Guarantor Financial Statements (Unaudited) Condensed Consolidating Balance Sheets (Details) - USD ($) $ in Millions	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017
ASSETS
Current assets, other than assets held-for-sale	$ 8,730		$ 10,720
Property, plant, equipment and mine development costs, net	28,841		28,010
Investments in consolidated subsidiaries	0		0
Other assets	3,515		3,486
Total assets	41,086		42,216	$ 37,028
LIABILITIES AND EQUITY
Current liabilities, other than liabilities held for sale	3,286		3,329
Long-term debt, less current portion	9,912		11,124
Deferred income taxes	4,055		4,032
Environmental and asset retirement obligations, less current portion	3,617		3,609
Investments in consolidated subsidiaries	0		0
Other liabilities	2,399		2,230
Total liabilities	23,269		24,324
Equity:
Stockholders' equity	9,709		9,798
Noncontrolling interests	8,108		8,094
Total equity	17,817	$ 17,841	17,892	$ 12,842	$ 11,926	$ 11,296
Total liabilities and equity	41,086		42,216
Eliminations [Member]
ASSETS
Current assets, other than assets held-for-sale	(558)		(585)
Property, plant, equipment and mine development costs, net	0		0
Investments in consolidated subsidiaries	(17,773)		(19,064)
Other assets	(1,093)		(635)
Total assets	(19,424)		(20,284)
LIABILITIES AND EQUITY
Current liabilities, other than liabilities held for sale	(598)		(617)
Long-term debt, less current portion	(11,743)		(11,103)
Deferred income taxes	0		0
Environmental and asset retirement obligations, less current portion	0		0
Investments in consolidated subsidiaries	(11,322)		(11,091)
Other liabilities	(3,487)		(3,486)
Total liabilities	(27,150)		(26,297)
Equity:
Stockholders' equity	2,272		601
Noncontrolling interests	5,454		5,412
Total equity	7,726		6,013
Total liabilities and equity	(19,424)		(20,284)
FCX Issuer [Member] | Reportable Legal Entities [Member]
ASSETS
Current assets, other than assets held-for-sale	84		309
Property, plant, equipment and mine development costs, net	18		19
Investments in consolidated subsidiaries	17,773		19,064
Other assets	1,335		880
Total assets	19,210		20,272
LIABILITIES AND EQUITY
Current liabilities, other than liabilities held for sale	255		245
Long-term debt, less current portion	8,595		9,594
Deferred income taxes	561		524
Environmental and asset retirement obligations, less current portion	0		0
Investments in consolidated subsidiaries	0		0
Other liabilities	90		111
Total liabilities	9,501		10,474
Equity:
Stockholders' equity	9,709		9,798
Noncontrolling interests	0		0
Total equity	9,709		9,798
Total liabilities and equity	19,210		20,272
FM O&G LLC Guarantor [Member] | Reportable Legal Entities [Member]
ASSETS
Current assets, other than assets held-for-sale	570		620
Property, plant, equipment and mine development costs, net	2		7
Investments in consolidated subsidiaries	0		0
Other assets	21		23
Total assets	593		650
LIABILITIES AND EQUITY
Current liabilities, other than liabilities held for sale	55		34
Long-term debt, less current portion	7,097		6,984
Deferred income taxes	0		0
Environmental and asset retirement obligations, less current portion	234		227
Investments in consolidated subsidiaries	594		578
Other liabilities	3,340		3,340
Total liabilities	11,320		11,163
Equity:
Stockholders' equity	(10,727)		(10,513)
Noncontrolling interests	0		0
Total equity	(10,727)		(10,513)
Total liabilities and equity	593		650
Non-Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member]
ASSETS
Current assets, other than assets held-for-sale	8,634		10,376
Property, plant, equipment and mine development costs, net	28,821		27,984
Investments in consolidated subsidiaries	0		0
Other assets	3,252		3,218
Total assets	40,707		41,578
LIABILITIES AND EQUITY
Current liabilities, other than liabilities held for sale	3,574		3,667
Long-term debt, less current portion	5,963		5,649
Deferred income taxes	3,494		3,508
Environmental and asset retirement obligations, less current portion	3,383		3,382
Investments in consolidated subsidiaries	10,728		10,513
Other liabilities	2,456		2,265
Total liabilities	29,598		28,984
Equity:
Stockholders' equity	8,455		9,912
Noncontrolling interests	2,654		2,682
Total equity	11,109		12,594
Total liabilities and equity	$ 40,707		$ 41,578