Inventories, Including Long-Term Mill and Leach Stockpiles (Unaudited) (Details) - USD ($) $ in Millions		Mar. 31, 2016	Dec. 31, 2015
Components of Inventories [Line Items]
Total materials and supplies, net	[1]	$ 1,714	$ 1,869
Total mill and leach stockpiles		1,644	1,724
Raw materials (primarily concentrate)		247	220
Work-in-process		118	108
Finished goods		805	867
Total product inventories		1,170	1,195
Total long-term mill and leach stockpiles		2,324	2,271
Inventory obsolescence reserves		28	29
Current [Member]
Components of Inventories [Line Items]
Mill stockpiles		139	137
Leach stockpiles		1,505	1,587
Total mill and leach stockpiles		1,644	1,724
Long-Term [Member]
Components of Inventories [Line Items]
Mill stockpiles		521	480
Leach stockpiles		1,803	1,791
Total long-term mill and leach stockpiles	[2]	$ 2,324	$ 2,271

[1] Materials and supplies inventory was net of obsolescence reserves totaling $28 million at March 31, 2016, and $29 million at December 31, 2015.

[2] Estimated metals in stockpiles not expected to be recovered within the next 12 months.