Financial Instruments (Unaudited) Unsettled Derivatives (Details) (USD $) In Millions	Sep. 30, 2011		Dec. 31, 2010
Derivatives, Fair Value [Line Items]
Paid to brokers associated with margin requirements	$ 55		$ 3
Received from customers associated with margin requirements	28
Received from brokers associated with margin requirements			8
FMC's Copper Futures and Swap Contracts [Member] | Derivatives designated as hedging instruments [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Asset position	0	[1],[2]	18	[1],[2]
FMC's Copper Futures and Swap Contracts [Member] | Derivatives designated as hedging instruments [Member] | Accounts payable and accrued liabilities [Member]
Derivatives, Fair Value [Line Items]
Liability position	(54)	[2],[3]	0	[2],[3]
Atlantic Copper's copper forward contracts [Member] | Derivatives not designated as hedging instruments | Accounts payable and accrued liabilities [Member]
Derivatives, Fair Value [Line Items]
Liability position	(1)	[3]	(10)	[3]
Embedded derivatives in provisional sales/purchases contracts [Member] | Derivatives not designated as hedging instruments | Net accounts receivable [Member]
Derivatives, Fair Value [Line Items]
Asset position	179	[4]	357	[4]
Embedded derivatives in provisional sales/purchases contracts [Member] | Derivatives not designated as hedging instruments | Net accounts payable [Member]
Derivatives, Fair Value [Line Items]
Liability position	$ (581)	[4]	$ (115)	[4]

[1] Amounts recorded in other current assets.

[2] FCX had paid $55 million to brokers at September 30, 2011, and $3 million at December 31, 2010, for margin requirements (recorded in other current assets). In addition, FCX held $28 million in margin funding from customers at September 30, 2011, and $8 million from brokers at December 31, 2010, associated with margin requirements (recorded in accounts payable and accrued liabilities).

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

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