Contingencies and Commitments (Unaudited) Asset Retirement Obligations (Details) (USD $)	6 Months Ended
	Jun. 30, 2013
Asset Retirement Obligations Rollforward [Line Items]
Balance at December 31, 2012	$ 1,146,000,000
Liabilities assumed in the acquisitions of PXP and MMR	1,024,000,000	[1]
Liabilities incurred	9,000,000
Revisions to cash flow estimates	15,000,000
Accretion expense	33,000,000
Spending, including oil and gas settlements	(28,000,000)
Balance at June 30, 2013	2,199,000,000
Less current portion	130,000,000
Long-term portion	2,069,000,000
Fair Value Assumptions, Inflation Rate	2.50%
Plains Exploration & Production Company [Member]
Asset Retirement Obligations Rollforward [Line Items]
Liabilities assumed in the acquisitions of PXP and MMR	741,000,000
McMoRan Exploration Co [Member]
Asset Retirement Obligations Rollforward [Line Items]
Liabilities assumed in the acquisitions of PXP and MMR	$ 283,000,000
Minimum [Member]
Asset Retirement Obligations Rollforward [Line Items]
Fair Value Assumptions, Risk Free Interest Rate	1.30%
Maximum [Member]
Asset Retirement Obligations Rollforward [Line Items]
Fair Value Assumptions, Risk Free Interest Rate	6.30%

[1] The fair value of AROs assumed in the acquisitions of PXP and MMR ($741 million and $283 million, respectively) were estimated based on projected cash flows, an estimated long-term annual inflation rate of 2.5 percent, and discount rates based on FCX's estimated credit-adjusted, risk-free interest rates ranging from 1.3 percent to 6.3 percent.