Guarantor Financial Statements (Unaudited) Condensed Consolidating Balance Sheets (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017
ASSETS
Current assets, other than assets held-for-sale	$ 10,343	$ 10,689
Property, plant, equipment and mine development costs, net	22,923	22,934
Investments in consolidated subsidiaries	0	0
Other assets	3,762	3,679
Total assets	37,028	37,302	$ 37,043
LIABILITIES AND EQUITY
Current liabilities, other than liabilities held for sale	3,799	5,011
Long-term debt, less current portion	11,123	11,703
Deferred income taxes	3,702	3,649
Environmental and asset retirement obligations, less current portion	3,631	3,631
Investments in consolidated subsidiaries	0	0
Other liabilities	1,931	2,012
Total liabilities	24,186	26,006
Equity:
Stockholders' equity	9,474	7,977
Noncontrolling interests	3,368	3,319
Total equity	12,842	11,296
Total liabilities and equity	37,028	37,302
Eliminations [Member]
ASSETS
Current assets, other than assets held-for-sale	(1,279)	(790)
Property, plant, equipment and mine development costs, net	0	(10)
Investments in consolidated subsidiaries	(19,003)	(19,570)
Other assets	(77)	(491)
Total assets	(20,359)	(20,861)
LIABILITIES AND EQUITY
Current liabilities, other than liabilities held for sale	(1,395)	(938)
Long-term debt, less current portion	(10,211)	(10,270)
Deferred income taxes	0	0
Environmental and asset retirement obligations, less current portion	0	0
Investments in consolidated subsidiaries	(11,225)	(11,250)
Other liabilities	(3,486)	(3,488)
Total liabilities	(26,317)	(25,946)
Equity:
Stockholders' equity	5,383	4,480
Noncontrolling interests	575	605
Total equity	5,958	5,085
Total liabilities and equity	(20,359)	(20,861)
FCX Issuer [Member] | Reportable Legal Entities [Member]
ASSETS
Current assets, other than assets held-for-sale	619	75
Property, plant, equipment and mine development costs, net	19	14
Investments in consolidated subsidiaries	19,003	19,570
Other assets	547	943
Total assets	20,188	20,602
LIABILITIES AND EQUITY
Current liabilities, other than liabilities held for sale	237	1,683
Long-term debt, less current portion	9,594	10,021
Deferred income taxes	727	748
Environmental and asset retirement obligations, less current portion	0	0
Investments in consolidated subsidiaries	0	0
Other liabilities	156	173
Total liabilities	10,714	12,625
Equity:
Stockholders' equity	9,474	7,977
Noncontrolling interests	0	0
Total equity	9,474	7,977
Total liabilities and equity	20,188	20,602
FM O&G LLC Guarantor [Member] | Reportable Legal Entities [Member]
ASSETS
Current assets, other than assets held-for-sale	783	671
Property, plant, equipment and mine development costs, net	4	11
Investments in consolidated subsidiaries	0	0
Other assets	53	48
Total assets	840	730
LIABILITIES AND EQUITY
Current liabilities, other than liabilities held for sale	120	220
Long-term debt, less current portion	6,686	6,512
Deferred income taxes	0	0
Environmental and asset retirement obligations, less current portion	206	201
Investments in consolidated subsidiaries	857	853
Other liabilities	3,339	3,340
Total liabilities	11,208	11,126
Equity:
Stockholders' equity	(10,368)	(10,396)
Noncontrolling interests	0	0
Total equity	(10,368)	(10,396)
Total liabilities and equity	840	730
Non-Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member]
ASSETS
Current assets, other than assets held-for-sale	10,220	10,733
Property, plant, equipment and mine development costs, net	22,900	22,919
Investments in consolidated subsidiaries	0	0
Other assets	3,239	3,179
Total assets	36,359	36,831
LIABILITIES AND EQUITY
Current liabilities, other than liabilities held for sale	4,837	4,046
Long-term debt, less current portion	5,054	5,440
Deferred income taxes	2,975	2,901
Environmental and asset retirement obligations, less current portion	3,425	3,430
Investments in consolidated subsidiaries	10,368	10,397
Other liabilities	1,922	1,987
Total liabilities	28,581	28,201
Equity:
Stockholders' equity	4,985	5,916
Noncontrolling interests	2,793	2,714
Total equity	7,778	8,630
Total liabilities and equity	$ 36,359	$ 36,831