Inventories, Including Long-Term Mill and Leach Stockpiles (Unaudited) (Tables)

9 Months Ended

Sep. 30, 2016

Inventories, Including Long Term Mill and Leach Stockpiles [Abstract]

Schedule of Inventory [Table Text Block]

The components of inventories follow (in millions):

	September 30, 2016		December 31, 2015
Current inventories:
Total materials and supplies, neta	$	1,348	$	1,594
Mill stockpiles	$	172	$	137
Leach stockpiles	1,140		1,402
Total current mill and leach stockpiles	$	1,312	$	1,539
Raw materials (primarily concentrate)	$	209	$	220
Work-in-process	94		108
Finished goods	722		743
Total product inventories	$	1,025	$	1,071
Long-term inventories:
Mill stockpiles	$	580	$	480
Leach stockpiles	1,143		1,183
Total long-term mill and leach stockpilesb	$	1,723	$	1,663

a. Materials and supplies inventory was net of obsolescence reserves totaling $31 million at September 30, 2016, and $26 million at December 31, 2015.

b. Estimated metals in stockpiles not expected to be recovered within the next 12 months.