Financial Instruments (Unaudited) Oil and Gas (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015 MBbls		Dec. 31, 2014	Sep. 30, 2014
Derivative [Line Items]
Derivative Liability	$ 51		$ 99
Maximum Price Limit per Barrel				20
2015 Positions [Member] | Derivatives not designated as hedging instruments [Member] | Crude Oil Options [Member]
Derivative [Line Items]
Daily Volumes (Bbls)	23,000,000
2015 Positions [Member] | Derivatives not designated as hedging instruments [Member] | Crude Oil Options [Member] | 84 MBbls [Member]
Derivative [Line Items]
Daily Volumes (Bbls)	84	[1]
Derivative, Average Floor Price	90	[1],[2]
Derivative, Average Floor Price Limit	70	[1],[2]
Derivative, Underlying Basis	Brent	[1]
Weighted Average [Member] | Crude Oil Options [Member]
Derivative [Line Items]
Deferred Premium Price	6.89
Weighted Average [Member] | 2015 Positions [Member] | Derivatives not designated as hedging instruments [Member] | Crude Oil Options [Member] | 84 MBbls [Member]
Derivative [Line Items]
Deferred Premium Price	6.89	[1]

[1] If the index price is less than the per barrel floor, FCX receives the difference between the per barrel floor and the index price up to a maximum of $20 per barrel less the option premium. If the index price is at or above the per barrel floor, FCX pays the option premium and no cash settlement is received.

[2] The average strike prices do not reflect any premiums to purchase the put options.