EMPLOYEE BENEFITS (Schedule of FV of Financial Assets for Pension Plans) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
FCX plans [Abstract]
Cash and Receivables In Plan Assets	$ 6		$ 81
Payables In Plan Assets	(13)		(93)
Total [Member] | Total [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	1,148		1,124
Total [Member] | Fair Value, Inputs, Level 1 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	207		430
Total [Member] | Fair value, inputs, Level 2 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	856		620
Total [Member] | Fair value, inputs, Level 3 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	85		74
Commingled And Collective Funds [Member] | Global equity core [Member] | Total [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	408
Commingled And Collective Funds [Member] | Global equity core [Member] | Fair Value, Inputs, Level 1 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	0
Commingled And Collective Funds [Member] | Global equity core [Member] | Fair value, inputs, Level 2 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	408
Commingled And Collective Funds [Member] | Global equity core [Member] | Fair value, inputs, Level 3 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	0
Commingled And Collective Funds [Member] | U.S. small cap equity [Member] | Total [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	45		101	[1]
Commingled And Collective Funds [Member] | U.S. small cap equity [Member] | Fair Value, Inputs, Level 1 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	0		0	[1]
Commingled And Collective Funds [Member] | U.S. small cap equity [Member] | Fair value, inputs, Level 2 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	45		101	[1]
Commingled And Collective Funds [Member] | U.S. small cap equity [Member] | Fair value, inputs, Level 3 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	0		0	[1]
Commingled And Collective Funds [Member] | Real Estate Property [Member] | Total [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	35		28
Commingled And Collective Funds [Member] | Real Estate Property [Member] | Fair Value, Inputs, Level 1 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	0		0
Commingled And Collective Funds [Member] | Real Estate Property [Member] | Fair value, inputs, Level 2 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	0		0
Commingled And Collective Funds [Member] | Real Estate Property [Member] | Fair value, inputs, Level 3 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	35		28
Commingled And Collective Funds [Member] | Short-term Investments [Member] | Total [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	22		19	[1]
Commingled And Collective Funds [Member] | Short-term Investments [Member] | Fair Value, Inputs, Level 1 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	0		0	[1]
Commingled And Collective Funds [Member] | Short-term Investments [Member] | Fair value, inputs, Level 2 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	22		19	[1]
Commingled And Collective Funds [Member] | Short-term Investments [Member] | Fair value, inputs, Level 3 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	0		0	[1]
Commingled And Collective Funds [Member] | U.S. large cap equity [Member] | Total [Member]
FCX plans [Abstract]
Fair value of plan assets measurement			134
Commingled And Collective Funds [Member] | U.S. large cap equity [Member] | Fair Value, Inputs, Level 1 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement			0
Commingled And Collective Funds [Member] | U.S. large cap equity [Member] | Fair value, inputs, Level 2 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement			134
Commingled And Collective Funds [Member] | U.S. large cap equity [Member] | Fair value, inputs, Level 3 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement			0
Commingled And Collective Funds [Member] | International Equity Core [Member] | Total [Member]
FCX plans [Abstract]
Fair value of plan assets measurement			71
Commingled And Collective Funds [Member] | International Equity Core [Member] | Fair Value, Inputs, Level 1 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement			0
Commingled And Collective Funds [Member] | International Equity Core [Member] | Fair value, inputs, Level 2 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement			71
Commingled And Collective Funds [Member] | International Equity Core [Member] | Fair value, inputs, Level 3 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement			0
Commingled And Collective Funds [Member] | Real Estate Funds [Member] | Total [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	52		47	[1]
Commingled And Collective Funds [Member] | Real Estate Funds [Member] | Fair Value, Inputs, Level 1 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	0		0	[1]
Commingled And Collective Funds [Member] | Real Estate Funds [Member] | Fair value, inputs, Level 2 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	52		47	[1]
Commingled And Collective Funds [Member] | Real Estate Funds [Member] | Fair value, inputs, Level 3 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	0		0	[1]
Open Ended Mutual Funds [Member] | Government bonds [Member] | Total [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	50		38
Open Ended Mutual Funds [Member] | Government bonds [Member] | Fair Value, Inputs, Level 1 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	50		38
Open Ended Mutual Funds [Member] | Government bonds [Member] | Fair value, inputs, Level 2 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	0		0
Open Ended Mutual Funds [Member] | Government bonds [Member] | Fair value, inputs, Level 3 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	0		0
Open Ended Mutual Funds [Member] | Emerging Markets Equity [Member] | Total [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	36		46
Open Ended Mutual Funds [Member] | Emerging Markets Equity [Member] | Fair Value, Inputs, Level 1 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	36		46
Open Ended Mutual Funds [Member] | Emerging Markets Equity [Member] | Fair value, inputs, Level 2 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	0		0
Open Ended Mutual Funds [Member] | Emerging Markets Equity [Member] | Fair value, inputs, Level 3 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	0		0
Open Ended Mutual Funds [Member] | Corporate bonds [Member] | Total [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	22		30
Open Ended Mutual Funds [Member] | Corporate bonds [Member] | Fair Value, Inputs, Level 1 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	22		30
Open Ended Mutual Funds [Member] | Corporate bonds [Member] | Fair value, inputs, Level 2 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	0		0
Open Ended Mutual Funds [Member] | Corporate bonds [Member] | Fair value, inputs, Level 3 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	0		0
Mutual Funds [Member] | Emerging Markets Equity [Member] | Total [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	24		29
Mutual Funds [Member] | Emerging Markets Equity [Member] | Fair Value, Inputs, Level 1 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	24		29
Mutual Funds [Member] | Emerging Markets Equity [Member] | Fair value, inputs, Level 2 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	0		0
Mutual Funds [Member] | Emerging Markets Equity [Member] | Fair value, inputs, Level 3 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	0		0
Mutual Funds [Member] | Foreign Bonds [Member] | Total [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	43		38
Mutual Funds [Member] | Foreign Bonds [Member] | Fair Value, Inputs, Level 1 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	43		38
Mutual Funds [Member] | Foreign Bonds [Member] | Fair value, inputs, Level 2 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	0		0
Mutual Funds [Member] | Foreign Bonds [Member] | Fair value, inputs, Level 3 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	0		0
Mutual Funds [Member] | Emerging Markets Bonds [Member] | Total [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	32		30
Mutual Funds [Member] | Emerging Markets Bonds [Member] | Fair Value, Inputs, Level 1 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	32		30
Mutual Funds [Member] | Emerging Markets Bonds [Member] | Fair value, inputs, Level 2 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	0		0
Mutual Funds [Member] | Emerging Markets Bonds [Member] | Fair value, inputs, Level 3 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	0		0
Equity securities [Member] | U.S. large cap equity [Member] | Total [Member]
FCX plans [Abstract]
Fair value of plan assets measurement			161
Equity securities [Member] | U.S. large cap equity [Member] | Fair Value, Inputs, Level 1 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement			161
Equity securities [Member] | U.S. large cap equity [Member] | Fair value, inputs, Level 2 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement			0
Equity securities [Member] | U.S. large cap equity [Member] | Fair value, inputs, Level 3 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement			0
Equity securities [Member] | International Equity Value [Member] | Total [Member]
FCX plans [Abstract]
Fair value of plan assets measurement			57
Equity securities [Member] | International Equity Value [Member] | Fair Value, Inputs, Level 1 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement			57
Equity securities [Member] | International Equity Value [Member] | Fair value, inputs, Level 2 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement			0
Equity securities [Member] | International Equity Value [Member] | Fair value, inputs, Level 3 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement			0
Fixed income securities [Member] | Government bonds [Member] | Total [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	233		147
Fixed income securities [Member] | Government bonds [Member] | Fair Value, Inputs, Level 1 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	0		0
Fixed income securities [Member] | Government bonds [Member] | Fair value, inputs, Level 2 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	233		147
Fixed income securities [Member] | Government bonds [Member] | Fair value, inputs, Level 3 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	0		0
Fixed income securities [Member] | Corporate bonds [Member] | Total [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	73		74
Fixed income securities [Member] | Corporate bonds [Member] | Fair Value, Inputs, Level 1 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	0		0
Fixed income securities [Member] | Corporate bonds [Member] | Fair value, inputs, Level 2 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	73		74
Fixed income securities [Member] | Corporate bonds [Member] | Fair value, inputs, Level 3 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	0		0
Private Equity Investments [Member] | Private Equity Investments [Member] | Total [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	50		46
Private Equity Investments [Member] | Private Equity Investments [Member] | Fair Value, Inputs, Level 1 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	0		0
Private Equity Investments [Member] | Private Equity Investments [Member] | Fair value, inputs, Level 2 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	0		0
Private Equity Investments [Member] | Private Equity Investments [Member] | Fair value, inputs, Level 3 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	50		46
Other Investments [Member] | Others [Member] | Total [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	23		28
Other Investments [Member] | Others [Member] | Fair Value, Inputs, Level 1 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	0		1
Other Investments [Member] | Others [Member] | Fair value, inputs, Level 2 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	23		27
Other Investments [Member] | Others [Member] | Fair value, inputs, Level 3 [Member]
FCX plans [Abstract]
Fair value of plan assets measurement	0		0
Pension plan [Member] | FCX [Member]
FCX plans [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	1,141		1,112		1,067
Pension plan [Member] | Investment In Subsidiary Pt Freeport Indonesia [Member]
FCX plans [Abstract]
Cash and Receivables In Plan Assets	56	[2]	49	[2]
Defined Benefit Plan, Fair Value of Plan Assets	107		97		78
Pension plan [Member] | Investment In Subsidiary Pt Freeport Indonesia [Member] | Total [Member] | Total [Member]
PT Freeport Indonesia plan [Abstract]
Fair value of plan assets measurement	51		48
Pension plan [Member] | Investment In Subsidiary Pt Freeport Indonesia [Member] | Total [Member] | Fair Value, Inputs, Level 1 [Member]
PT Freeport Indonesia plan [Abstract]
Fair value of plan assets measurement	51		48
Pension plan [Member] | Investment In Subsidiary Pt Freeport Indonesia [Member] | Total [Member] | Fair value, inputs, Level 2 [Member]
PT Freeport Indonesia plan [Abstract]
Fair value of plan assets measurement	0		0
Pension plan [Member] | Investment In Subsidiary Pt Freeport Indonesia [Member] | Total [Member] | Fair value, inputs, Level 3 [Member]
PT Freeport Indonesia plan [Abstract]
Fair value of plan assets measurement	0		0
Pension plan [Member] | Investment In Subsidiary Pt Freeport Indonesia [Member] | Equity securities [Member] | Common stocks [Member] | Total [Member]
PT Freeport Indonesia plan [Abstract]
Fair value of plan assets measurement	29		29
Pension plan [Member] | Investment In Subsidiary Pt Freeport Indonesia [Member] | Equity securities [Member] | Common stocks [Member] | Fair Value, Inputs, Level 1 [Member]
PT Freeport Indonesia plan [Abstract]
Fair value of plan assets measurement	29		29
Pension plan [Member] | Investment In Subsidiary Pt Freeport Indonesia [Member] | Equity securities [Member] | Common stocks [Member] | Fair value, inputs, Level 2 [Member]
PT Freeport Indonesia plan [Abstract]
Fair value of plan assets measurement	0		0
Pension plan [Member] | Investment In Subsidiary Pt Freeport Indonesia [Member] | Equity securities [Member] | Common stocks [Member] | Fair value, inputs, Level 3 [Member]
PT Freeport Indonesia plan [Abstract]
Fair value of plan assets measurement	0		0
Pension plan [Member] | Investment In Subsidiary Pt Freeport Indonesia [Member] | Fixed income securities [Member] | Government bonds [Member] | Total [Member]
PT Freeport Indonesia plan [Abstract]
Fair value of plan assets measurement	22		19
Pension plan [Member] | Investment In Subsidiary Pt Freeport Indonesia [Member] | Fixed income securities [Member] | Government bonds [Member] | Fair Value, Inputs, Level 1 [Member]
PT Freeport Indonesia plan [Abstract]
Fair value of plan assets measurement	22		19
Pension plan [Member] | Investment In Subsidiary Pt Freeport Indonesia [Member] | Fixed income securities [Member] | Government bonds [Member] | Fair value, inputs, Level 2 [Member]
PT Freeport Indonesia plan [Abstract]
Fair value of plan assets measurement	0		0
Pension plan [Member] | Investment In Subsidiary Pt Freeport Indonesia [Member] | Fixed income securities [Member] | Government bonds [Member] | Fair value, inputs, Level 3 [Member]
PT Freeport Indonesia plan [Abstract]
Fair value of plan assets measurement	$ 0		$ 0

[1] At the end of 2011, FCX reevaluated its level determinations, including those reported at December 31, 2010. While the majority of the underlying investments consists of publicly traded securities with actively quoted market values, the reported fair value of the investment vehicle containing these securities is based on net asset values that are not published publicly; therefore, FCX concluded these investments are more appropriately classified within Level 2 of the fair value hierarchy.

[2] Cash consists primarily of short-term time deposits.