Acquisitions (Unaudited) Purchase Price Allocation (Details) (USD $)	3 Months Ended				3 Months Ended			3 Months Ended
	Sep. 30, 2013	Jun. 03, 2013		Dec. 31, 2012	Sep. 30, 2013 Plains Exploration & Production Company [Member]	May 31, 2013 Plains Exploration & Production Company [Member]		Sep. 30, 2013 McMoRan Exploration Co [Member]	Jun. 03, 2013 McMoRan Exploration Co [Member]		May 31, 2013 McMoRan Exploration Co [Member]	Jun. 03, 2013 Eliminations [Member]
Business Combination, Separately Recognized Transactions [Line Items]
Current assets		$ 1,290,000,000				$ 1,192,000,000			$ 98,000,000			$ 0
Oil and gas properties - full cost method:
Subject to depletion	12,200,000,000	12,203,000,000				11,447,000,000			756,000,000			0
Not subject to depletion	11,100,000,000	11,117,000,000				9,431,000,000			1,686,000,000			0
Property, plant and equipment		262,000,000				261,000,000			1,000,000			0
Investment in MMR		0	[1]			848,000,000	[1]		0	[1]	848,000,000	(848,000,000)	[1]
Other assets		433,000,000				12,000,000			421,000,000			0
Current liabilities		1,081,000,000				907,000,000			174,000,000			0
Debt (current and long-term)		11,251,000,000				10,631,000,000			620,000,000			0
Deferred income taxes		3,956,000,000	[2]			3,956,000,000	[2]		0	[2]		0	[2]
Other long-term liabilities		1,063,000,000				805,000,000			258,000,000			0
Redeemable noncontrolling interest		972,000,000				713,000,000			259,000,000			0
Total fair value, excluding goodwill		6,982,000,000				6,179,000,000			1,651,000,000			(848,000,000)
Goodwill	1,932,000,000	1,932,000,000		0		455,000,000			1,477,000,000			0
Total purchase price		8,914,000,000				6,634,000,000			3,128,000,000			(848,000,000)
Tax Rate, Fair Value Adjustments, Percent	38.00%
Federal Statutory Income Tax Rate, Percent	35.00%
State Income Taxes, Percent	3.00%
Increase in current assets (primarily current deferred income tax asset)	184				182			2
(Decrease) in oil and gas properties - full cost method:
Subject to depletion	(45)				0			(45)
Not subject to depletion	(210)				(204)			(6)
Increase in other assets (deferred income tax asset)	22				0			22
Net (increase) in deferred income tax liability	(85)				(85)			0
Net decrease in other liabilities (primarily warrants)	70				70			0
Decrease in redeemable noncontrolling interest	36				36			0
Increase in goodwill	28				1			27
Business Combination, Reclassification of Recognized Identifiable Assets Acquired And Liabilities Assumed Deferred Tax Liabilities Noncurrent to Current Tax Assets	$ 162,000,000

[1] PXP owned 51 million shares of MMR common stock, which was eliminated in FCX's condensed consolidated balance sheet at the acquisition date of MMR.

[2] Deferred income taxes have been recognized based on the estimated fair value adjustments to net assets using a 38 percent tax rate, which reflected the 35 percent federal statutory rate and a 3 percent weighted-average of the applicable statutory state tax rates (net of federal benefit).