Debt and Equity Transactions (Unaudited) Interests and Dividends (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010	Sep. 29, 2011
Debt and Equity Transactions [Abstract]
Interest costs incurred	$ 105,000,000	$ 126,000,000	$ 325,000,000	$ 409,000,000
Interest Costs, Capitalized During Period	27,000,000	23,000,000	75,000,000	39,000,000
Dividends Payable, Amount Per Share					$ 0.25
Dividends Payable, Date Declared, Day, Month and Year	Sep. 29, 2011
Dividends Payable, Date to be Paid, Day, Month and Year	Nov. 01, 2011
Dividends Payable, Date of Record, Day, Month and Year	Oct. 15, 2011
Mandatory Convertible Preferred Stock Dividend Rate Percentage (in hundredths)			6.75%
Comprehensive Income Attributable to FCX Common Stockholders	$ 1,100,000,000	$ 1,200,000,000	$ 3,900,000,000	$ 2,800,000,000