Contingencies and Commitments (Unaudited) (Details) (PT Freeport Indonesia [Member], USD $) In Millions, unless otherwise specified	Mar. 31, 2013
Loss Contingencies [Line Items]
Disputed tax assessments paid	$ 190
Disputed tax assessments paid, long-term portion	148
Relating To 2008 [Member] | Tax Assessment [Member]
Loss Contingencies [Line Items]
Foreign government assessment in connection with alleged obligations	59
Relating To 2008 [Member] | Interest Assessment [Member]
Loss Contingencies [Line Items]
Foreign government assessment in connection with alleged obligations	$ 55