Guarantor Financial Statements (Unaudited) Condensed Consolidating Statements of Cash Flows (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Cash flow from operating activities:
Net income	$ 626	$ 824
Adjustments to reconcile net income (loss) to net cash (used in) provided by operating activities:
Depreciation, depletion and amortization	966	329
Net losses on crude oil and natural gas derivative contracts	50	0
Equity in (earnings) losses of consolidated subsidiaries	0
Other, net	(28)
Increase (Decrease) in Operating Capital	(413)
Net cash provided by operating activities	1,201	831
Cash flow from investing activities:
Capital expenditures	(1,612)	(805)
Intercompany loans	0
Investment in consolidated subsidiary	0
Other, net	7	14
Net cash used in investing activities	(1,605)	(1,112)
Cash flow from financing activities:
Proceeds from debt	1,149	6,615
Repayments of debt	(987)
Intercompany loans	0
Cash dividends and distributions paid	(403)
Other, net	2
Net cash (used in) provided by financing activities	(239)	6,171
Net (decrease) increase in cash and cash equivalents	(643)	5,890
Cash and cash equivalents at beginning of year	1,985	3,705
Cash and cash equivalents at end of period	1,342	9,595
FCX Issuer [Member]
Cash flow from operating activities:
Net income	510
Adjustments to reconcile net income (loss) to net cash (used in) provided by operating activities:
Depreciation, depletion and amortization	1
Net losses on crude oil and natural gas derivative contracts	0
Equity in (earnings) losses of consolidated subsidiaries	(604)
Other, net	134
Increase (Decrease) in Operating Capital	(234)
Net cash provided by operating activities	(193)
Cash flow from investing activities:
Capital expenditures	0
Intercompany loans	190
Investment in consolidated subsidiary	212
Other, net	0
Net cash used in investing activities	402
Cash flow from financing activities:
Proceeds from debt	895
Repayments of debt	(780)
Intercompany loans	0
Cash dividends and distributions paid	(326)
Other, net	2
Net cash (used in) provided by financing activities	(209)
Net (decrease) increase in cash and cash equivalents	0
Cash and cash equivalents at beginning of year	0
Cash and cash equivalents at end of period	0
FM O&G LLC Guarantor [Member]
Cash flow from operating activities:
Net income	164
Adjustments to reconcile net income (loss) to net cash (used in) provided by operating activities:
Depreciation, depletion and amortization	285
Net losses on crude oil and natural gas derivative contracts	50
Equity in (earnings) losses of consolidated subsidiaries	(130)
Other, net	(9)
Increase (Decrease) in Operating Capital	339
Net cash provided by operating activities	699
Cash flow from investing activities:
Capital expenditures	(335)
Intercompany loans	(43)
Investment in consolidated subsidiary	(96)
Other, net	4
Net cash used in investing activities	(470)
Cash flow from financing activities:
Proceeds from debt	0
Repayments of debt	0
Intercompany loans	(213)
Cash dividends and distributions paid	(14)
Other, net	0
Net cash (used in) provided by financing activities	(227)
Net (decrease) increase in cash and cash equivalents	2
Cash and cash equivalents at beginning of year	0
Cash and cash equivalents at end of period	2
Non-Guarantor Subsidiaries [Member]
Cash flow from operating activities:
Net income	870
Adjustments to reconcile net income (loss) to net cash (used in) provided by operating activities:
Depreciation, depletion and amortization	682
Net losses on crude oil and natural gas derivative contracts	0
Equity in (earnings) losses of consolidated subsidiaries	(185)
Other, net	(140)
Increase (Decrease) in Operating Capital	(518)
Net cash provided by operating activities	709
Cash flow from investing activities:
Capital expenditures	(1,277)
Intercompany loans	0
Investment in consolidated subsidiary	(430)
Other, net	3
Net cash used in investing activities	(1,704)
Cash flow from financing activities:
Proceeds from debt	254
Repayments of debt	(207)
Intercompany loans	66
Cash dividends and distributions paid	237
Other, net	0
Net cash (used in) provided by financing activities	350
Net (decrease) increase in cash and cash equivalents	(645)
Cash and cash equivalents at beginning of year	1,985
Cash and cash equivalents at end of period	1,340
Eliminations [Member]
Cash flow from operating activities:
Net income	(918)
Adjustments to reconcile net income (loss) to net cash (used in) provided by operating activities:
Depreciation, depletion and amortization	(2)
Net losses on crude oil and natural gas derivative contracts	0
Equity in (earnings) losses of consolidated subsidiaries	919
Other, net	(13)
Increase (Decrease) in Operating Capital	0
Net cash provided by operating activities	(14)
Cash flow from investing activities:
Capital expenditures	0
Intercompany loans	(147)
Investment in consolidated subsidiary	314
Other, net	0
Net cash used in investing activities	167
Cash flow from financing activities:
Proceeds from debt	0
Repayments of debt	0
Intercompany loans	147
Cash dividends and distributions paid	(300)
Other, net	0
Net cash (used in) provided by financing activities	(153)
Net (decrease) increase in cash and cash equivalents	0
Cash and cash equivalents at beginning of year	0
Cash and cash equivalents at end of period	$ 0