DEBT (Details) (USD $)	3 Months Ended			12 Months Ended			3 Months Ended		12 Months Ended	1 Months Ended	12 Months Ended		1 Months Ended					1 Months Ended				1 Months Ended			1 Months Ended			1 Months Ended	12 Months Ended				12 Months Ended						1 Months Ended	12 Months Ended			1 Months Ended
	Mar. 31, 2012	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Mar. 31, 2012 Revolving Credit Facility [Member]	Mar. 31, 2011 Revolving Credit Facility [Member]	Dec. 31, 2012 Revolving Credit Facility [Member]	Feb. 28, 2012 Senior Notes [Member]	Dec. 31, 2011 Senior Notes [Member]	Dec. 31, 2007 Senior Notes [Member]	Mar. 31, 2007 Assumed Debt [Member]	Dec. 31, 2012 Other debt (including equipment capital leases and short-term borrowings) [Member]	Dec. 31, 2011 Other debt (including equipment capital leases and short-term borrowings) [Member]	Dec. 31, 2012 Revolving Credit Facility [Member]	Dec. 31, 2011 Revolving Credit Facility [Member]	Dec. 31, 2021 3.55% Senior Notes Due 2022 [Member] Senior Notes [Member]	Feb. 28, 2012 3.55% Senior Notes Due 2022 [Member] Senior Notes [Member]	Dec. 31, 2012 3.55% Senior Notes Due 2022 [Member] Senior Notes [Member]	Dec. 31, 2011 3.55% Senior Notes Due 2022 [Member] Senior Notes [Member]	Feb. 28, 2012 1.40% Senior Notes Due 2015 [Member] Senior Notes [Member]	Dec. 31, 2012 1.40% Senior Notes Due 2015 [Member] Senior Notes [Member]	Dec. 31, 2011 1.40% Senior Notes Due 2015 [Member] Senior Notes [Member]	Feb. 28, 2012 2.15% Senior Notes Due 2017 [Member] Senior Notes [Member]	Dec. 31, 2012 2.15% Senior Notes Due 2017 [Member] Senior Notes [Member]	Dec. 31, 2011 2.15% Senior Notes Due 2017 [Member] Senior Notes [Member]	Mar. 31, 2012 Senior Notes Due 2017 [Member] Senior Notes [Member]	Dec. 31, 2012 Senior Notes Due 2017 [Member] Senior Notes [Member]	Dec. 31, 2011 Senior Notes Due 2017 [Member] Senior Notes [Member]	Sep. 30, 2012 Senior Notes Due 2017 [Member] Senior Notes [Member]	Mar. 31, 2007 Senior Notes Due 2017 [Member] Senior Notes [Member]	Dec. 31, 2012 9.5% Senior Notes due 2031 [Member] Assumed Debt [Member]	Dec. 31, 2011 9.5% Senior Notes due 2031 [Member] Assumed Debt [Member]	Dec. 31, 2012 6.125% Senior Notes due 2034 [Member] Assumed Debt [Member]	Dec. 31, 2011 6.125% Senior Notes due 2034 [Member] Assumed Debt [Member]	Dec. 31, 2012 7.125% Debentures due 2027 [Member] Assumed Debt [Member]	Dec. 31, 2011 7.125% Debentures due 2027 [Member] Assumed Debt [Member]	Apr. 30, 2012 8.25% Senior Notes due 2015 [Member] Senior Notes [Member]	Dec. 31, 2012 8.25% Senior Notes due 2015 [Member] Senior Notes [Member]	Dec. 31, 2011 8.25% Senior Notes due 2015 [Member] Senior Notes [Member]	Mar. 31, 2007 8.25% Senior Notes due 2015 [Member] Senior Notes [Member]	Apr. 30, 2010 Senior Floating Rates Notes Due 2015 [Member] Senior Notes [Member]	Mar. 31, 2007 Senior Floating Rates Notes Due 2015 [Member] Senior Notes [Member]
Debt Instruments [Line Items]
Debt Instrument, Issuance Date								Mar. 30, 2011
Long-term Debt, Gross				$ 3,527,000,000	$ 3,537,000,000									$ 172,000,000	$ 165,000,000	$ 0	$ 0			$ 1,995,000,000	$ 0		$ 500,000,000	$ 0		$ 500,000,000	$ 0		$ 0	$ 3,011,000,000			$ 130,000,000	$ 131,000,000	$ 115,000,000	$ 115,000,000	$ 115,000,000	$ 115,000,000
Less current portion of long-term debt and short-term borrownings				(2,000,000)	(4,000,000)
Long-term debt				3,525,000,000	3,533,000,000
Debt Instrument Maturity Date									Mar. 19, 2012
Loss On Extinguishment Of Debt, Gross				168,000,000	68,000,000	81,000,000	7,000,000				55,000,000																		168,000,000				6,000,000	4,000,000						55,000,000			22,000,000
Extinguishment of Debt, Gain (Loss), Net of Tax	149,000,000	(54,000,000)	(6,000,000)	149,000,000	(60,000,000)		(6,000,000)				(48,000,000)																		(149,000,000)				(5,000,000)	(3,000,000)						(49,000,000)			(20,000,000)
Revolving Credit Facility, Expiration Date									Mar. 30, 2016
Revolving Credit Facility, Maximum Borrowing Capacity									1,500,000,000
Amount of revolving credit facility available to PT Freeport Indonesia									500,000,000
Line of Credit Facility, Amount Outstanding									0
Letters of Credit Outstanding, Amount									43,000,000
Revolving Credit Facility, Remaining Borrowing Capacity									1,500,000,000
Remaining borrowing capacity available for letters of credit at period end									957,000,000
Debt Instrument, Description of Variable Rate Basis									London Interbank Offered Rate
Debt Instrument, Basis Spread on Variable Rate									1.75%
Face amount of senior notes sold																			2,000,000,000			500,000,000			500,000,000							3,500,000,000										1,500,000,000		1,000,000,000
Debt Instrument, Interest Rate, Stated Percentage																			3.55%			1.40%			2.15%				8.375%		8.375%		9.50%		6.125%		7.125%			8.25%
Proceeds from Issuance of Long-term Debt										2,970,000,000
Debt Instrument, Semi-Annual Interest Payment Dates																			March 1 and September 1			February 13 and August 13			March 1 and September 1
Net proceeds from sale of senior notes												5,900,000,000
Early Repayment Of Senior Debt																														358,000,000			49,000,000	26,000,000							237,000,000
Debt Instrument Face Amount At Retirement																												3,000,000,000		329,000,000			35,000,000	18,000,000					1,100,000,000		218,000,000		1,000,000,000
Debt Instrument, Redemption Date																												Mar. 14, 2012											Apr. 01, 2011				Apr. 01, 2010
Redemption price percentage to principal amount																		100.00%										104.553%											104.125%				101.00%
Amount of assumed debt													462,000,000
Fair value increase (decrease) of assumed debt													32,000,000
Debt instrument carrying amount																																	346,000,000
Long-term Debt, by Maturity [Abstract]
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months				2,000,000
Long-term Debt, Maturities, Repayments of Principal in Year Three				500,000,000
Long-term Debt, Maturities, Repayments of Principal in Year Five				500,000,000
Long-term Debt, Maturities, Repayments of Principal after Year Five				$ 2,525,000,000