Guarantor Financial Statements (Unaudited) Condensed Consolidating Statements of Cash Flows (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Cash flow from operating activities:
Net loss	$ (4,101)	$ (2,406)
Adjustments to reconcile net (loss) income to net cash (used in) provided by operating activities:
Depreciation, depletion and amortization	722	939
Impairment of oil and gas properties	3,787	3,104
Net gains on crude oil derivative contracts	0	(52)
Equity in losses (earnings) of consolidated subsidiaries	(7)	(1)
Other, net	151	(781)
Changes in working capital and other tax payments	188	(86)
Net cash provided by operating activities	740	717
Cash flow from investing activities:
Capital expenditures	(982)	(1,867)
Intercompany loans	0	0
Dividends from (investments in) consolidated subsidiaries	0	0
Other, net	2	127
Net cash used in investing activities	(980)	(1,740)
Cash flow from financing activities:
Proceeds from debt	1,796	2,273
Repayments of debt	(1,442)	(802)
Intercompany loans	0	0
Net proceeds from sale of common Stock	32	0
Cash dividends and distributions paid, and contributions received	(22)	(350)
Other, net	(17)	(13)
Net cash provided by financing activities	347	1,108
Net increase in cash and cash equivalents	107	85
Cash and cash equivalents at beginning of year	224	464
Cash and cash equivalents at end of period	331	549
FCX Issuer [Member]
Cash flow from operating activities:
Net loss	(4,183)	(2,474)
Adjustments to reconcile net (loss) income to net cash (used in) provided by operating activities:
Depreciation, depletion and amortization	1	1
Impairment of oil and gas properties	0	0
Net gains on crude oil derivative contracts		0
Equity in losses (earnings) of consolidated subsidiaries	2,286	1,951
Other, net	127	(701)
Changes in working capital and other tax payments	1,652	1,171
Net cash provided by operating activities	(117)	(52)
Cash flow from investing activities:
Capital expenditures	0	0
Intercompany loans	(561)	(905)
Dividends from (investments in) consolidated subsidiaries	358	310
Other, net	0	0
Net cash used in investing activities	(203)	(595)
Cash flow from financing activities:
Proceeds from debt	1,060	1,515
Repayments of debt	(750)	(530)
Intercompany loans	0	0
Net proceeds from sale of common Stock	32
Cash dividends and distributions paid, and contributions received	(4)	(327)
Other, net	(18)	(11)
Net cash provided by financing activities	320	647
Net increase in cash and cash equivalents	0	0
Cash and cash equivalents at beginning of year	0	0
Cash and cash equivalents at end of period	0	0
FM O&G LLC Guarantor [Member]
Cash flow from operating activities:
Net loss	(3,643)	(2,343)
Adjustments to reconcile net (loss) income to net cash (used in) provided by operating activities:
Depreciation, depletion and amortization	51	119
Impairment of oil and gas properties	1,291	1,062
Net gains on crude oil derivative contracts		(52)
Equity in losses (earnings) of consolidated subsidiaries	2,704	2,359
Other, net	7	6
Changes in working capital and other tax payments	(442)	(1,321)
Net cash provided by operating activities	(32)	(170)
Cash flow from investing activities:
Capital expenditures	(244)	(302)
Intercompany loans	(377)	(400)
Dividends from (investments in) consolidated subsidiaries	(41)	(14)
Other, net	2	0
Net cash used in investing activities	(660)	(716)
Cash flow from financing activities:
Proceeds from debt	0	0
Repayments of debt	0	0
Intercompany loans	716	903
Net proceeds from sale of common Stock	0
Cash dividends and distributions paid, and contributions received	0	0
Other, net	(24)	(18)
Net cash provided by financing activities	692	885
Net increase in cash and cash equivalents	0	(1)
Cash and cash equivalents at beginning of year	0	1
Cash and cash equivalents at end of period	0	0
Non-Guarantor Subsidiaries [Member]
Cash flow from operating activities:
Net loss	(4,899)	(5,440)
Adjustments to reconcile net (loss) income to net cash (used in) provided by operating activities:
Depreciation, depletion and amortization	677	835
Impairment of oil and gas properties	2,483	2,042
Net gains on crude oil derivative contracts		0
Equity in losses (earnings) of consolidated subsidiaries	3,630	3,530
Other, net	17	(86)
Changes in working capital and other tax payments	(1,024)	58
Net cash provided by operating activities	884	939
Cash flow from investing activities:
Capital expenditures	(736)	(1,565)
Intercompany loans	0	0
Dividends from (investments in) consolidated subsidiaries	35	32
Other, net	0	127
Net cash used in investing activities	(701)	(1,406)
Cash flow from financing activities:
Proceeds from debt	736	758
Repayments of debt	(692)	(272)
Intercompany loans	222	402
Net proceeds from sale of common Stock	42
Cash dividends and distributions paid, and contributions received	(373)	(319)
Other, net	(11)	(16)
Net cash provided by financing activities	(76)	553
Net increase in cash and cash equivalents	107	86
Cash and cash equivalents at beginning of year	224	463
Cash and cash equivalents at end of period	331	549
Eliminations [Member]
Cash flow from operating activities:
Net loss	8,624	7,851
Adjustments to reconcile net (loss) income to net cash (used in) provided by operating activities:
Depreciation, depletion and amortization	(7)	(16)
Impairment of oil and gas properties	13	0
Net gains on crude oil derivative contracts		0
Equity in losses (earnings) of consolidated subsidiaries	(8,627)	(7,841)
Other, net	0	0
Changes in working capital and other tax payments	2	6
Net cash provided by operating activities	5	0
Cash flow from investing activities:
Capital expenditures	(2)	0
Intercompany loans	938	1,305
Dividends from (investments in) consolidated subsidiaries	(352)	(328)
Other, net	0	0
Net cash used in investing activities	584	977
Cash flow from financing activities:
Proceeds from debt	0	0
Repayments of debt	0	0
Intercompany loans	(938)	(1,305)
Net proceeds from sale of common Stock	(42)
Cash dividends and distributions paid, and contributions received	355	296
Other, net	36	32
Net cash provided by financing activities	(589)	(977)
Net increase in cash and cash equivalents	0	0
Cash and cash equivalents at beginning of year	0	0
Cash and cash equivalents at end of period	$ 0	$ 0