Inventories, Including Long-Term Mill and Leach Stockpiles (Unaudited) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015		Dec. 31, 2014
Components of Inventories [Line Items]
Raw materials (primarily concentrates)	$ 272		$ 288
Work-in-process	158		174
Finished goods	1,012		1,099
Total product inventories	1,442		1,561
Total mill and leach stockpiles	1,877		1,914
Total materials and supplies, net	1,919	[1]	1,886	[1]
Total long-term mill and leach stockpiles	2,261		2,179
Inventory obsolescence reserves	21		20
Current [Member]
Components of Inventories [Line Items]
Mill stockpiles	101		86
Leach stockpiles	1,776		1,828
Total mill and leach stockpiles	1,877		1,914
Long-Term [Member]
Components of Inventories [Line Items]
Mill stockpiles	346		360
Leach stockpiles	1,915		1,819
Total long-term mill and leach stockpiles	$ 2,261	[2]	$ 2,179	[2]

[1] Materials and supplies inventory was net of obsolescence reserves totaling $21 million at March 31, 2015, and $20 million at December 31, 2014.

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