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

6 Months Ended

Jun. 30, 2018

Inventory Disclosure [Abstract]

Schedule of Inventory

The components of inventories follow (in millions):

	June 30, 2018		December 31, 2017
Current inventories:
Total materials and supplies, neta	$	1,404	$	1,305
Mill stockpiles	$	293	$	360
Leach stockpiles	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
Long-term inventories:
Mill stockpiles	$	288	$	300
Leach stockpiles	1,083		1,109
Total long-term mill and leach stockpiles	$	1,371	$	1,409

a. Materials and supplies inventory was net of obsolescence reserves totaling $25 million at June 30, 2018, and $29 million at December 31, 2017.