CONTINGENCIES (Details) (USD $)	12 Months Ended
	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
Contingencies [Abstract]
Aggregate environmental capital expenditures and other environmental costs including joint venture partners' share	$ 387,000,000		$ 372,000,000		$ 289,000,000
Minimum number of active remediation projects in the United States (in number of projects)	100
Approximate number of states with active remediation projects (in number of states)	27
Summary of changes in environmental obligations [Roll Forward]
Balance at beginning of year	1,422,000,000		1,464,000,000		1,401,000,000
Accretion expense	88,000,000	[1]	97,000,000	[1]	102,000,000	[1]
Additions	132,000,000		19,000,000		40,000,000
Reductions	(68,000,000)		0		(3,000,000)
Spending	(121,000,000)		(158,000,000)		(76,000,000)
Balance at end of year	1,453,000,000		1,422,000,000		1,464,000,000
Less current portion	(205,000,000)		(138,000,000)		(168,000,000)
Long-term portion	1,248,000,000		1,284,000,000		1,296,000,000
Estimated environmental cash payments (on an undiscounted and unescalated basis) [Abstract]
2012	205,000,000
2013	130,000,000
2014	80,000,000
2015	76,000,000
2016	43,000,000
Thereafter	1,800,000,000
Recorded environmental obligations for most significant sites	1,200,000,000
Financial assurance obligations associated with closure and reclamation costs	899,000,000
Financial assurance obligations associated with closure and reclamation costs, in form of parent company guarantees and financial capability demonstrations	565,000,000
Trust assets, legally restricted to fund a portion of asset retirement obligations for Chino, Tyrone and Cobre	151,000,000		137,000,000
Letters of credit and bank guarantees	110,000,000
Total surety bonds	148,000,000
Amount of surety bonds associated with reclamation and closure	127,000,000
Amount of surety bonds associated with self-insurance bonds primarily for workers' compensation	19,000,000
Other surety bonds	2,000,000
Insurance reserves, total	58,000,000
Insurance reserves, current portion, included in accounts payable and accrued liabilities	8,000,000
Insurance reserves, long-term portion, included in other liabilities	50,000,000
Estimated Environmental Obligations on an Undiscounted and Unescalated Basis	2,300,000,000
Estimated environmental obligations discounted on Fair Value basis	1,500,000,000
Minimum range for environmental obligations (undiscounted and unescalated)	2,200,000,000
Maximum range for environmental obligations (undiscounted and unescalated)	$ 3,100,000,000

[1] Represents accretion of the fair value of environmental obligations assumed in the acquisition of FMC, which were determined on a discounted cash flow basis.