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

3 Months Ended

Mar. 31, 2019

Inventory Disclosure [Abstract]

Schedule of Inventory

The components of inventories follow (in millions):

	March 31, 2019		December 31, 2018
Current inventories:
Total materials and supplies, neta	$	1,595	$	1,528
Mill stockpiles	$	247	$	282
Leach stockpiles	1,127		1,171
Total current mill and leach stockpiles	$	1,374	$	1,453
Raw materials (primarily concentrate)	$	273	$	260
Work-in-process	137		192
Finished goods	1,082		1,326
Total product	$	1,492	$	1,778
Long-term inventories:
Mill stockpiles	$	265	$	265
Leach stockpiles	1,078		1,049
Total long-term mill and leach stockpilesb	$	1,343	$	1,314

a. Materials and supplies inventory was net of obsolescence reserves totaling $23 million at March 31, 2019, and $24 million at December 31, 2018.

b.

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