Guarantor Financial Statements (Unaudited) Condensed Consolidating Statements of Cash Flows (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Cash flow from operating activities:
Net income	$ 2,482	$ 3,035
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, depletion and amortization	1,778	856
Net losses on oil and gas derivative contracts	205	0
Losses on early extinguishment of debt	45	168
Gain on investment in McMoRan Exploration Co.	(128)	0
Equity in earnings of consolidated subsidiaries	0
Other, net	(150)
Accounts receivable, inventories and other current assets	147
Accounts payable, accrued liabilities and accrued and other tax payments	(636)
Net cash provided by operating activities	3,743	2,509
Cash flow from investing activities:
Capital expenditures	(3,623)	(2,518)
Acquisitions, net of cash acquired	(5,441)
Intercompany loans	0
Dividends from consolidated subsidiary	0
Other, net	(24)	(19)
Net cash used in investing activities	(9,088)	(2,537)
Cash flow from financing activities:
Proceeds from debt	11,229	3,023
Repayments of debt and redemption of MMR preferred stock	(5,043)
Intercompany loans	0
Cash dividends and distributions paid:
Common stock	(1,957)	(832)
Noncontrolling interests	(157)	(76)
Other, net	(213)
Net cash provided by (used in) financing activities	3,859	(1,067)
Net decrease in cash and cash equivalents	(1,486)	(1,095)
Cash and cash equivalents at beginning of year	3,705	4,822
Cash and cash equivalents at end of period	2,219	3,727
FCX Issuer [Member]
Cash flow from operating activities:
Net income	1,951
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, depletion and amortization	3
Net losses on oil and gas derivative contracts	0
Losses on early extinguishment of debt	45
Gain on investment in McMoRan Exploration Co.	(128)
Equity in earnings of consolidated subsidiaries	(2,096)
Other, net	8
Accounts receivable, inventories and other current assets	89
Accounts payable, accrued liabilities and accrued and other tax payments	23
Net cash provided by operating activities	(105)
Cash flow from investing activities:
Capital expenditures	0
Acquisitions, net of cash acquired	(5,437)
Intercompany loans	793
Dividends from consolidated subsidiary	321
Other, net	14
Net cash used in investing activities	(4,309)
Cash flow from financing activities:
Proceeds from debt	11,085
Repayments of debt and redemption of MMR preferred stock	(4,501)
Intercompany loans	0
Cash dividends and distributions paid:
Common stock	(1,957)
Noncontrolling interests	0
Other, net	(213)
Net cash provided by (used in) financing activities	4,414
Net decrease 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	221
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, depletion and amortization	341
Net losses on oil and gas derivative contracts	205
Losses on early extinguishment of debt	0
Gain on investment in McMoRan Exploration Co.	0
Equity in earnings of consolidated subsidiaries	(207)
Other, net	(15)
Accounts receivable, inventories and other current assets	30
Accounts payable, accrued liabilities and accrued and other tax payments	488
Net cash provided by operating activities	1,063
Cash flow from investing activities:
Capital expenditures	(621)
Acquisitions, net of cash acquired	0
Intercompany loans	0
Dividends from consolidated subsidiary	0
Other, net	32
Net cash used in investing activities	(589)
Cash flow from financing activities:
Proceeds from debt	0
Repayments of debt and redemption of MMR preferred stock	(416)
Intercompany loans	(56)
Cash dividends and distributions paid:
Common stock	0
Noncontrolling interests	0
Other, net	0
Net cash provided by (used in) financing activities	(472)
Net decrease 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	2,611
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, depletion and amortization	1,434
Net losses on oil and gas derivative contracts	0
Losses on early extinguishment of debt	0
Gain on investment in McMoRan Exploration Co.	0
Equity in earnings of consolidated subsidiaries	2
Other, net	(143)
Accounts receivable, inventories and other current assets	28
Accounts payable, accrued liabilities and accrued and other tax payments	(1,147)
Net cash provided by operating activities	2,785
Cash flow from investing activities:
Capital expenditures	(3,002)
Acquisitions, net of cash acquired	(4)
Intercompany loans	(1,095)
Dividends from consolidated subsidiary	0
Other, net	(70)
Net cash used in investing activities	(4,171)
Cash flow from financing activities:
Proceeds from debt	144
Repayments of debt and redemption of MMR preferred stock	(126)
Intercompany loans	358
Cash dividends and distributions paid:
Common stock	(321)
Noncontrolling interests	(157)
Other, net	0
Net cash provided by (used in) financing activities	(102)
Net decrease in cash and cash equivalents	(1,488)
Cash and cash equivalents at beginning of year	3,705
Cash and cash equivalents at end of period	2,217
Eliminations [Member]
Cash flow from operating activities:
Net income	(2,301)
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, depletion and amortization	0
Net losses on oil and gas derivative contracts	0
Losses on early extinguishment of debt	0
Gain on investment in McMoRan Exploration Co.	0
Equity in earnings of consolidated subsidiaries	2,301
Other, net	0
Accounts receivable, inventories and other current assets	0
Accounts payable, accrued liabilities and accrued and other tax payments	0
Net cash provided by operating activities	0
Cash flow from investing activities:
Capital expenditures	0
Acquisitions, net of cash acquired	0
Intercompany loans	302
Dividends from consolidated subsidiary	(321)
Other, net	0
Net cash used in investing activities	(19)
Cash flow from financing activities:
Proceeds from debt	0
Repayments of debt and redemption of MMR preferred stock	0
Intercompany loans	(302)
Cash dividends and distributions paid:
Common stock	321
Noncontrolling interests	0
Other, net	0
Net cash provided by (used in) financing activities	19
Net decrease in cash and cash equivalents	0
Cash and cash equivalents at beginning of year	0
Cash and cash equivalents at end of period	$ 0