Inventories

Inventories at September 30, 2017 and December 31, 2016 were as follows (in millions):



	September 30, 2017			December 31, 2016
Raw materials and supplies	$	157.4		$	149.6
Work-in-process	887.3			837.9
Finished goods	164.8			161.7
Total inventories at current cost	1,209.5			1,149.2
Adjustment from current cost to LIFO cost basis	45.8			97.3
Inventory valuation reserves	(118.7		)	(169.0		)
Progress payments	(35.5		)	(40.5		)
Total inventories, net	$	1,101.1		$	1,037.0

Inventories are stated at the lower of cost (LIFO, first-in, first-out (FIFO), and average cost methods) or market, less progress payments. Most of the Company’s inventory is valued utilizing the LIFO costing methodology. Inventory of the Company’s non-U.S. operations is valued using average cost or FIFO methods. Due to deflationary impacts primarily related to raw materials, the carrying value of the Company’s inventory as valued on LIFO exceeds current replacement cost, and based on a lower of cost or market value analysis, a net realizable value (NRV) inventory reserve is required. Impacts to cost of sales for changes in the LIFO costing methodology and associated NRV inventory reserves were as follows (in millions):



	Nine months ended September 30,
	2017			2016
LIFO benefit (charge)	$	(51.5	)	$	(23.1	)
NRV benefit (charge)	51.3			23.5
Net cost of sales impact	$	(0.2	)	$	0.4

The first nine months of 2016 results included $17.7 million in inventory valuation charges related to the market-based valuation of titanium products. Additionally, in the third quarter of 2016, in conjunction with the indefinite idling of the Company’s Rowley, UT titanium sponge facility, the Company recorded an additional $11.3 million charge to revalue titanium sponge inventory based on revised assessments of industrial grade titanium market conditions and expected utilization of this inventory.