Inventories

3 Months Ended

Mar. 31, 2019

Inventory Disclosure [Abstract]

Inventories

Inventories

	March 31, 2019		December 31, 2018
Finished goods	$	699	$	668
Work-in-process	1,448		1,371
Purchased raw materials	371		366
Operating supplies	94		87
Total inventories	$	2,612	$	2,492

At March 31, 2019 and December 31, 2018, the portion of inventories valued on a last-in, first-out (LIFO) basis was $1,340 and $1,292, respectively. If valued on an average-cost basis, total inventories would have been $527 and $530 higher at March 31, 2019 and December 31, 2018, respectively.