22. Segments

Nucor reports its results in the following segments: steel mills, steel products and raw materials. The steel mills segment includes carbon and alloy steel in sheet, bars, structural and plate; steel foundation distributors; tubular products businesses; steel trading businesses; rebar distribution businesses; and Nucor’s equity method investments in Duferdofin Nucor and NuMit. The steel products segment includes steel joists and joist girders, steel deck, fabricated concrete reinforcing steel, cold finished steel, steel fasteners, metal building systems, steel grating, and wire and wire mesh. The raw materials segment includes The David J. Joseph Company and its affiliates, primarily a scrap broker and processor; Nu-Iron Unlimited and Nucor Steel Louisiana, two facilities that produce DRI used by the steel mills; our natural gas production operations; and Nucor’s equity method investment in Hunter Ridge. Nucor sold its 50% interest in Hunter Ridge during the third quarter of 2016. The steel mills, steel products and raw materials segments are consistent with the way Nucor manages its business, which is primarily based upon the similarity of the types of products produced and sold by each segment.

Net interest expense, other income, profit sharing expense and stock-based compensation are shown under Corporate/eliminations. Corporate assets primarily include cash and cash equivalents, short-term investments, allowances to eliminate intercompany profit in inventory, deferred income tax assets, federal and state income taxes receivable and investments in and advances to affiliates.

Nucor’s results by segment are as follows (in thousands):


	Year Ended December 31,
	2017			2016			2015
Net sales to external customers:
Steel mills	$	14,508,847		$	11,312,048		$	11,084,331
Steel products		4,000,606			3,687,448			3,966,895
Raw materials		1,742,940			1,208,626			1,388,050

	$	20,252,393		$	16,208,122		$	16,439,276

Intercompany sales:
Steel mills	$	2,925,321		$	2,070,077		$	2,152,157
Steel products		108,945			106,838			90,969
Raw materials		9,191,081			5,997,498			6,279,316
Corporate/eliminations		(12,225,347	)		(8,174,413	)		(8,522,442	)

	$	—		$	—		$	—

Depreciation expense:
Steel mills	$	414,670		$	377,627		$	381,352
Steel products		39,532			36,906			39,512
Raw materials		172,699			191,466			198,705
Corporate		8,932			7,193			6,188

	$	635,833		$	613,192		$	625,757

Amortization expense:
Steel mills	$	41,478		$	22,479		$	18,789
Steel products		20,825			21,998			23,932
Raw materials		28,925			29,385			31,539

	$	91,228		$	73,862		$	74,260

Earnings (loss) before income taxes and noncontrolling interests:
Steel mills	$	2,084,203		$	1,724,168		$	629,256
Steel products		206,805			249,970			276,048
Raw materials		129,296			(95,121	)		(283,938	)
Corporate/eliminations		(670,347	)		(580,358	)		(379,500	)

	$	1,749,957		$	1,298,659		$	241,866

Segment assets:
Steel mills	$	9,249,926		$	8,084,773		$	7,318,169
Steel products		2,737,486			2,544,344			2,485,122
Raw materials		3,396,110			3,235,237			3,123,190
Corporate/eliminations		457,736			1,359,164			1,400,488

	$	15,841,258		$	15,223,518		$	14,326,969

Capital expenditures:
Steel mills	$	359,215		$	375,996		$	248,532
Steel products		68,497			30,698			41,291
Raw materials		59,036			194,112			74,607
Corporate		20,326			16,871			338

	$	507,074		$	617,677		$	364,768

Net sales by product were as follows (in thousands). Further product group breakdown is impracticable.


	Year Ended December 31,
	2017		2016		2015
Net sales to external customers:
Sheet	$	6,407,974	$	5,178,467	$	4,628,805
Bar		3,558,806		2,886,648		3,005,450
Structural		1,979,898		1,982,642		2,137,413
Plate		1,644,934		1,204,185		1,312,663
Tubular products		917,235		60,106		—
Steel products		4,000,606		3,687,448		3,966,895
Raw materials		1,742,940		1,208,626		1,388,050

	$	20,252,393	$	16,208,122	$	16,439,276