FINANCIAL INSTRUMENTS (Unsettled Derivatives) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011		Dec. 31, 2010
Derivatives, Fair Value [Line Items]
Paid to brokers associated with margin requirements	$ 31		$ 3
Received from customers associated with margin requirements	3
Received from brokers associated with margin requirements			8
Derivatives designated as hedging instruments [Member] | FMC's Copper Futures and Swap Contracts [Member] | Other current assets [Member]
Derivatives, Fair Value [Line Items]
Asset position	3	[1],[2]	18	[1],[2]
Derivatives designated as hedging instruments [Member] | FMC's Copper Futures and Swap Contracts [Member] | Accounts payable and accrued liabilities [Member]
Derivatives, Fair Value [Line Items]
Liability position	(13)	[1],[3]	0	[1],[3]
Derivatives not designated as hedging instruments [Member] | Embedded derivatives in provisional sales purchases contracts [Member] | Net accounts receivable [Member]
Derivatives, Fair Value [Line Items]
Asset position	72	[4]	357	[4]
Derivatives not designated as hedging instruments [Member] | Embedded derivatives in provisional sales purchases contracts [Member] | Net accounts payable [Member]
Derivatives, Fair Value [Line Items]
Liability position	(82)	[4]	(115)	[4]
Derivatives not designated as hedging instruments [Member] | Atlantic Copper's copper forward contracts [Member] | Other current assets [Member]
Derivatives, Fair Value [Line Items]
Asset position	2	[2]	0	[2]
Derivatives not designated as hedging instruments [Member] | Atlantic Copper's copper forward contracts [Member] | Accounts payable and accrued liabilities [Member]
Derivatives, Fair Value [Line Items]
Liability position	$ 0	[3]	$ (10)	[3]

[1] FCX had paid $31 million to brokers at December 31, 2011, and $3 million at December 31, 2010, for margin requirements (recorded in other current assets). In addition, FCX held $3 million in margin funding from customers at December 31, 2011, and $8 million from brokers at December 31, 2010, associated with margin requirements (recorded in accounts payable and accrued liabilities).

[2] Amounts recorded in other current assets.

[3] Amounts recorded in accounts payable and accrued liabilities.

[4] Amounts recorded either as a net accounts receivable or a net accounts payable.