Guarantor Financial Statements (Unaudited) Condensed Consolidating Statements of Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Revenues	$ 3,546	$ 5,168	$ 7,338	$ 10,036
Total costs and expenses	3,513	3,504	6,984	6,913
Operating income (loss)	33	1,664	354	3,123
Interest expense, net	(132)	(142)	(278)	(293)
Other Nonoperating Income (Expense)	5	29	13	57
Net gain (loss) on early extinguishment of debt	0	9	(6)	8
(Loss) income from continuing operations before income taxes and equity in affiliated companies’ net earnings	(94)	1,551	89	2,887
Benefit from (provision for) income taxes	15	(515)	(90)	(1,021)
Equity in affiliated companies’ net earnings (losses)	5	3	2	1
Net (loss) income from continuing operations	(74)	1,039	1	1,867
Net (loss) income from discontinued operations	0	(4)	1	(15)
Net income	(74)	1,035	2	1,852
Net loss (income) from continuing operations attributable to noncontrolling interests	2	(166)	(43)	(291)
Net (loss) income attributable to common stockholders	(72)	869	(41)	1,561
Other comprehensive income (loss)	12	11	23	23
Total comprehensive income (loss)	(60)	880	(18)	1,584
Eliminations [Member]
Revenues	0	0	0	0
Total costs and expenses	2	(9)	0	(10)
Operating income (loss)	(2)	9	0	10
Interest expense, net	135	123	274	225
Other Nonoperating Income (Expense)	(1)	(123)	(74)	(225)
(Loss) income from continuing operations before income taxes and equity in affiliated companies’ net earnings	132	9	200	10
Benefit from (provision for) income taxes	0	(2)	0	(2)
Equity in affiliated companies’ net earnings (losses)	92	(803)	77	(1,552)
Net (loss) income from continuing operations		(796)	277	(1,544)
Net (loss) income from discontinued operations		0	0	0
Net income	224	(796)	277	(1,544)
Net loss (income) from continuing operations attributable to noncontrolling interests	10	(64)	(1)	(118)
Net (loss) income attributable to common stockholders	234	(860)	276	(1,662)
Other comprehensive income (loss)	(12)	(11)	(23)	(23)
Total comprehensive income (loss)	222	(871)	253	(1,685)
FCX Issuer [Member] | Reportable Legal Entities [Member]
Revenues	0	0	0	0
Total costs and expenses	4	4	17	13
Operating income (loss)	(4)	(4)	(17)	(13)
Interest expense, net	(83)	(97)	(173)	(201)
Other Nonoperating Income (Expense)	(1)	132	64	233
(Loss) income from continuing operations before income taxes and equity in affiliated companies’ net earnings	(88)	31	(126)	19
Benefit from (provision for) income taxes	(7)	(11)	(8)	(94)
Equity in affiliated companies’ net earnings (losses)	23	849	93	1,636
Net (loss) income from continuing operations		869	(41)	1,561
Net (loss) income from discontinued operations		0	0	0
Net income	(72)	869	(41)	1,561
Net loss (income) from continuing operations attributable to noncontrolling interests	0	0	0	0
Net (loss) income attributable to common stockholders	(72)	869	(41)	1,561
Other comprehensive income (loss)	12	11	23	23
Total comprehensive income (loss)	(60)	880	(18)	1,584
FM O&G LLC Guarantor [Member] | Reportable Legal Entities [Member]
Revenues	13	16	16	31
Total costs and expenses	26	(16)	26	(8)
Operating income (loss)	(13)	32	(10)	39
Interest expense, net	(82)	(76)	(168)	(140)
Other Nonoperating Income (Expense)	0	2	0	2
(Loss) income from continuing operations before income taxes and equity in affiliated companies’ net earnings	(95)	(42)	(178)	(99)
Benefit from (provision for) income taxes	22	10	40	22
Equity in affiliated companies’ net earnings (losses)	(21)	2	(16)	(4)
Net (loss) income from continuing operations		(30)	(154)	(81)
Net (loss) income from discontinued operations		0	0	0
Net income	(94)	(30)	(154)	(81)
Net loss (income) from continuing operations attributable to noncontrolling interests	0	0	0	0
Net (loss) income attributable to common stockholders	(94)	(30)	(154)	(81)
Other comprehensive income (loss)	0	0	0	0
Total comprehensive income (loss)	(94)	(30)	(154)	(81)
Non-Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member]
Revenues	3,533	5,152	7,322	10,005
Total costs and expenses	3,481	3,525	6,941	6,918
Operating income (loss)	52	1,627	381	3,087
Interest expense, net	(102)	(92)	(211)	(177)
Other Nonoperating Income (Expense)	7	18	23	47
(Loss) income from continuing operations before income taxes and equity in affiliated companies’ net earnings	(43)	1,553	193	2,957
Benefit from (provision for) income taxes	0	(512)	(122)	(947)
Equity in affiliated companies’ net earnings (losses)	(89)	(45)	(152)	(79)
Net (loss) income from continuing operations		996	(81)	1,931
Net (loss) income from discontinued operations		(4)	1	(15)
Net income	(132)	992	(80)	1,916
Net loss (income) from continuing operations attributable to noncontrolling interests	(8)	(102)	(42)	(173)
Net (loss) income attributable to common stockholders	(140)	890	(122)	1,743
Other comprehensive income (loss)	12	11	23	23
Total comprehensive income (loss)	$ (128)	$ 901	$ (99)	$ 1,766