INVENTORIES

The majority of our inventories are for business-jet aircraft. Our inventories are stated at the lower of cost or net realizable value. Work in process represents largely labor, material and overhead costs associated with aircraft in the manufacturing process and is based primarily on the estimated average unit cost in a production lot. Raw materials are valued primarily on the first-in, first-out method. We record pre-owned aircraft acquired in connection with the sale of new aircraft at the lower of the trade-in value or the estimated net realizable value.

Inventories consisted of the following:



	July 1, 2018		December 31, 2017
Work in process	$	4,385	$	3,872
Raw materials	1,381		1,357
Finished goods	49		51
Pre-owned aircraft	75		23
Total inventories	$	5,890	$	5,303

The increase in total inventories during the six-month period ended July 1, 2018, was due primarily to the ramp-up in production of the new G500 and G600 aircraft programs in our Aerospace segment.