Business Segments (Segment Reporting) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2020 USD ($) segment	Mar. 31, 2019 USD ($)	Dec. 31, 2019 USD ($)
Segment Reporting Information [Line Items]
Number of Operating Segments | segment	4
Deferred Intercompany Profit, Percentage	25.00%
Revenues	$ 2,798	$ 3,792
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization (Deprecated 2019-01-31)	(2,545)	(2,919)
Cost, Depreciation, Amortization and Depletion	341	347
Metals inventory adjustments	222	57
Selling, general and administrative expenses	(110)	(112)
Mining exploration and research expenses	16	27
Environmental obligations and shutdown costs	26	42
Net gain on sales of assets	11	(33)
Operating (loss) income	(473)	321
Interest expense, net	127	146
Provision for (benefit from) income taxes	(60)	105
Total assets	40,219	41,059	$ 40,809
Capital expenditures	610	622
Operating Segments | North America
Segment Reporting Information [Line Items]
Revenues	9	107
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization (Deprecated 2019-01-31)	(860)	(743)
Cost, Depreciation, Amortization and Depletion	92	83
Metals inventory adjustments	145	0
Selling, general and administrative expenses	(1)	(2)
Mining exploration and research expenses	1	0
Environmental obligations and shutdown costs	0	0
Net gain on sales of assets	0	0
Operating (loss) income	(114)	206
Interest expense, net	1	1
Provision for (benefit from) income taxes	0	0
Total assets	7,907	7,664
Capital expenditures	184	210
Operating Segments | South America
Segment Reporting Information [Line Items]
Revenues	474	825
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization (Deprecated 2019-01-31)	(534)	(539)
Cost, Depreciation, Amortization and Depletion	108	114
Metals inventory adjustments	60	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 (loss) income	(192)	296
Interest expense, net	28	29
Provision for (benefit from) income taxes	(78)	105
Total assets	10,126	10,394
Capital expenditures	74	61
Corporate And Eliminations
Segment Reporting Information [Line Items]
Revenues	326	456
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization (Deprecated 2019-01-31)	788	675
Cost, Depreciation, Amortization and Depletion	15	20
Metals inventory adjustments	13	57
Selling, general and administrative expenses	(74)	(73)
Mining exploration and research expenses	15	27
Environmental obligations and shutdown costs	25	42
Net gain on sales of assets	11	(33)
Operating (loss) income	(143)	(268)
Interest expense, net	94	110
Provision for (benefit from) income taxes	6	(27)
Total assets	2,821	4,421
Capital expenditures	11	23
Intersegment
Segment Reporting Information [Line Items]
Revenues	0	0
Intersegment | North America
Segment Reporting Information [Line Items]
Revenues	976	927
Intersegment | South America
Segment Reporting Information [Line Items]
Revenues	38	126
PT Smelting | Affiliated Entity [Member]
Segment Reporting Information [Line Items]
Revenues	380	409
Morenci [Member] | Operating Segments | North America
Segment Reporting Information [Line Items]
Revenues	2	12
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization (Deprecated 2019-01-31)	(349)	(295)
Cost, Depreciation, Amortization and Depletion	44	40
Metals inventory adjustments	4	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 (loss) income	46	134
Interest expense, net	1	1
Provision for (benefit from) income taxes	0	0
Total assets	2,814	2,904
Capital expenditures	44	62
Morenci [Member] | Intersegment | North America
Segment Reporting Information [Line Items]
Revenues	442	458
Bagdad [Member] | Operating Segments | North America
Segment Reporting Information [Line Items]
Revenues	0	0
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization (Deprecated 2019-01-31)	(126)	(120)
Cost, Depreciation, Amortization and Depletion	14	10
Metals inventory adjustments	0	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 (loss) income	19	48
Interest expense, net	0	0
Provision for (benefit from) income taxes	0	0
Total assets	800	709
Capital expenditures	25	25
Bagdad [Member] | Intersegment | North America
Segment Reporting Information [Line Items]
Revenues	159	178
Other Mines North America Copper Mines Segment [Member] | Operating Segments | North America
Segment Reporting Information [Line Items]
Metals inventory adjustments		0
Other Individually Immaterial Operating Segments [Member] | Operating Segments | North America
Segment Reporting Information [Line Items]
Revenues	7	95
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization (Deprecated 2019-01-31)	(385)	(328)
Cost, Depreciation, Amortization and Depletion	34	33
Metals inventory adjustments	141
Selling, general and administrative expenses	0	(1)
Mining exploration and research expenses	1	0
Environmental obligations and shutdown costs	0	0
Net gain on sales of assets	0	0
Operating (loss) income	(179)	24
Interest expense, net	0	0
Provision for (benefit from) income taxes	0	0
Total assets	4,293	4,051
Capital expenditures	115	123
Other Individually Immaterial Operating Segments [Member] | Operating Segments | South America
Segment Reporting Information [Line Items]
Revenues	98	98
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization (Deprecated 2019-01-31)	(110)	(100)
Cost, Depreciation, Amortization and Depletion	15	14
Metals inventory adjustments	60	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 (loss) income	(87)	(16)
Interest expense, net	0	0
Provision for (benefit from) income taxes	(26)	(5)
Total assets	1,655	1,720
Capital expenditures	15	5
Other Individually Immaterial Operating Segments [Member] | Intersegment | North America
Segment Reporting Information [Line Items]
Revenues	375	291
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	376	727
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization (Deprecated 2019-01-31)	(424)	(439)
Cost, Depreciation, Amortization and Depletion	93	100
Metals inventory adjustments	0	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 (loss) income	(105)	312
Interest expense, net	28	29
Provision for (benefit from) income taxes	(52)	110
Total assets	8,471	8,674
Capital expenditures	59	56
Cerro Verde [Member] | Intersegment | South America
Segment Reporting Information [Line Items]
Revenues	38	126
Grasberg Segment [Member]
Segment Reporting Information [Line Items]
Capital expenditures	326	319
Grasberg Segment [Member] | Operating Segments | Indonesia
Segment Reporting Information [Line Items]
Revenues	445	705
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization (Deprecated 2019-01-31)	(343)	(556)
Cost, Depreciation, Amortization and Depletion	101	105
Metals inventory adjustments	0	0
Selling, general and administrative expenses	(28)	(30)
Mining exploration and research expenses	0	0
Environmental obligations and shutdown costs	0	0
Net gain on sales of assets	0	0
Operating (loss) income	(27)	72
Interest expense, net	1	0
Provision for (benefit from) income taxes	12	26
Total assets	16,711	15,792
Capital expenditures	326	319
Grasberg Segment [Member] | Intersegment | Indonesia
Segment Reporting Information [Line Items]
Revenues	0	58
Molybdenum
Segment Reporting Information [Line Items]
Capital expenditures	7	4
Molybdenum | Operating Segments
Segment Reporting Information [Line Items]
Revenues	0	0
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization (Deprecated 2019-01-31)	(66)	(71)
Cost, Depreciation, Amortization and Depletion	16	16
Metals inventory adjustments	4	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 (loss) income	(15)	4
Interest expense, net	0	0
Provision for (benefit from) income taxes	0	0
Total assets	1,788	1,785
Capital expenditures	7	4
Molybdenum | Intersegment
Segment Reporting Information [Line Items]
Revenues	71	91
Rod and Refining Segment [Member] | Operating Segments
Segment Reporting Information [Line Items]
Revenues	1,115	1,128
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization (Deprecated 2019-01-31)	(1,119)	(1,133)
Cost, Depreciation, Amortization and Depletion	2	2
Metals inventory adjustments	0	0
Selling, general and administrative expenses	0	0
Mining exploration and research expenses	0	0
Environmental obligations and shutdown costs	1	0
Net gain on sales of assets	0	0
Operating (loss) income	1	(1)
Interest expense, net	0	0
Provision for (benefit from) income taxes	0	0
Total assets	231	232
Capital expenditures	2	1
Rod and Refining Segment [Member] | Intersegment
Segment Reporting Information [Line Items]
Revenues	8	6
Atlantic Copper Smelting and Refining Segment [Member] | Operating Segments
Segment Reporting Information [Line Items]
Revenues	429	571
Cost of Goods Sold, Excluding Depreciation, Depletion, and Amortization (Deprecated 2019-01-31)	(411)	(552)
Cost, Depreciation, Amortization and Depletion	7	7
Metals inventory adjustments	0	0
Selling, general and administrative expenses	(5)	(5)
Mining exploration and research expenses	0	0
Environmental obligations and shutdown costs	0	0
Net gain on sales of assets	0	0
Operating (loss) income	17	12
Interest expense, net	3	6
Provision for (benefit from) income taxes	0	1
Total assets	635	771
Capital expenditures	6	4
Atlantic Copper Smelting and Refining Segment [Member] | Intersegment
Segment Reporting Information [Line Items]
Revenues	11	5
Corporate And Eliminations | Intersegment
Segment Reporting Information [Line Items]
Revenues	$ (1,104)	$ (1,213)