FAIR VALUE MEASUREMENT (Carrying Amount and FV of Other Financial Instruments) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009	Dec. 31, 2008
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	$ 4,822		$ 3,738		$ 2,656	$ 872
Carrying Amount [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	4,822	[1]	3,738	[1]
MMR cost investment	475	[2]	500	[2]
Net embedded derivatives included in accounts receivable or payable	(10)		242
Trust assets (current and long-term)	152	[1],[3]	148	[1],[3]
Available-for-sale securities (current and long-term)	11	[1],[3]	34	[1],[3]
Derivative assets	5	[1],[4]	18	[1],[4]
Derivative liabilities	(13)	[1],[5]	(10)	[1],[5]
Debt (including amounts due within one year)	(3,537)	[6]	(4,755)	[6]
Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	4,822	[1]	3,738	[1]
MMR cost investment	507	[2]	623	[2]
Net embedded derivatives included in accounts receivable or payable	(10)		242
Trust assets (current and long-term)	152	[1],[3]	148	[1],[3]
Available-for-sale securities (current and long-term)	11	[1],[3]	34	[1],[3]
Derivative assets	5	[1],[4]	18	[1],[4]
Derivative liabilities	(13)	[1],[5]	(10)	[1],[5]
Debt (including amounts due within one year)	$ (3,797)	[6]	$ (5,146)	[6]

[1] Recorded at fair value.

[2] Recorded at cost and included in other assets. At December 31, 2011, these securities were not actively trading; as such, fair value was based on a pricing simulation model using MMR's publicly traded common stock as the most significant observable input. At December 31, 2010, fair value was based on a bid evaluation, which is an estimated price at which a dealer would pay for a security.

[3] Current portion included in other current assets and long-term portion included in other assets.

[4] Included in other current assets.

[5] Included in accounts payable and accrued liabilities.

[6] Recorded at cost except for long-term debt acquired in the FMC acquisition, which was recorded at fair value at the acquisition date. Fair value of substantially all of FCX’s long-term debt is estimated based on quoted market prices.