Inventories

Inventories are stated at the lower of cost and net realizable value. In the United States, we manufacture certain finished products and parts inventories for drill bits, completion products, bulk materials and other tools that are recorded using the last-in, first-out method, which totaled $177 million at December 31, 2017 and $133 million at December 31, 2016. If the average cost method had been used, total inventories would have been $31 million higher than reported as of December 31, 2017 and $16 million higher as of December 31, 2016. The cost of the remaining inventory was recorded using the average cost method. Inventories consisted of the following:



	December 31
Millions of dollars	2017		2016
Finished products and parts	$	1,547	$	1,388
Raw materials and supplies	703		778
Work in process	146		109
Total	$	2,396	$	2,275

All amounts in the table above are reported net of obsolescence reserves of $276 million at December 31, 2017 and $263 million at December 31, 2016.