Inventories (Tables)

3 Months Ended

Mar. 31, 2018

Inventory Disclosure [Abstract]

Inventories

Inventories (principally using the last-in, first-out (LIFO) method) are comprised of the following:

(Millions of dollars)	March 31, 2018		December 31, 2017
Raw materials	$	3,179	$	2,802
Work-in-process	2,465		2,254
Finished goods	5,114		4,761
Supplies	189		201
Total inventories	$	10,947	$	10,018