Guarantor Financial Statements (Unaudited) Condensed Consolidating Statements of Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Revenues	$ 3,153	$ 4,908	$ 10,491	$ 14,944
Total costs and expenses	3,191	3,593	10,175	10,506
Operating income (loss)	(38)	1,315	316	4,438
Interest expense, net	(123)	(143)	(401)	(436)
Other Nonoperating Income (Expense)	12	14	25	71
Net (loss) gain on early extinguishment of debt	(21)	0	(27)	8
(Loss) income from continuing operations before income taxes and equity in affiliated companies’ net earnings	(149)	1,186	(60)	4,073
Provision for income taxes	(91)	(522)	(181)	(1,543)
Equity in affiliated companies’ net earnings (losses)	5	4	7	5
Net (loss) income from continuing operations	(235)	668	(234)	2,535
Net income (loss) from discontinued operations	1	(4)	2	(19)
Net income	(234)	664	(232)	2,516
Net loss (income) from continuing operations attributable to noncontrolling interests	27	(108)	(16)	(399)
Net (loss) income attributable to common stockholders	(207)	556	(248)	2,117
Other comprehensive income (loss)	12	11	35	34
Total comprehensive income (loss)	(195)	567	(213)	2,151
Eliminations [Member]
Revenues	0	0	0	0
Total costs and expenses	(7)	0	(7)	(10)
Operating income (loss)	7	0	7	10
Interest expense, net	133	125	407	350
Other Nonoperating Income (Expense)	28	(125)	(46)	(350)
(Loss) income from continuing operations before income taxes and equity in affiliated companies’ net earnings	168	0	368	10
Provision for income taxes	(2)	0	(2)	(2)
Equity in affiliated companies’ net earnings (losses)	191	(656)	268	(2,208)
Net (loss) income from continuing operations	357	(656)	634	(2,200)
Net income (loss) from discontinued operations	0	0	0	0
Net income	357	(656)	634	(2,200)
Net loss (income) from continuing operations attributable to noncontrolling interests	5	(61)	4	(179)
Net (loss) income attributable to common stockholders	362	(717)	638	(2,379)
Other comprehensive income (loss)	(12)	(11)	(35)	(34)
Total comprehensive income (loss)	350	(728)	603	(2,413)
FCX Issuer [Member] | Reportable Legal Entities [Member]
Revenues	0	0	0	0
Total costs and expenses	5	7	22	20
Operating income (loss)	(5)	(7)	(22)	(20)
Interest expense, net	(79)	(93)	(252)	(294)
Other Nonoperating Income (Expense)	(52)	124	12	357
(Loss) income from continuing operations before income taxes and equity in affiliated companies’ net earnings	(136)	24	(262)	43
Provision for income taxes	(26)	(188)	(34)	(282)
Equity in affiliated companies’ net earnings (losses)	(45)	720	48	2,356
Net (loss) income from continuing operations	(207)	556	(248)	2,117
Net income (loss) from discontinued operations	0	0	0	0
Net income	(207)	556	(248)	2,117
Net loss (income) from continuing operations attributable to noncontrolling interests	0	0	0	0
Net (loss) income attributable to common stockholders	(207)	556	(248)	2,117
Other comprehensive income (loss)	12	11	35	34
Total comprehensive income (loss)	(195)	567	(213)	2,151
FM O&G LLC Guarantor [Member] | Reportable Legal Entities [Member]
Revenues	11	15	27	46
Total costs and expenses	28	(2)	54	(10)
Operating income (loss)	(17)	17	(27)	56
Interest expense, net	(79)	(79)	(247)	(219)
Other Nonoperating Income (Expense)	0	0	0	2
(Loss) income from continuing operations before income taxes and equity in affiliated companies’ net earnings	(96)	(62)	(274)	(161)
Provision for income taxes	22	11	62	33
Equity in affiliated companies’ net earnings (losses)	(36)	(6)	(52)	(10)
Net (loss) income from continuing operations	(110)	(57)	(264)	(138)
Net income (loss) from discontinued operations	0	0	0	0
Net income	(110)	(57)	(264)	(138)
Net loss (income) from continuing operations attributable to noncontrolling interests	0	0	0	0
Net (loss) income attributable to common stockholders	(110)	(57)	(264)	(138)
Other comprehensive income (loss)	0	0	0	0
Total comprehensive income (loss)	(110)	(57)	(264)	(138)
Non-Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member]
Revenues	3,142	4,893	10,464	14,898
Total costs and expenses	3,165	3,588	10,106	10,506
Operating income (loss)	(23)	1,305	358	4,392
Interest expense, net	(98)	(96)	(309)	(273)
Other Nonoperating Income (Expense)	36	15	59	62
(Loss) income from continuing operations before income taxes and equity in affiliated companies’ net earnings	(85)	1,224	108	4,181
Provision for income taxes	(85)	(345)	(207)	(1,292)
Equity in affiliated companies’ net earnings (losses)	(105)	(54)	(257)	(133)
Net (loss) income from continuing operations	(275)	825	(356)	2,756
Net income (loss) from discontinued operations	1	(4)	2	(19)
Net income	(274)	821	(354)	2,737
Net loss (income) from continuing operations attributable to noncontrolling interests	22	(47)	(20)	(220)
Net (loss) income attributable to common stockholders	(252)	774	(374)	2,517
Other comprehensive income (loss)	12	11	35	34
Total comprehensive income (loss)	$ (240)	$ 785	$ (339)	$ 2,551