Financial Instruments (Unaudited) Unsettled Derivatives (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012		Dec. 31, 2011
Derivatives, Fair Value [Line Items]
Paid to brokers associated with margin requirements	$ 12		$ 31
Received from customers associated with margin requirements			3
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	10	[1],[2]	3	[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	(3)	[2],[3]	(13)	[2],[3]
Atlantic Copper's copper forward contracts [Member] | Derivatives not designated as hedging instruments | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Asset position	1	[1]	2	[1]
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	46	[4]	72	[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	$ (29)	[4]	$ (82)	[4]

[1] Amounts recorded in other current assets.

[2] FCX had paid $12 million to brokers at March 31, 2012, and $31 million at December 31, 2011, for margin requirements (recorded in other current assets). In addition, FCX held $3 million in margin funding from customers at December 31, 2011, 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.