Inventories, Including Long-Term Mill and Leach Stockpiles (Unaudited) (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Components of Inventories [Line Items]
Total materials and supplies, net	$ 1,404	$ 1,305
Mill stockpiles, current	293	360
Leach stockpiles, current	1,142	1,062
Total current mill and leach stockpiles	1,435	1,422
Raw materials (primarily concentrate)	435	265
Work-in-process	179	154
Finished goods	723	747
Total product inventories	1,337	1,166
Mill stockpiles, noncurrent	288	300
Leach stockpiles, noncurrent	1,083	1,109
Total long-term mill and leach stockpiles	1,371	1,409
Inventory obsolescence reserves	$ 25	$ 29