Guarantor Financial Statements (Unaudited) Condensed Consolidating Statements of Cash Flows (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Cash flow from operating activities:
Net (loss) income	$ (1,799)	$ 660	$ (4,205)	$ 1,286
Adjustments to reconcile net (loss) income to net cash (used in) provided by operating activities:
Depreciation, depletion and amortization	890	1,013	1,829	1,979
Impairment of oil and gas properties	2,686	0	5,790	0
Net (gains) losses on crude oil and natural gas derivative contracts			(58)	120
Net gain on early extinguishment of debt	0	(5)	0	(5)
Equity in losses (earnings) of consolidated subsidiaries			(1)	(2)
Other, net			(1,379)	(14)
Changes in working capital and other tax payments			(190)	(777)
Net cash provided by operating activities			1,786	2,587
Cash flow from investing activities:
Capital expenditures	(1,661)	(1,950)	(3,528)	(3,562)
Acquisition of Deepwater Gulf of Mexico interests			0	(925)
Intercompany loans			0	0
Dividends from (investments in) consolidated subsidiaries			0	0
Net proceeds from sale of Eagle Ford shale assets			0	3,009
Other, net			136	(363)
Net cash used in investing activities			(3,392)	(1,841)
Cash flow from financing activities:
Proceeds from debt			4,422	1,248
Repayments of debt			(2,360)	(1,611)
Intercompany loans			0	0
Cash dividends and distributions paid, and contributions received			(440)	(903)
Other, net			(14)	(7)
Net cash provided by (used in) financing activities			1,608	(1,273)
Net increase (decrease) in cash and cash equivalents			2	(527)
Cash and cash equivalents at beginning of year			464	1,985
Cash and cash equivalents at end of period	466	1,458	466	1,458
FCX Issuer [Member]
Cash flow from operating activities:
Net (loss) income	(1,851)	482	(4,325)	992
Adjustments to reconcile net (loss) income to net cash (used in) provided by operating activities:
Depreciation, depletion and amortization			2	2
Impairment of oil and gas properties			0
Net (gains) losses on crude oil and natural gas derivative contracts			0	0
Net gain on early extinguishment of debt		1		1
Equity in losses (earnings) of consolidated subsidiaries			3,524	(1,152)
Other, net			(1,431)	121
Changes in working capital and other tax payments			2,222	(164)
Net cash provided by operating activities			(8)	(200)
Cash flow from investing activities:
Capital expenditures			0	0
Acquisition of Deepwater Gulf of Mexico interests				0
Intercompany loans			(1,073)	1,318
Dividends from (investments in) consolidated subsidiaries			438	(364)
Net proceeds from sale of Eagle Ford shale assets				0
Other, net			(10)	0
Net cash used in investing activities			(645)	954
Cash flow from financing activities:
Proceeds from debt			2,735	890
Repayments of debt			(1,690)	(990)
Intercompany loans			0	0
Cash dividends and distributions paid, and contributions received			(380)	(653)
Other, net			(12)	(1)
Net cash provided by (used in) financing activities			653	(754)
Net increase (decrease) 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	0	0
FM O&G LLC Guarantor [Member]
Cash flow from operating activities:
Net (loss) income	(2,596)	196	(5,680)	360
Adjustments to reconcile net (loss) income to net cash (used in) provided by operating activities:
Depreciation, depletion and amortization			223	545
Impairment of oil and gas properties	990		2,052
Net (gains) losses on crude oil and natural gas derivative contracts			(58)	120
Net gain on early extinguishment of debt		(6)		(6)
Equity in losses (earnings) of consolidated subsidiaries			4,279	(256)
Other, net			9	(12)
Changes in working capital and other tax payments			(550)	(2,165)
Net cash provided by operating activities			275	(1,414)
Cash flow from investing activities:
Capital expenditures			(734)	(897)
Acquisition of Deepwater Gulf of Mexico interests				0
Intercompany loans			(794)	1,629
Dividends from (investments in) consolidated subsidiaries			(31)	(96)
Net proceeds from sale of Eagle Ford shale assets				3,009
Other, net			(1)	(381)
Net cash used in investing activities			(1,560)	3,264
Cash flow from financing activities:
Proceeds from debt			0	0
Repayments of debt			0	(224)
Intercompany loans			1,321	(170)
Cash dividends and distributions paid, and contributions received			0	(1,453)
Other, net			(37)	(2)
Net cash provided by (used in) financing activities			1,284	(1,849)
Net increase (decrease) in cash and cash equivalents			(1)	1
Cash and cash equivalents at beginning of year			1	0
Cash and cash equivalents at end of period	0	1	0	1
Non-Guarantor Subsidiaries [Member]
Cash flow from operating activities:
Net (loss) income	(3,819)	804	(8,518)	1,674
Adjustments to reconcile net (loss) income to net cash (used in) provided by operating activities:
Depreciation, depletion and amortization			1,638	1,440
Impairment of oil and gas properties	1,674		3,717
Net (gains) losses on crude oil and natural gas derivative contracts			0	0
Net gain on early extinguishment of debt		0		0
Equity in losses (earnings) of consolidated subsidiaries			6,502	39
Other, net			43	(123)
Changes in working capital and other tax payments			(1,870)	1,552
Net cash provided by operating activities			1,512	4,582
Cash flow from investing activities:
Capital expenditures			(2,787)	(2,665)
Acquisition of Deepwater Gulf of Mexico interests				(925)
Intercompany loans			0	0
Dividends from (investments in) consolidated subsidiaries			74	1,079
Net proceeds from sale of Eagle Ford shale assets				0
Other, net			137	18
Net cash used in investing activities			(2,576)	(2,493)
Cash flow from financing activities:
Proceeds from debt			1,687	358
Repayments of debt			(670)	(397)
Intercompany loans			546	(2,777)
Cash dividends and distributions paid, and contributions received			(481)	203
Other, net			(15)	(4)
Net cash provided by (used in) financing activities			1,067	(2,617)
Net increase (decrease) in cash and cash equivalents			3	(528)
Cash and cash equivalents at beginning of year			463	1,985
Cash and cash equivalents at end of period	466	1,457	466	1,457
Eliminations [Member]
Cash flow from operating activities:
Net (loss) income	6,467	(822)	14,318	(1,740)
Adjustments to reconcile net (loss) income to net cash (used in) provided by operating activities:
Depreciation, depletion and amortization			(34)	(8)
Impairment of oil and gas properties			21
Net (gains) losses on crude oil and natural gas derivative contracts			0	0
Net gain on early extinguishment of debt		0		0
Equity in losses (earnings) of consolidated subsidiaries			(14,306)	1,367
Other, net			0	0
Changes in working capital and other tax payments			8	0
Net cash provided by operating activities			7	(381)
Cash flow from investing activities:
Capital expenditures			(7)	0
Acquisition of Deepwater Gulf of Mexico interests				0
Intercompany loans			1,867	(2,947)
Dividends from (investments in) consolidated subsidiaries			(481)	(619)
Net proceeds from sale of Eagle Ford shale assets				0
Other, net			10	0
Net cash used in investing activities			1,389	(3,566)
Cash flow from financing activities:
Proceeds from debt			0	0
Repayments of debt			0	0
Intercompany loans			(1,867)	2,947
Cash dividends and distributions paid, and contributions received			421	1,000
Other, net			50	0
Net cash provided by (used in) financing activities			(1,396)	3,947
Net increase (decrease) 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	$ 0	$ 0