenues	0	1	2	1
Corporate And Eliminations | Intersegment
Segment Reporting Information [Line Items]
Revenues	(1,295)	(1,146)	(4,273)	(3,517)
One-time Termination Benefits [Member] | Grasberg Segment [Member] | Operating Segments | Indonesia
Segment Reporting Information [Line Items]
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization				(112)
Selling, general and administrative expenses				(5)
Cerro Verde Collective Labor Agreement [Member] | Cerro Verde [Member] | Operating Segments | South America
Segment Reporting Information [Line Items]
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization	(69)		69
Onshore California [Member] | Corporate And Eliminations
Segment Reporting Information [Line Items]
Net gain on sales of assets	(20)		(76)
Gulf of Mexico Shelf and Madden properties [Member] | Corporate And Eliminations
Segment Reporting Information [Line Items]
Net gain on sales of assets		(33)		(49)
Freeport Cobalt [Member] | Corporate And Eliminations
Segment Reporting Information [Line Items]
Net gain on sales of assets	$ (50)		$ (50)
Kisanfu Exploration Project [Member] | Corporate And Eliminations
Segment Reporting Information [Line Items]
Net gain on sales of assets				(13)
Royalty Assessments [Member] | Cerro Verde [Member] | Operating Segments | South America
Segment Reporting Information [Line Items]
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization		(216)		(216)
Interest expense, net		(141)		(141)
Provision for (benefit from) income taxes		2		2
Restatement Adjustment [Member] | Accounting Standards Update 2017-05 [Member]
Segment Reporting Information [Line Items]
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization		8		35
Selling, general and administrative expenses		2		4
Mining exploration and research expenses				(1)
Environmental obligations and shutdown costs		(1)		(5)
Operating income		$ 11		$ 45