Contingencies and Commitments (Unaudited) Tax and Other Matters (Details) - PT Freeport Indonesia [Member] - Tax Authority, In Papau, Indonesia [Member] - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Relating to January 2016 through April 2016 [Member]
Loss Contingencies [Line Items]
Loss Contingency, Estimate of Possible Loss	$ 12	$ 20
Change in Loss Contingency, percent	40.00%
Relating to August 2015 through March 2018 [Member]
Loss Contingencies [Line Items]
Loss Contingency, Estimate of Possible Loss	$ 169
Relating to August 2015 through March 2018 [Member] | Penalties [Member]
Loss Contingencies [Line Items]
Loss Contingency, Estimate of Possible Loss	$ 85