Nucor (NUE) 10-Q 9 Aug 17 2017 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information	6 Months Ended
	Jul. 01, 2017shares
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jul. 1, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q2
Trading Symbol	NUE
Entity Registrant Name	NUCOR CORP
Entity Central Index Key	73,309
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding	319,425,944

Condensed Consolidated Statemen

Condensed Consolidated Statements of Earnings - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 01, 2017	Jul. 02, 2016	Jul. 01, 2017	Jul. 02, 2016
Income Statement [Abstract]
Net sales	$ 5,174,769	$ 4,245,772	$ 9,989,948	$ 7,961,348
Costs, expenses and other:
Cost of products sold	4,465,144	3,660,512	8,520,073	7,061,103
Marketing, administrative and other expenses	170,211	161,711	346,637	271,456
Equity in earnings of unconsolidated affiliates	(13,302)	(6,819)	(22,058)	(16,064)
Interest expense, net	44,580	40,484	88,185	85,406
Costs, expenses and other, total	4,666,633	3,855,888	8,932,837	7,401,901
Earnings before income taxes and noncontrolling interests	508,136	389,884	1,057,111	559,447
Provision for income taxes	166,412	118,515	337,739	165,581
Net earnings	341,724	271,369	719,372	393,866
Earnings attributable to noncontrolling interests	18,676	27,749	39,425	62,681
Net earnings attributable to Nucor stockholders	$ 323,048	$ 243,620	$ 679,947	$ 331,185
Net earnings per share:
Basic	$ 1	$ 0.76	$ 2.12	$ 1.03
Diluted	$ 1	$ 0.76	$ 2.11	$ 1.03
Average shares outstanding:
Basic	320,439	319,360	320,332	319,299
Diluted	321,226	319,583	321,186	319,437
Dividends declared per share	$ 0.3775	$ 0.3750	$ 0.7550	$ 0.7500

Condensed Consolidated Stateme3

Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 01, 2017	Jul. 02, 2016	Jul. 01, 2017	Jul. 02, 2016
Statement Of Comprehensive Income [Abstract]
Net earnings	$ 341,724	$ 271,369	$ 719,372	$ 393,866
Other comprehensive income:
Net unrealized (loss) income on hedging derivatives, net of income taxes of $0 and $1,900 for the second quarter of 2017 and 2016, respectively, and ($1,000) and $900 for the first six months of 2017 and 2016, respectively	(71)	3,243	(1,706)	1,512
Reclassification adjustment for loss on settlement of hedging derivatives included in net income, net of income taxes of $0 and $1,900 for the second quarter of 2017 and 2016, respectively, and $300 and $3,600 for the first six months of 2017 and 2016, respectively	171	3,257	656	6,288
Foreign currency translation gain, net of income taxes of $0 for the second quarter of 2017 and 2016, and $0 for the first six months of 2017 and 2016	23,957	8,287	25,958	62,184
Net current-period other comprehensive income (loss)	24,057	14,787	24,908	69,984
Comprehensive income	365,781	286,156	744,280	463,850
Comprehensive income attributable to noncontrolling interests	(18,676)	(27,749)	(39,425)	(62,681)
Comprehensive income attributable to Nucor stockholders	$ 347,105	$ 258,407	$ 704,855	$ 401,169

Condensed Consolidated Stateme4

Condensed Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 01, 2017	Jul. 02, 2016	Jul. 01, 2017	Jul. 02, 2016
Statement Of Comprehensive Income [Abstract]
Net unrealized (loss) income on hedging derivatives, tax	$ 0	$ 1,900	$ (1,000)	$ 900
Reclassification adjustment for loss on settlement of hedging derivatives included in net income, tax effect	0	1,900	300	3,600
Foreign currency translation gain tax	$ 0	$ 0	$ 0	$ 0

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jul. 01, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 1,511,353	$ 2,045,961
Short-term investments	50,000	150,000
Accounts receivable, net	2,081,150	1,631,676
Inventories, net	3,326,563	2,479,958
Other current assets	213,626	198,798
Total current assets	7,182,692	6,506,393
Property, plant and equipment, net	5,062,423	5,078,650
Goodwill	2,179,641	2,052,728
Other intangible assets, net	946,978	866,835
Other assets	740,991	718,912
Total assets	16,112,725	15,223,518
Current liabilities:
Short-term debt	39,197	17,959
Long-term debt due within one year	1,100,000	600,000
Accounts payable	1,214,313	838,109
Salaries, wages and related accruals	422,744	428,829
Accrued expenses and other current liabilities	549,052	505,069
Total current liabilities	3,325,306	2,389,966
Long-term debt due after one year	3,240,694	3,739,141
Deferred credits and other liabilities	834,812	839,703
Total liabilities	7,400,812	6,968,810
Nucor stockholders' equity:
Common stock	151,920	151,734
Additional paid-in capital	2,004,079	1,974,672
Retained earnings	8,067,846	7,630,916
Accumulated other comprehensive loss, net of income taxes	(292,935)	(317,843)
Treasury stock	(1,553,845)	(1,559,614)
Total Nucor stockholders' equity	8,377,065	7,879,865
Noncontrolling interests	334,848	374,843
Total equity	8,711,913	8,254,708
Total liabilities and equity	$ 16,112,725	$ 15,223,518

Condensed Consolidated Stateme6

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jul. 01, 2017	Jul. 02, 2016
Operating activities:
Net earnings	$ 719,372	$ 393,866
Adjustments:
Depreciation	318,278	306,088
Amortization	45,443	35,587
Stock-based compensation	41,159	37,576
Deferred income taxes	(4,173)	11,687
Distributions from affiliates	46,877	37,026
Equity in earnings of unconsolidated affiliates	(22,058)	(16,064)
Changes in assets and liabilities (exclusive of acquisitions and dispositions):
Accounts receivable	(396,452)	(398,266)
Inventories	(781,581)	(183,056)
Accounts payable	371,158	452,815
Federal income taxes	(14,114)	129,325
Salaries, wages and related accruals	(5,794)	32,091
Other operating activities	28,849	27,697
Cash provided by operating activities	346,964	866,372
Investing activities:
Capital expenditures	(189,235)	(227,342)
Investment in and advances to affiliates	(19,000)	(12,508)
Disposition of plant and equipment	12,509	11,631
Acquisitions (net of cash acquired)	(478,410)
Purchases of investments	(50,000)	(550,000)
Proceeds from the sale of investments	150,000	100,000
Other investing activities	(990)	6,265
Cash used in investing activities	(575,126)	(671,954)
Financing activities:
Net change in short-term debt	21,235	(31,375)
Issuance of common stock	7,432	1,882
Payment of tax withholdings on certain stock-based compensation	(13,185)	(9,407)
Excess tax benefits from stock-based compensation		916
Distributions to noncontrolling interests	(79,420)	(78,684)
Cash dividends	(242,704)	(240,302)
Acquisition of treasury stock		(5,173)
Other financing activities	(1,101)	(4,630)
Cash used in financing activities	(307,743)	(366,773)
Effect of exchange rate changes on cash	1,297	14,036
Decrease in cash and cash equivalents	(534,608)	(158,319)
Cash and cash equivalents - beginning of year	2,045,961	1,939,469
Cash and cash equivalents - end of six months	1,511,353	1,781,150
Non-cash investing activity:
Change in accrued plant and equipment purchases	$ (12,927)	$ 2,630

Basis of Interim Presentation

Basis of Interim Presentation	6 Months Ended
	Jul. 01, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Interim Presentation	1. BASIS OF INTERIM PRESENTATION: The information included in this Item 1 reflects all adjustments which are, in the opinion of management, necessary to a fair statement of the results for the interim periods presented and are of a normal and recurring nature unless otherwise noted. The information furnished has not been audited; however, the December 31, 2016 condensed consolidated balance sheet data was derived from audited financial statements but does not include all disclosures required by accounting principles generally accepted in the United States of America. The unaudited condensed consolidated financial statements in this Item 1 should be read in conjunction with the audited consolidated financial statements and the notes thereto included in Nucor’s Annual Report on Form 10-K Recently Adopted Accounting Pronouncements – In the first quarter of 2017, Nucor adopted new accounting guidance that amends the accounting for employee share-based payment transactions. This new standard requires income statement recognition of all tax effects, including all excess tax benefits and tax deficiencies, resulting from the settlement of share-based awards in the reporting period in which they occur. The standard also requires that all tax-related In January 2017, new guidance was issued regarding the simplification of the test for goodwill impairment. The new guidance eliminates Step 2 from the goodwill impairment test and will require an entity to perform its annual, or interim, goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount. The new guidance is effective for the Company for annual and interim reporting periods beginning after December 15, 2019, with early adoption permitted. The Company early adopted this new guidance in the first quarter of 2017. The adoption of this new guidance did not have a material impact on the Company’s consolidated financial statements. Recently Issued Accounting Pronouncements - In May 2014, new accounting guidance was issued that will supersede nearly all existing accounting guidance related to revenue recognition. The new guidance provides that an entity recognizes revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. This update also requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts, including significant judgments and changes in judgments, and assets recognized from costs incurred to obtain or fulfill a contract. The Financial Accounting Standards Board has also issued a number of updates to this new accounting guidance. The standard is effective for the Company for annual and interim reporting periods beginning after December 15, 2017 and is not expected to have a material effect on the Company’s consolidated financial statements. In January 2016, new accounting guidance was issued regarding the recognition and measurement of financial assets and financial liabilities. Changes to the current accounting guidance primarily affect the accounting for equity investments, financial liabilities under the fair value option, and the presentation and disclosure requirements for financial instruments. In addition, the Financial Accounting Standards Board clarified guidance related to the valuation allowance assessment when recognizing deferred tax assets resulting from unrealized losses on available-for-sale In February 2016, new accounting guidance was issued regarding the accounting for leases. The new guidance requires all lessees to recognize on the balance sheet right to use assets and lease liabilities for the rights and obligations created by lease arrangements with terms greater than 12 months. The standard is effective for the Company for annual and interim reporting periods beginning after December 15, 2018. The Company is evaluating the impact that the adoption of this new guidance will have on its consolidated financial statements, but we expect that assets and liabilities will increase on the consolidated balance sheet. In August 2016, new accounting guidance was issued regarding the presentation and classification of certain cash receipts and cash payments in the statement of cash flows. The new guidance addresses specific cash flow presentation issues in order to reduce diversity in existing practice. The new guidance is effective for the Company for annual and interim reporting periods beginning after December 15, 2017. The Company is evaluating the impact that the adoption of this new guidance will have on its consolidated financial statements. In October 2016, new accounting guidance was issued regarding intra-entity transfers of assets other than inventory. The new guidance requires that an entity should recognize the income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs. The new guidance is effective for the Company for annual and interim reporting periods beginning after December 15, 2017. The Company is evaluating the impact that the adoption of this new guidance will have on its consolidated financial statements. Prior Year Change in Accounting Principle - In the fourth quarter of 2016, the Company changed its accounting method for valuing its inventories held by the parent company and Nucor-Yamato Steel Company to the first-in, first-out last-in, first-out The effects of the change in accounting principle from LIFO to FIFO have been retrospectively applied to all periods presented. As a result of the retrospective application of the change in accounting principle, certain financial statement line items in the Company’s condensed consolidated statements of earnings for the three- and six-month six-month (in thousands, except per share data) As Originally Reported Effect of Change As Currently Reported Condensed Consolidated Statement of Earnings for the Three Months (13 Weeks) Ended July 2, 2016: Cost of products sold $ 3,679,512 $ (19,000 ) $ 3,660,512 Provision for income taxes 112,548 5,967 118,515 Net earnings 258,336 13,033 271,369 Earnings attributable to noncontrolling interests 24,564 3,185 27,749 Net earnings attributable to Nucor stockholders 233,772 9,848 243,620 Net earnings per share: Basic $ 0.73 $ 0.03 $ 0.76 Diluted $ 0.73 $ 0.03 $ 0.76 (in thousands, except per share data) As Originally Reported Effect of Change As Currently Reported Condensed Consolidated Statement of Earnings for the Six Months (26 Weeks) Ended July 2, 2016: Cost of products sold $ 7,108,140 $ (47,037 ) $ 7,061,103 Provision for income taxes 149,613 15,968 165,581 Net earnings 362,797 31,069 393,866 Earnings attributable to noncontrolling interests 58,271 4,410 62,681 Net earnings attributable to Nucor stockholders 304,526 26,659 331,185 Net earnings per share: Basic $ 0.95 $ 0.08 $ 1.03 Diluted $ 0.95 $ 0.08 $ 1.03 (in thousands) Condensed Consolidated Statement of Cash Flows for the Six Months (26 Weeks) Ended July 2, 2016: Net earnings $ 362,797 $ 31,069 $ 393,866 Changes in inventories (136,019 ) (47,037 ) (183,056 ) Changes in deferred income taxes (4,281 ) 15,968 11,687

Acquisitions and Dispositions

Acquisitions and Dispositions	6 Months Ended
	Jul. 01, 2017
Business Combinations [Abstract]
Acquisitions and Dispositions	2. ACQUISITIONS AND DISPOSITIONS: On January 20, 2017, Nucor used cash on hand to acquire Republic Conduit (Republic) for a purchase price of $331.6 million. Republic produces steel electrical conduit primarily used to protect and route electrical wiring in various nonresidential structures such as hospitals, office buildings and stadiums. With its two facilities located in Kentucky and Georgia, Republic’s annual shipment volume has averaged 146,000 tons during the past two years. This acquisition not only further expands Nucor’s product portfolio to include steel electrical conduit but the Company also believes it will be an important, value-added channel to market for Nucor’s sheet mills. Republic’s financial results are included as part of the steel mills segment (see Note 18). We have allocated the purchase price for Republic to its individual assets acquired and liabilities assumed. While the purchase price allocation is substantially complete, it is still preliminary and subject to change. The following table summarizes the fair values of the assets acquired and liabilities assumed of Republic as of the date of acquisition (in thousands): Cash $ 206 Accounts receivable 39,177 Inventory 33,561 Other current assets 1,101 Property, plant and equipment 67,412 Goodwill 115,562 Other intangible assets 89,200 Other assets 3,118 Total assets acquired 349,337 Current liabilities 17,743 Total liabilities assumed 17,743 Net assets acquired $ 331,594 The following table summarizes the purchase price allocation to the identifiable intangible assets of Republic as of the date of acquisition (in thousands, except years): Weighted - Customer relationships $ 80,800 12 years Trademarks and trade names 8,400 13 years $ 89,200 The goodwill of $115.6 million is calculated as the excess of the purchase price over the fair values of the assets acquired and liabilities assumed and has been allocated to the steel mills segment (see Note 6). Goodwill recognized for tax purposes was $118.6 million, all of which is deductible for tax purposes. Other acquisitions, exclusive of purchase price adjustments of acquisitions made and net of cash acquired, totaled $150.8 million in the first six months of 2017 (none in the first six months of 2016). Included in the 2017 amount is the January 9, 2017 acquisition of Southland Tube (Southland). Nucor used cash on hand to acquire Southland for a purchase price of approximately $130 million. Southland is a manufacturer of hollow structural section tubing, which is primarily used in nonresidential construction markets. Southland had shipments of approximately 240,000 tons in 2016 and has one manufacturing facility in Birmingham, Alabama.

Accounts Receivable

Accounts Receivable	6 Months Ended
	Jul. 01, 2017
Receivables [Abstract]
Accounts Receivable	3. ACCOUNTS RECEIVABLE: An allowance for doubtful accounts is maintained for estimated losses resulting from the inability of our customers to make required payments. Accounts receivable are stated net of an allowance for doubtful accounts of $47.3 million at July 1, 2017 ($45.9 million at December 31, 2016).

Inventories

Inventories	6 Months Ended
	Jul. 01, 2017
Inventory Disclosure [Abstract]
Inventories	4. INVENTORIES: Inventories consisted of approximately 39% raw materials and supplies and 61% finished and semi-finished products at July 1, 2017 (37% and 63%, respectively, at December 31, 2016). Nucor’s manufacturing process consists of a continuous, vertically integrated process from which products are sold to customers at various stages throughout the process. Since most steel products can be classified as either finished or semi-finished products, these two categories of inventory are combined. Use of the lower of cost or market methodology reduced inventories by $2.0 million at July 1, 2017 ($2.2 million at December 31, 2016).

Property, Plant and Equipment

Property, Plant and Equipment	6 Months Ended
	Jul. 01, 2017
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	5. PROPERTY, PLANT AND EQUIPMENT: Property, plant and equipment is recorded net of accumulated depreciation of $8.46 billion at July 1, 2017 ($8.16 billion at December 31, 2016). Given the natural gas pricing environment, Nucor performed an impairment assessment of its proved producing natural gas well assets in December 2016. One of the main assumptions that most significantly affects the undiscounted cash flows determination is management’s estimate of future natural gas prices. The pricing used in this impairment assessment was developed by management based on projected natural gas market supply and demand dynamics, in conjunction with a review of projections by numerous sources of market data. This analysis was performed on each of Nucor’s three groups of wells, with each group defined by common geographic location. Each of Nucor’s three groups of wells passed the impairment test. One of the groups of wells had estimated undiscounted cash flows that were noticeably closer to its carrying value of $80.8 million as of December 31, 2016. The carrying value of that group of wells was $75.8 million at July 1, 2017. Changes in the natural gas industry or a prolonged low price environment beyond what had already been assumed in the analysis could cause management to revise the natural gas price assumptions, which could possibly result in an impairment of some or all of the groups of proved well assets.

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	6 Months Ended
	Jul. 01, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangible Assets	6. GOODWILL AND OTHER INTANGIBLE ASSETS: The change in the net carrying amount of goodwill for the six months ended July 1, 2017, by segment is as follows (in thousands): Steel Mills Steel Products Raw Materials Total Balance at December 31, 2016 $ 620,156 $ 702,995 $ 729,577 $ 2,052,728 Acquisitions 125,328 — — 125,328 Translation — 1,585 — 1,585 Balance at July 1, 2017 $ 745,484 $ 704,580 $ 729,577 $ 2,179,641 Nucor completed its most recent annual goodwill impairment testing during the fourth quarter of 2016 and concluded that there was no impairment of goodwill for any of its reporting units. There have been no triggering events requiring an interim assessment for impairment since the most recent annual impairment testing date. Intangible assets with estimated useful lives of 5 to 22 years are amortized on a straight-line or accelerated basis and are comprised of the following (in thousands): July 1, 2017 December 31, 2016 Gross Accumulated Gross Accumulated Customer relationships $ 1,409,125 $ 603,734 $ 1,295,803 $ 566,884 Trademarks and trade names 174,116 71,843 161,851 66,494 Other 62,807 23,493 62,807 20,248 $ 1,646,048 $ 699,070 $ 1,520,461 $ 653,626 Intangible asset amortization expense in the second quarter of 2017 and 2016 was $23.0 million and $17.5 million, respectively, and was $45.4 million and $35.6 million in the first six months of 2017 and 2016, respectively. Annual amortization expense is estimated to be $90.8 million in 2017; $88.8 million in 2018; $85.9 million in 2019; $83.5 million in 2020; and $82.3 million in 2021.

Equity Investments

Equity Investments	6 Months Ended
	Jul. 01, 2017
Equity Method Investments and Joint Ventures [Abstract]
Equity Investments	7. EQUITY INVESTMENTS: The carrying value of our equity investments in domestic and foreign companies was $679.5 million at July 1, 2017 ($663.4 million at December 31, 2016) and is recorded in other assets in the condensed consolidated balance sheets. NUMIT Nucor has a 50% economic and voting interest in NuMit LLC (NuMit). NuMit owns 100% of the equity interest in Steel Technologies LLC, an operator of 25 sheet processing facilities located throughout the United States, Canada and Mexico. Nucor accounts for the investment in NuMit (on a one-month DUFERDOFIN NUCOR Nucor owns a 50% economic and voting interest in Duferdofin Nucor S.r.l. (Duferdofin Nucor), an Italian steel manufacturer, and accounts for the investment (on a one-month Nucor’s investment in Duferdofin Nucor at July 1, 2017 was $274.7 million ($256.6 million at December 31, 2016). Nucor’s 50% share of the total net assets of Duferdofin Nucor was $110.3 million at July 1, 2017, resulting in a basis difference of $164.4 million due to the step-up step-up As of July 1, 2017, Nucor had outstanding notes receivable of €35.0 million ($40.0 million) from Duferdofin Nucor (€35.0 million, or $36.9 million, as of December 31, 2016). The notes receivable bear interest at 0.94% and reset annually on September 30 to the 12-month Nucor has issued a guarantee, the fair value of which is immaterial, for its ownership percentage (50%) of Duferdofin Nucor’s borrowings under Facility A of a Structured Trade Finance Facilities Agreement (Facility A). The maximum amount Duferdofin Nucor could have borrowed under Facility A was €122.5 million ($139.9 million) as of July 1, 2017. As of July 1, 2017, there was €115.0 million ($131.4 million) outstanding under that facility (€107.0 million, or $112.7 million, as of December 31, 2016). Facility A was amended in 2015 to extend the maturity date to October 12, 2018. If Duferdofin Nucor fails to pay when due any amounts for which it is obligated under Facility A, Nucor could be required to pay 50% of such amounts pursuant to and in accordance with the terms of its guarantee. Any indebtedness of Duferdofin Nucor to Nucor is effectively subordinated to the indebtedness of Duferdofin Nucor under Facility A. Nucor has not recorded any liability associated with this guarantee. ALL EQUITY INVESTMENTS Nucor reviews its equity investments for impairment if and when circumstances indicate that a decline in value below their carrying amounts may have occurred. Nucor last assessed its equity investment in Duferdofin Nucor for impairment in 2015 due to the protracted challenging steel market conditions caused by excess global overcapacity, which increased in 2015, and the difficult economic environment in Europe. After completing its assessment, the Company determined that the carrying amount exceeded its estimated fair value and incurred a partial impairment of its investment. While the operating performance of Duferdofin Nucor showed meaningful improvement in 2016 and the first half of 2017, steel market conditions in Europe have continued to be challenging. Therefore, it is reasonably possible that material deviation of future performance from the estimates used in our most recent valuation could result in further impairment of our investment in Duferdofin Nucor. We will continue to monitor for potential triggering events that could affect the carrying value of our investment in Duferdofin Nucor as a result of future market conditions and any changes in our business strategy.

Current Liabilities

Current Liabilities	6 Months Ended
	Jul. 01, 2017
Payables and Accruals [Abstract]
Current Liabilities	8. CURRENT LIABILITIES: Book overdrafts, included in accounts payable in the condensed consolidated balance sheets, were $123.5 million at July 1, 2017 ($61.3 million at December 31, 2016). Dividends payable, included in accrued expenses and other current liabilities in the condensed consolidated balance sheets, were $121.6 million at July 1, 2017 ($121.3 million at December 31, 2016).

Derivatives

Derivatives	6 Months Ended
	Jul. 01, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives	9. DERIVATIVES: Nucor periodically uses derivative financial instruments primarily to partially manage its exposure to price risk related to natural gas purchases used in the production process as well as to scrap, copper and aluminum purchased for resale to its customers. In addition, Nucor periodically uses derivatives to partially manage its exposure to changes in interest rates on outstanding debt instruments and uses forward foreign exchange contracts to hedge cash flows associated with certain assets and liabilities, firm commitments and anticipated transactions. Nucor recognizes all derivative instruments in the condensed consolidated balance sheets at fair value. Any resulting changes in fair value are recorded as adjustments to other comprehensive income (loss), net of tax, or recognized in net earnings, as appropriate. At July 1, 2017, natural gas swaps covering approximately 17.6 million MMBTUs (extending through December 2019) were outstanding. The following tables summarize information regarding Nucor’s derivative instruments (in thousands): Fair Value of Derivative Instruments Fair Value at Balance Sheet Location July 1, 2017 Dec. 31, 2016 Asset derivatives designated as hedging instruments: Commodity contracts Other current assets $ 200 $ 1,250 Asset derivatives not designated as hedging instruments: Foreign exchange contracts Other current assets — 779 Total asset derivatives $ 200 $ 2,029 Liability derivatives designated as hedging instruments: Commodity contracts Deferred credits and other liabilities $ (700 ) $ — Liability derivatives not designated as hedging instruments: Commodity contracts Accrued expenses and other current liabilities (658 ) (605 ) Foreign exchange contracts Accrued expenses and other current liabilities (1,232 ) — Total liability derivatives not designated as hedging instruments (1,890 ) (605 ) Total liability derivatives $ (2,590 ) $ (605 ) The Effect of Derivative Instruments on the Condensed Consolidated Statements of Earnings Derivatives Designated as Hedging Instruments Amount of Gain or (Loss), net of Amount of Gain or (Loss), net of tax, Reclassified from Amount of Gain or (Loss), net of Derivatives in tax, Recognized in OCI on Accumulated OCI into Earnings on tax, Recognized in Earnings on Cash Flow Statement of Derivatives (Effective Portion) Derivatives (Effective Portion) Derivatives (Ineffective Portion) Hedging Earnings Three Months (13 Weeks) Ended Three Months (13 Weeks) Ended Three Months (13 Weeks) Ended Relationships Location July 1, 2017 July 2, 2016 July 1, 2017 July 2, 2016 July 1, 2017 July 2, 2016 Commodity contracts Cost of $ (71 ) $ 3,243 $ (171 ) $ (3,257 ) $ — $ — Derivatives in Cash Flow Statement of Amount of Gain or (Loss), net of tax, Recognized in OCI on Derivatives (Effective Portion) Amount of Gain or (Loss), net of tax, Reclassified from Accumulated OCI into Earnings on Amount of Gain or (Loss), net of tax, Recognized in Earnings on Derivatives (Ineffective Portion) Hedging Earnings Six Months (26 Weeks) Ended Six Months (26 Weeks) Ended Six Months (26 Weeks) Ended Relationships Location July 1, 2017 July 2, 2016 July 1, 2017 July 2, 2016 July 1, 2017 July 2, 2016 Commodity contracts Cost of $ (1,706 ) $ 1,512 $ (656 ) $ (6,288 ) $ — $ — Derivatives Not Designated as Hedging Instruments Amount of Gain or (Loss) Recognized in Earnings on Derivatives Derivatives Not Designated as Statement of Three Months (13 Weeks) Ended Six Months (26 Weeks) Ended Hedging Instruments Earnings Location July 1, 2017 July 2, 2016 July 1, 2017 July 2, 2016 Commodity contracts Cost of products sold $ (364 ) $ (962 ) $ (2,919 ) $ (874 ) Foreign exchange contracts Cost of products sold (1,449 ) (13 ) (2,345 ) (831 ) Total $ (1,813 ) $ (975 ) $ (5,264 ) $ (1,705 )

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jul. 01, 2017
Fair Value Disclosures [Abstract]
Fair Value Measurements	10. FAIR VALUE MEASUREMENTS: The following table summarizes information regarding Nucor’s financial assets and financial liabilities that are measured at fair value as of July 1, 2017 and December 31, 2016 (in thousands). Nucor does not have any non-financial non-financial Fair Value Measurements at Reporting Date Using Description Carrying Amount in Condensed Consolidated Balance Sheets Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) As of July 1, 2017 Assets: Cash equivalents $ 1,092,015 $ 1,092,015 $ — $ — Short-term investments 50,000 50,000 — — Commodity contracts 200 — 200 — Total assets $ 1,142,215 $ 1,142,015 $ 200 $ — Liabilities: Commodity and foreign exchange contracts $ (2,590 ) $ — $ (2,590 ) $ — As of December 31, 2016 Assets: Cash equivalents $ 1,609,523 $ 1,609,523 $ — $ — Short-term investments 150,000 150,000 — — Commodity and foreign exchange contracts 2,029 — 2,029 — Total assets $ 1,761,552 $ 1,759,523 $ 2,029 $ — Liabilities: Commodity contracts $ (605 ) $ — $ (605 ) $ — Fair value measurements for Nucor’s cash equivalents and short-term investments are classified under Level 1 because such measurements are based on quoted market prices in active markets for identical assets. Our short-term investments are held in similar short-term investment instruments as described in Note 4 to the audited consolidated financial statements included in Nucor’s Annual Report on Form 10-K The fair value of short-term and long-term debt, including current maturities, was approximately $4.75 billion at July 1, 2017 ($4.70 billion at December 31, 2016). The debt fair value estimates are classified under Level 2 because such estimates are based on readily available market prices of our debt at July 1, 2017 and December 31, 2016, or similar debt with the same maturities, ratings and interest rates.

Contingencies

Contingencies	6 Months Ended
	Jul. 01, 2017
Commitments and Contingencies Disclosure [Abstract]
Contingencies	11. CONTINGENCIES: Nucor is subject to environmental laws and regulations established by federal, state and local authorities and, accordingly, makes provision for the estimated costs of compliance. Of the undiscounted total of $17.4 million of accrued environmental costs at July 1, 2017 ($21.9 million at December 31, 2016), $5.1 million was classified in accrued expenses and other current liabilities ($9.5 million at December 31, 2016) and $12.3 million was classified in deferred credits and other liabilities ($12.4 million at December 31, 2016). Inherent uncertainties exist in these estimates primarily due to unknown conditions, evolving remediation technology and changing governmental regulations and legal standards. We are from time to time a party to various lawsuits, claims and other legal proceedings that arise in the ordinary course of business. With respect to all such lawsuits, claims and proceedings, we record reserves when it is probable a liability has been incurred and the amount of loss can be reasonably estimated. We do not believe that any of these proceedings, individually or in the aggregate, would be expected to have a material adverse effect on our results of operations, financial position or cash flows. Nucor maintains liability insurance for certain risks that is subject to certain self-insurance limits.

Stock-Based Compensation

Stock-Based Compensation	6 Months Ended
	Jul. 01, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation	12. STOCK-BASED COMPENSATION: Stock Options – Stock options may be granted to Nucor’s key employees, officers and non-employee A summary of activity under Nucor’s stock option plans for the first six months of 2017 is as follows (in thousands, except years and per share amounts): Weighted - Weighted - Average Average Aggregate Exercise Remaining Intrinsic Shares Price Contractual Life Value Number of shares under stock options: Outstanding at beginning of year 3,591 $ 45.32 Granted 698 $ 59.07 Exercised (92 ) $ 38.56 $ 2,278 Canceled — — Outstanding at July 1, 2017 4,197 $ 47.75 7.3 years $ 43,313 Stock options exercisable at July 1, 2017 1,900 $ 43.16 5.4 years $ 27,960 For the 2017 stock option grant, the grant date fair value of $12.61 per share was calculated using the Black-Scholes option-pricing model with the following assumptions: Exercise price $ 59.07 Expected dividend yield 2.56 % Expected stock price volatility 26.53 % Risk-free interest rate 2.02 % Expected life (years) 6.5 Stock options granted to employees who are eligible for retirement on the date of grant are expensed immediately since these awards vest upon retirement from the Company. Retirement, for purposes of vesting in these stock options, means termination of employment after satisfying age and years of service requirements. Similarly, stock options granted to employees who will become retirement-eligible prior to the end of the vesting term are expensed over the period through which the employee will become retirement-eligible. Compensation expense for stock options granted to employees who will not become retirement-eligible prior to the end of the vesting term is recognized on a straight-line basis over the vesting period. Compensation expense for stock options was $7.2 million and $7.1 million in the second quarter of 2017 and 2016, respectively, and $7.5 million and $7.3 million in the first six months of 2017 and 2016, respectively. As of July 1, 2017, unrecognized compensation expense related to stock options was $2.9 million, which is expected to be recognized over a weighted-average period of 2.4 years. Restricted Stock Units – Nucor annually grants restricted stock units (RSUs) to key employees, officers and non-employee non-employee non-employee RSUs granted to employees who are eligible for retirement on the date of grant are expensed immediately, and RSUs granted to employees who will become retirement-eligible prior to the end of the vesting term are expensed over the period through which the employee will become retirement-eligible since these awards vest upon retirement from the Company. Compensation expense for RSUs granted to employees who will not become retirement-eligible prior to the end of the vesting term is recognized on a straight-line basis over the vesting period. Cash dividend equivalents are paid to holders of RSUs each quarter. Dividend equivalents paid on RSUs expected to vest are recognized as a reduction in retained earnings. The fair value of an RSU is determined based on the closing stock price of Nucor’s common stock on the date of the grant A summary of Nucor’s RSU activity for the first six months of 2017 is as follows (shares in thousands): Grant Date Shares Fair Value Restricted stock units: Unvested at beginning of year 1,040 $ 48.47 Granted 721 $ 59.07 Vested (630 ) $ 53.21 Canceled (10 ) $ 49.38 Unvested at July 1, 2017 1,121 $ 52.62 Shares reserved for future grants (stock options and RSUs) 7,278 Compensation expense for RSUs was $21.1 million and $18.3 million in the second quarter of 2017 and 2016, respectively, and $26.1 million and $23.2 million in the first six months of 2017 and 2016, respectively. As of July 1, 2017, unrecognized compensation expense related to unvested RSUs was $46.3 million, which is expected to be recognized over a weighted-average period of 2.5 years. Restricted Stock Awards – Nucor’s Senior Officers Long-Term Incentive Plan (LTIP) and Senior Officers Annual Incentive Plan (AIP) authorize the award of shares of common stock to officers subject to certain conditions and restrictions. The LTIP provides for the award of shares of restricted common stock at the end of each LTIP performance measurement period at no cost to officers if certain financial performance goals are met during the period. One-third The AIP provides for the payment of annual cash incentive awards. An AIP participant may elect, however, to defer payment of up to one-half A summary of Nucor’s restricted stock activity under the AIP and the LTIP for the first six months of 2017 is as follows (shares in thousands): Grant Date Shares Fair Value Restricted stock awards and units: Unvested at beginning of year 67 $ 45.77 Granted 172 $ 60.62 Vested (144 ) $ 51.69 Canceled — — Unvested at July 1, 2017 95 $ 54.45 Shares reserved for future grants 683 Compensation expense for common stock and common stock units awarded under the AIP and the LTIP is recorded over the performance measurement and vesting periods based on the anticipated number and market value of shares of common stock and common stock units to be awarded. Compensation expense for anticipated awards based upon Nucor’s financial performance, exclusive of amounts payable in cash, was $3.2 million and $4.8 million in the second quarter of 2017 and 2016, respectively, and $7.5 million and $7.0 million in the first six months of 2017 and 2016, respectively. As of July 1, 2017, unrecognized compensation expense related to unvested restricted stock awards was $1.6 million, which is expected to be recognized over a weighted-average period of 2.1 years.

Employee Benefit Plan

Employee Benefit Plan	6 Months Ended
	Jul. 01, 2017
Compensation and Retirement Disclosure [Abstract]
Employee Benefit Plan	13. EMPLOYEE BENEFIT PLAN: Nucor makes contributions to a Profit Sharing and Retirement Savings Plan for qualified employees based on the profitability of the Company. Nucor’s expense for these benefits totaled $48.5 million and $36.0 million in the second quarter of 2017 and 2016, respectively, and $102.5 million and $47.8 million in the first six months of 2017 and 2016, respectively. The related liability for these benefits is included in salaries, wages and related accruals in the condensed consolidated balance sheets.

Interest Expense (Income)

Interest Expense (Income)	6 Months Ended
	Jul. 01, 2017
Banking and Thrift, Interest [Abstract]
Interest Expense (Income)	14. INTEREST EXPENSE (INCOME): The components of net interest expense are as follows (in thousands): Three Months (13 Weeks) Ended Six Months (26 Weeks) Ended July 1, 2017 July 2, 2016 July 1, 2017 July 2, 2016 Interest expense $ 47,565 $ 43,477 $ 93,865 $ 90,851 Interest income (2,985 ) (2,993 ) (5,680 ) (5,445 ) Interest expense, net $ 44,580 $ 40,484 $ 88,185 $ 85,406

Income Taxes

Income Taxes	6 Months Ended
	Jul. 01, 2017
Income Tax Disclosure [Abstract]
Income Taxes	15. INCOME TAXES: The effective tax rate for the second quarter of 2017 was 32.7% compared to 30.4% for the second quarter of 2016. The increase in the effective tax rate for the second quarter of 2017 as compared to the second quarter of 2016 was primarily due to the change in relative proportions of net earnings attributable to noncontrolling interests to total pre-tax Nucor has concluded U.S. federal income tax matters for years through 2012. The tax years 2013 through 2015 remain open to examination by the Internal Revenue Service. The Canada Revenue Agency has substantially concluded its examination of the 2012 Canadian returns for Harris Steel Group Inc. and certain related affiliates and is now examining the 2013 Canadian returns. The tax years 2009 through 2016 remain open to examination by other major taxing jurisdictions to which Nucor is subject (primarily Canada and other state and local jurisdictions). Non-current Non-current

Stockholders' Equity

Stockholders' Equity	6 Months Ended
	Jul. 01, 2017
Equity [Abstract]
Stockholders' Equity	16. STOCKHOLDERS’ EQUITY: The following tables reflect the changes in stockholders’ equity attributable to both Nucor and the noncontrolling interests of Nucor’s joint ventures, primarily Nucor-Yamato Steel Company, of which Nucor owns 51% (in thousands): Attributable to Attributable to Nucor Corporation Noncontrolling Interests Total Stockholders’ equity at December 31, 2016 $ 7,879,865 $ 374,843 $ 8,254,708 Total comprehensive income 704,855 39,425 744,280 Stock options 11,068 — 11,068 Issuance of stock under award plans, net of forfeitures 23,593 — 23,593 Amortization of unearned compensation 700 — 700 Dividends declared (243,016 ) — (243,016 ) Distributions to noncontrolling interests — (79,420 ) (79,420 ) Stockholders’ equity at July 1, 2017 $ 8,377,065 $ 334,848 $ 8,711,913 Attributable to Attributable to Nucor Corporation Noncontrolling Interests Total Stockholders’ equity at December 31, 2015 $ 7,477,816 $ 372,061 $ 7,849,877 Total comprehensive income 401,169 62,681 463,850 Stock options 9,215 — 9,215 Issuance of stock under award plans, net of forfeitures 18,973 — 18,973 Amortization of unearned compensation 500 — 500 Treasury stock acquired (5,173 ) — (5,173 ) Dividends declared (240,538 ) — (240,538 ) Distributions to noncontrolling interests — (78,684 ) (78,684 ) Other (602 ) (1,776 ) (2,378 ) Stockholders’ equity at July 2, 2016 $ 7,661,360 $ 354,282 $ 8,015,642 In September 2015, the Company announced that the Board of Directors had approved a stock repurchase program under which the Company is authorized to repurchase up to $900 million of the Company’s common stock. This $900 million share repurchase program has no stated expiration and replaced any previously authorized repurchase programs. As of July 1, 2017, the Company had $828.3 million remaining available under the program. The Company expects any share repurchases to be made through purchases from time to time in the open market at prevailing market prices, through private transactions or block trades. The timing and amount of any repurchases will depend on market conditions, share price, applicable legal requirements and other factors.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Loss)	6 Months Ended
	Jul. 01, 2017
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated Other Comprehensive Income (Loss)	17. ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS): The following tables reflect the changes in accumulated other comprehensive income (loss) by component (in thousands): Three-Month (13 Week) Period Ended July 1, 2017 Gains and Losses on Foreign Currency Adjustment to Early Hedging Derivatives Gain (Loss) Retiree Medical Plan Total Accumulated other comprehensive loss at April 1, 2017 $ (400 ) $ (324,169 ) $ 7,577 $ (316,992 ) Other comprehensive income (loss) before reclassifications (71 ) 23,957 — 23,886 Amounts reclassified from accumulated other comprehensive income (loss) into earnings (1) 171 — — 171 Net current-period other comprehensive income (loss) 100 23,957 — 24,057 Accumulated other comprehensive loss at July 1, 2017 $ (300 ) $ (300,212 ) $ 7,577 $ (292,935 ) Six-Month July 1, 2017 Gains and Losses on Foreign Currency Adjustment to Early Hedging Derivatives Gain (Loss) Retiree Medical Plan Total Accumulated other comprehensive loss at December 31, 2016 $ 750 $ (326,170 ) $ 7,577 $ (317,843 ) Other comprehensive income (loss) before reclassifications (1,706 ) 25,958 — 24,252 Amounts reclassified from accumulated other comprehensive income (loss) into earnings (1) 656 — — 656 Net current-period other comprehensive income (loss) (1,050 ) 25,958 — 24,908 Accumulated other comprehensive loss at July 1, 2017 $ (300 ) $ (300,212 ) $ 7,577 $ (292,935 ) (1) Includes $171 and $656 of accumulated other comprehensive income reclassifications into cost of products sold for net losses on commodity contracts in the second quarter and first six months of 2017, respectively. The tax impacts of those reclassifications were $0 and $300, respectively. Three-Month (13 Week) Period Ended July 2, 2016 Gains and Losses on Foreign Currency Adjustment to Early Hedging Derivatives Gain (Loss) Retiree Medical Plan Total Accumulated other comprehensive loss at April 2, 2016 $ (10,400 ) $ (297,768 ) $ 12,003 $ (296,165 ) Other comprehensive income (loss) before reclassifications 3,243 8,287 — 11,530 Amounts reclassified from accumulated other comprehensive income (loss) into earnings (2) 3,257 — — 3,257 Net current-period other comprehensive income (loss) 6,500 8,287 — 14,787 Accumulated other comprehensive loss at July 2, 2016 $ (3,900 ) $ (289,481 ) $ 12,003 $ (281,378 ) Six-Month July 2, 2016 Gains and Losses on Foreign Currency Adjustment to Early Hedging Derivatives Gain (Loss) Retiree Medical Plan Total Accumulated other comprehensive loss at December 31, 2015 $ (11,700 ) $ (351,665 ) $ 12,003 $ (351,362 ) Other comprehensive income (loss) before reclassifications 1,512 62,184 — 63,696 Amounts reclassified from accumulated other comprehensive income (loss) into earnings (2) 6,288 — — 6,288 Net current-period other comprehensive income (loss) 7,800 62,184 — 69,984 Accumulated other comprehensive loss at July 2, 2016 $ (3,900 ) $ (289,481 ) $ 12,003 $ (281,378 ) (2) Includes $3,257 and $6,288 of accumulated other comprehensive income reclassifications into cost of products sold for net losses on commodity contracts in the second quarter and first six months of 2016, respectively. The tax impacts of those reclassifications were $1,900 and $3,600, respectively.

Segments

Segments	6 Months Ended
	Jul. 01, 2017
Segment Reporting [Abstract]
Segments	18. 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 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. The balance of earnings (loss) before income taxes and noncontrolling interests as of and for the periods ended July 2, 2016 was adjusted due to the change in accounting principle from LIFO to FIFO for certain inventories (see Note 1). Nucor’s results by segment were as follows (in thousands): Three Months (13 Weeks) Ended Six Months (26 Weeks) Ended July 1, 2017 July 2, 2016 July 1, 2017 July 2, 2016 Net sales to external customers: Steel mills $ 3,800,359 $ 3,016,322 $ 7,343,148 $ 5,650,911 Steel products 970,398 923,357 1,830,473 1,751,733 Raw materials 404,012 306,093 816,327 558,704 $ 5,174,769 $ 4,245,772 $ 9,989,948 $ 7,961,348 Intercompany sales: Steel mills $ 760,937 $ 554,395 $ 1,421,855 $ 1,024,658 Steel products 24,972 27,954 52,115 49,160 Raw materials 2,459,352 1,771,470 4,637,991 2,942,832 Corporate/eliminations (3,245,261 ) (2,353,819 ) (6,111,961 ) (4,016,650 ) $ — $ — $ — $ — Earnings (loss) before income taxes and noncontrolling interests: Steel mills $ 617,366 $ 530,727 $ 1,301,527 $ 811,099 Steel products 45,809 82,946 72,731 125,313 Raw materials 66,227 (27,181 ) 92,618 (90,553 ) Corporate/eliminations (221,266 ) (196,608 ) (409,765 ) (286,412 ) $ 508,136 $ 389,884 $ 1,057,111 $ 559,447 July 1, 2017 Dec. 31, 2016 Segment assets: Steel mills $ 9,230,612 $ 8,084,773 Steel products 2,691,020 2,544,344 Raw materials 3,316,269 3,235,237 Corporate/eliminations 874,824 1,359,164 $ 16,112,725 $ 15,223,518

Earnings Per Share

Earnings Per Share	6 Months Ended
	Jul. 01, 2017
Earnings Per Share [Abstract]
Earnings Per Share	19. EARNINGS PER SHARE: The computations of basic and diluted net earnings per share are as follows (in thousands, except per share amounts): Three Months (13 Weeks) Ended Six Months (26 Weeks) Ended July 1, 2017 July 2, 2016 July 1, 2017 July 2, 2016 Basic net earnings per share: Basic net earnings $ 323,048 $ 243,620 $ 679,947 $ 331,185 Earnings allocated to participating securities (1,138 ) (852 ) (2,333 ) (1,089 ) Net earnings available to common stockholders $ 321,910 $ 242,768 $ 677,614 $ 330,096 Average shares outstanding 320,439 319,360 320,332 319,299 Basic net earnings per share $ 1.00 $ 0.76 $ 2.12 $ 1.03 Diluted net earnings per share: Diluted net earnings $ 323,048 $ 243,620 $ 679,947 $ 331,185 Earnings allocated to participating securities (1,136 ) (852 ) (2,328 ) (1,089 ) Net earnings available to common stockholders $ 321,912 $ 242,768 $ 677,619 $ 330,096 Diluted average shares outstanding: Basic shares outstanding 320,439 319,360 320,332 319,299 Dilutive effect of stock options and other 787 223 854 138 321,226 319,583 321,186 319,437 Diluted net earnings per share $ 1.00 $ 0.76 $ 2.11 $ 1.03 The following stock options were excluded from the computation of diluted net earnings per share because their effect would have been anti-dilutive (in thousands, except per share amounts): Three Months (13 Weeks) Ended Six Months (26 Weeks) Ended July 1, 2017 July 2, 2016 July 1, 2017 July 2, 2016 Anti-dilutive stock options: Weighted-average shares 698 1,334 349 1,874 Weighted-average exercise price $ 59.07 $ 49.40 $ 59.07 $ 47.04

Basis of Interim Presentation (

Basis of Interim Presentation (Policies)	6 Months Ended
	Jul. 01, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Recently Adopted Accounting Pronouncements	Recently Adopted Accounting Pronouncements – In the first quarter of 2017, Nucor adopted new accounting guidance that amends the accounting for employee share-based payment transactions. This new standard requires income statement recognition of all tax effects, including all excess tax benefits and tax deficiencies, resulting from the settlement of share-based awards in the reporting period in which they occur. The standard also requires that all tax-related In January 2017, new guidance was issued regarding the simplification of the test for goodwill impairment. The new guidance eliminates Step 2 from the goodwill impairment test and will require an entity to perform its annual, or interim, goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount. The new guidance is effective for the Company for annual and interim reporting periods beginning after December 15, 2019, with early adoption permitted. The Company early adopted this new guidance in the first quarter of 2017. The adoption of this new guidance did not have a material impact on the Company’s consolidated financial statements.
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements - In May 2014, new accounting guidance was issued that will supersede nearly all existing accounting guidance related to revenue recognition. The new guidance provides that an entity recognizes revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. This update also requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts, including significant judgments and changes in judgments, and assets recognized from costs incurred to obtain or fulfill a contract. The Financial Accounting Standards Board has also issued a number of updates to this new accounting guidance. The standard is effective for the Company for annual and interim reporting periods beginning after December 15, 2017 and is not expected to have a material effect on the Company’s consolidated financial statements. In January 2016, new accounting guidance was issued regarding the recognition and measurement of financial assets and financial liabilities. Changes to the current accounting guidance primarily affect the accounting for equity investments, financial liabilities under the fair value option, and the presentation and disclosure requirements for financial instruments. In addition, the Financial Accounting Standards Board clarified guidance related to the valuation allowance assessment when recognizing deferred tax assets resulting from unrealized losses on available-for-sale In February 2016, new accounting guidance was issued regarding the accounting for leases. The new guidance requires all lessees to recognize on the balance sheet right to use assets and lease liabilities for the rights and obligations created by lease arrangements with terms greater than 12 months. The standard is effective for the Company for annual and interim reporting periods beginning after December 15, 2018. The Company is evaluating the impact that the adoption of this new guidance will have on its consolidated financial statements, but we expect that assets and liabilities will increase on the consolidated balance sheet. In August 2016, new accounting guidance was issued regarding the presentation and classification of certain cash receipts and cash payments in the statement of cash flows. The new guidance addresses specific cash flow presentation issues in order to reduce diversity in existing practice. The new guidance is effective for the Company for annual and interim reporting periods beginning after December 15, 2017. The Company is evaluating the impact that the adoption of this new guidance will have on its consolidated financial statements. In October 2016, new accounting guidance was issued regarding intra-entity transfers of assets other than inventory. The new guidance requires that an entity should recognize the income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs. The new guidance is effective for the Company for annual and interim reporting periods beginning after December 15, 2017. The Company is evaluating the impact that the adoption of this new guidance will have on its consolidated financial statements.
Prior Year Change in Accounting Principle	Prior Year Change in Accounting Principle - In the fourth quarter of 2016, the Company changed its accounting method for valuing its inventories held by the parent company and Nucor-Yamato Steel Company to the first-in, first-out last-in, first-out

Basis of Interim Presentation27

Basis of Interim Presentation (Tables)	6 Months Ended
	Jul. 01, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Adjustments to Condensed Consolidated Financial Statements and Effect of Change in Accounting Principle from LIFO to FIFO on Net Earnings	As a result of the retrospective application of the change in accounting principle, certain financial statement line items in the Company’s condensed consolidated statements of earnings for the three- and six-month six-month (in thousands, except per share data) As Originally Reported Effect of Change As Currently Reported Condensed Consolidated Statement of Earnings for the Three Months (13 Weeks) Ended July 2, 2016: Cost of products sold $ 3,679,512 $ (19,000 ) $ 3,660,512 Provision for income taxes 112,548 5,967 118,515 Net earnings 258,336 13,033 271,369 Earnings attributable to noncontrolling interests 24,564 3,185 27,749 Net earnings attributable to Nucor stockholders 233,772 9,848 243,620 Net earnings per share: Basic $ 0.73 $ 0.03 $ 0.76 Diluted $ 0.73 $ 0.03 $ 0.76 (in thousands, except per share data) As Originally Reported Effect of Change As Currently Reported Condensed Consolidated Statement of Earnings for the Six Months (26 Weeks) Ended July 2, 2016: Cost of products sold $ 7,108,140 $ (47,037 ) $ 7,061,103 Provision for income taxes 149,613 15,968 165,581 Net earnings 362,797 31,069 393,866 Earnings attributable to noncontrolling interests 58,271 4,410 62,681 Net earnings attributable to Nucor stockholders 304,526 26,659 331,185 Net earnings per share: Basic $ 0.95 $ 0.08 $ 1.03 Diluted $ 0.95 $ 0.08 $ 1.03 (in thousands) Condensed Consolidated Statement of Cash Flows for the Six Months (26 Weeks) Ended July 2, 2016: Net earnings $ 362,797 $ 31,069 $ 393,866 Changes in inventories (136,019 ) (47,037 ) (183,056 ) Changes in deferred income taxes (4,281 ) 15,968 11,687

Acquisitions and Dispositions (

Acquisitions and Dispositions (Tables) - Republic [Member]	6 Months Ended
	Jul. 01, 2017
Fair Values of Assets Acquired and Liabilities Assumed	The following table summarizes the fair values of the assets acquired and liabilities assumed of Republic as of the date of acquisition (in thousands): Cash $ 206 Accounts receivable 39,177 Inventory 33,561 Other current assets 1,101 Property, plant and equipment 67,412 Goodwill 115,562 Other intangible assets 89,200 Other assets 3,118 Total assets acquired 349,337 Current liabilities 17,743 Total liabilities assumed 17,743 Net assets acquired $ 331,594
Purchase Price Allocation of Identifiable Intangible Assets	The following table summarizes the purchase price allocation to the identifiable intangible assets of Republic as of the date of acquisition (in thousands, except years): Weighted - Customer relationships $ 80,800 12 years Trademarks and trade names 8,400 13 years $ 89,200

Goodwill and Other Intangible29

Goodwill and Other Intangible Assets (Tables)	6 Months Ended
	Jul. 01, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Change in Net Carrying Amount of Goodwill by Segment	6. GOODWILL AND OTHER INTANGIBLE ASSETS: The change in the net carrying amount of goodwill for the six months ended July 1, 2017, by segment is as follows (in thousands): Steel Mills Steel Products Raw Materials Total Balance at December 31, 2016 $ 620,156 $ 702,995 $ 729,577 $ 2,052,728 Acquisitions 125,328 — — 125,328 Translation — 1,585 — 1,585 Balance at July 1, 2017 $ 745,484 $ 704,580 $ 729,577 $ 2,179,641
Schedule of Intangible Assets	Intangible assets with estimated useful lives of 5 to 22 years are amortized on a straight-line or accelerated basis and are comprised of the following (in thousands): July 1, 2017 December 31, 2016 Gross Accumulated Gross Accumulated Customer relationships $ 1,409,125 $ 603,734 $ 1,295,803 $ 566,884 Trademarks and trade names 174,116 71,843 161,851 66,494 Other 62,807 23,493 62,807 20,248 $ 1,646,048 $ 699,070 $ 1,520,461 $ 653,626

Derivatives (Tables)

Derivatives (Tables)	6 Months Ended
	Jul. 01, 2017
Fair Value of Derivative Instruments	The following tables summarize information regarding Nucor’s derivative instruments (in thousands): Fair Value of Derivative Instruments Fair Value at Balance Sheet Location July 1, 2017 Dec. 31, 2016 Asset derivatives designated as hedging instruments: Commodity contracts Other current assets $ 200 $ 1,250 Asset derivatives not designated as hedging instruments: Foreign exchange contracts Other current assets — 779 Total asset derivatives $ 200 $ 2,029 Liability derivatives designated as hedging instruments: Commodity contracts Deferred credits and other liabilities $ (700 ) $ — Liability derivatives not designated as hedging instruments: Commodity contracts Accrued expenses and other current liabilities (658 ) (605 ) Foreign exchange contracts Accrued expenses and other current liabilities (1,232 ) — Total liability derivatives not designated as hedging instruments (1,890 ) (605 ) Total liability derivatives $ (2,590 ) $ (605 )
Derivatives Not Designated as Hedging Instrument [Member]
Effect of Derivative Instruments on Condensed Consolidated Statements of Earnings	Derivatives Not Designated as Hedging Instruments Amount of Gain or (Loss) Recognized in Earnings on Derivatives Derivatives Not Designated as Statement of Three Months (13 Weeks) Ended Six Months (26 Weeks) Ended Hedging Instruments Earnings Location July 1, 2017 July 2, 2016 July 1, 2017 July 2, 2016 Commodity contracts Cost of products sold $ (364 ) $ (962 ) $ (2,919 ) $ (874 ) Foreign exchange contracts Cost of products sold (1,449 ) (13 ) (2,345 ) (831 ) Total $ (1,813 ) $ (975 ) $ (5,264 ) $ (1,705 )
Derivatives Designated as Hedging Instrument [Member]
Effect of Derivative Instruments on Condensed Consolidated Statements of Earnings	The Effect of Derivative Instruments on the Condensed Consolidated Statements of Earnings Derivatives Designated as Hedging Instruments Amount of Gain or (Loss), net of Amount of Gain or (Loss), net of tax, Reclassified from Amount of Gain or (Loss), net of Derivatives in tax, Recognized in OCI on Accumulated OCI into Earnings on tax, Recognized in Earnings on Cash Flow Statement of Derivatives (Effective Portion) Derivatives (Effective Portion) Derivatives (Ineffective Portion) Hedging Earnings Three Months (13 Weeks) Ended Three Months (13 Weeks) Ended Three Months (13 Weeks) Ended Relationships Location July 1, 2017 July 2, 2016 July 1, 2017 July 2, 2016 July 1, 2017 July 2, 2016 Commodity contracts Cost of $ (71 ) $ 3,243 $ (171 ) $ (3,257 ) $ — $ — Derivatives in Cash Flow Statement of Amount of Gain or (Loss), net of tax, Recognized in OCI on Derivatives (Effective Portion) Amount of Gain or (Loss), net of tax, Reclassified from Accumulated OCI into Earnings on Amount of Gain or (Loss), net of tax, Recognized in Earnings on Derivatives (Ineffective Portion) Hedging Earnings Six Months (26 Weeks) Ended Six Months (26 Weeks) Ended Six Months (26 Weeks) Ended Relationships Location July 1, 2017 July 2, 2016 July 1, 2017 July 2, 2016 July 1, 2017 July 2, 2016 Commodity contracts Cost of $ (1,706 ) $ 1,512 $ (656 ) $ (6,288 ) $ — $ —

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jul. 01, 2017
Fair Value Disclosures [Abstract]
Schedule of Financial Assets and Liabilities Measured at Fair Value	The following table summarizes information regarding Nucor’s financial assets and financial liabilities that are measured at fair value as of July 1, 2017 and December 31, 2016 (in thousands). Nucor does not have any non-financial non-financial Fair Value Measurements at Reporting Date Using Description Carrying Amount in Condensed Consolidated Balance Sheets Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) As of July 1, 2017 Assets: Cash equivalents $ 1,092,015 $ 1,092,015 $ — $ — Short-term investments 50,000 50,000 — — Commodity contracts 200 — 200 — Total assets $ 1,142,215 $ 1,142,015 $ 200 $ — Liabilities: Commodity and foreign exchange contracts $ (2,590 ) $ — $ (2,590 ) $ — As of December 31, 2016 Assets: Cash equivalents $ 1,609,523 $ 1,609,523 $ — $ — Short-term investments 150,000 150,000 — — Commodity and foreign exchange contracts 2,029 — 2,029 — Total assets $ 1,761,552 $ 1,759,523 $ 2,029 $ — Liabilities: Commodity contracts $ (605 ) $ — $ (605 ) $ —

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	6 Months Ended
	Jul. 01, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary of Stock Option Plans Activity	A summary of activity under Nucor’s stock option plans for the first six months of 2017 is as follows (in thousands, except years and per share amounts): Weighted - Weighted - Average Average Aggregate Exercise Remaining Intrinsic Shares Price Contractual Life Value Number of shares under stock options: Outstanding at beginning of year 3,591 $ 45.32 Granted 698 $ 59.07 Exercised (92 ) $ 38.56 $ 2,278 Canceled — — Outstanding at July 1, 2017 4,197 $ 47.75 7.3 years $ 43,313 Stock options exercisable at July 1, 2017 1,900 $ 43.16 5.4 years $ 27,960
Schedule of Grant Date Fair Value Black-Scholes Option-Pricing Model Assumptions	For the 2017 stock option grant, the grant date fair value of $12.61 per share was calculated using the Black-Scholes option-pricing model with the following assumptions: Exercise price $ 59.07 Expected dividend yield 2.56 % Expected stock price volatility 26.53 % Risk-free interest rate 2.02 % Expected life (years) 6.5
Summary of Nucor's RSU Activity	A summary of Nucor’s RSU activity for the first six months of 2017 is as follows (shares in thousands): Grant Date Shares Fair Value Restricted stock units: Unvested at beginning of year 1,040 $ 48.47 Granted 721 $ 59.07 Vested (630 ) $ 53.21 Canceled (10 ) $ 49.38 Unvested at July 1, 2017 1,121 $ 52.62 Shares reserved for future grants (stock options and RSUs) 7,278
Summary of Nucor's Restricted Stock Activity under AIP and LTIP	A summary of Nucor’s restricted stock activity under the AIP and the LTIP for the first six months of 2017 is as follows (shares in thousands): Grant Date Shares Fair Value Restricted stock awards and units: Unvested at beginning of year 67 $ 45.77 Granted 172 $ 60.62 Vested (144 ) $ 51.69 Canceled — — Unvested at July 1, 2017 95 $ 54.45 Shares reserved for future grants 683

Interest Expense (Income) (Tabl

Interest Expense (Income) (Tables)	6 Months Ended
	Jul. 01, 2017
Banking and Thrift, Interest [Abstract]
Schedule of Components of Net Interest Expense	The components of net interest expense are as follows (in thousands): Three Months (13 Weeks) Ended Six Months (26 Weeks) Ended July 1, 2017 July 2, 2016 July 1, 2017 July 2, 2016 Interest expense $ 47,565 $ 43,477 $ 93,865 $ 90,851 Interest income (2,985 ) (2,993 ) (5,680 ) (5,445 ) Interest expense, net $ 44,580 $ 40,484 $ 88,185 $ 85,406

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	6 Months Ended
	Jul. 01, 2017
Equity [Abstract]
Schedule of Changes in Stockholders' Equity	The following tables reflect the changes in stockholders’ equity attributable to both Nucor and the noncontrolling interests of Nucor’s joint ventures, primarily Nucor-Yamato Steel Company, of which Nucor owns 51% (in thousands): Attributable to Attributable to Nucor Corporation Noncontrolling Interests Total Stockholders’ equity at December 31, 2016 $ 7,879,865 $ 374,843 $ 8,254,708 Total comprehensive income 704,855 39,425 744,280 Stock options 11,068 — 11,068 Issuance of stock under award plans, net of forfeitures 23,593 — 23,593 Amortization of unearned compensation 700 — 700 Dividends declared (243,016 ) — (243,016 ) Distributions to noncontrolling interests — (79,420 ) (79,420 ) Stockholders’ equity at July 1, 2017 $ 8,377,065 $ 334,848 $ 8,711,913 Attributable to Attributable to Nucor Corporation Noncontrolling Interests Total Stockholders’ equity at December 31, 2015 $ 7,477,816 $ 372,061 $ 7,849,877 Total comprehensive income 401,169 62,681 463,850 Stock options 9,215 — 9,215 Issuance of stock under award plans, net of forfeitures 18,973 — 18,973 Amortization of unearned compensation 500 — 500 Treasury stock acquired (5,173 ) — (5,173 ) Dividends declared (240,538 ) — (240,538 ) Distributions to noncontrolling interests — (78,684 ) (78,684 ) Other (602 ) (1,776 ) (2,378 ) Stockholders’ equity at July 2, 2016 $ 7,661,360 $ 354,282 $ 8,015,642

Accumulated Other Comprehensi35

Accumulated Other Comprehensive Income (Loss) (Tables)	6 Months Ended
	Jul. 01, 2017
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Components of Accumulated Other Comprehensive Income (Loss)	The following tables reflect the changes in accumulated other comprehensive income (loss) by component (in thousands): Three-Month (13 Week) Period Ended July 1, 2017 Gains and Losses on Foreign Currency Adjustment to Early Hedging Derivatives Gain (Loss) Retiree Medical Plan Total Accumulated other comprehensive loss at April 1, 2017 $ (400 ) $ (324,169 ) $ 7,577 $ (316,992 ) Other comprehensive income (loss) before reclassifications (71 ) 23,957 — 23,886 Amounts reclassified from accumulated other comprehensive income (loss) into earnings (1) 171 — — 171 Net current-period other comprehensive income (loss) 100 23,957 — 24,057 Accumulated other comprehensive loss at July 1, 2017 $ (300 ) $ (300,212 ) $ 7,577 $ (292,935 ) Six-Month July 1, 2017 Gains and Losses on Foreign Currency Adjustment to Early Hedging Derivatives Gain (Loss) Retiree Medical Plan Total Accumulated other comprehensive loss at December 31, 2016 $ 750 $ (326,170 ) $ 7,577 $ (317,843 ) Other comprehensive income (loss) before reclassifications (1,706 ) 25,958 — 24,252 Amounts reclassified from accumulated other comprehensive income (loss) into earnings (1) 656 — — 656 Net current-period other comprehensive income (loss) (1,050 ) 25,958 — 24,908 Accumulated other comprehensive loss at July 1, 2017 $ (300 ) $ (300,212 ) $ 7,577 $ (292,935 ) (1) Includes $171 and $656 of accumulated other comprehensive income reclassifications into cost of products sold for net losses on commodity contracts in the second quarter and first six months of 2017, respectively. The tax impacts of those reclassifications were $0 and $300, respectively. Three-Month (13 Week) Period Ended July 2, 2016 Gains and Losses on Foreign Currency Adjustment to Early Hedging Derivatives Gain (Loss) Retiree Medical Plan Total Accumulated other comprehensive loss at April 2, 2016 $ (10,400 ) $ (297,768 ) $ 12,003 $ (296,165 ) Other comprehensive income (loss) before reclassifications 3,243 8,287 — 11,530 Amounts reclassified from accumulated other comprehensive income (loss) into earnings (2) 3,257 — — 3,257 Net current-period other comprehensive income (loss) 6,500 8,287 — 14,787 Accumulated other comprehensive loss at July 2, 2016 $ (3,900 ) $ (289,481 ) $ 12,003 $ (281,378 ) Six-Month July 2, 2016 Gains and Losses on Foreign Currency Adjustment to Early Hedging Derivatives Gain (Loss) Retiree Medical Plan Total Accumulated other comprehensive loss at December 31, 2015 $ (11,700 ) $ (351,665 ) $ 12,003 $ (351,362 ) Other comprehensive income (loss) before reclassifications 1,512 62,184 — 63,696 Amounts reclassified from accumulated other comprehensive income (loss) into earnings (2) 6,288 — — 6,288 Net current-period other comprehensive income (loss) 7,800 62,184 — 69,984 Accumulated other comprehensive loss at July 2, 2016 $ (3,900 ) $ (289,481 ) $ 12,003 $ (281,378 ) (2) Includes $3,257 and $6,288 of accumulated other comprehensive income reclassifications into cost of products sold for net losses on commodity contracts in the second quarter and first six months of 2016, respectively. The tax impacts of those reclassifications were $1,900 and $3,600, respectively.

Segments (Tables)

Segments (Tables)	6 Months Ended
	Jul. 01, 2017
Segment Reporting [Abstract]
Segments	Nucor’s results by segment were as follows (in thousands): Three Months (13 Weeks) Ended Six Months (26 Weeks) Ended July 1, 2017 July 2, 2016 July 1, 2017 July 2, 2016 Net sales to external customers: Steel mills $ 3,800,359 $ 3,016,322 $ 7,343,148 $ 5,650,911 Steel products 970,398 923,357 1,830,473 1,751,733 Raw materials 404,012 306,093 816,327 558,704 $ 5,174,769 $ 4,245,772 $ 9,989,948 $ 7,961,348 Intercompany sales: Steel mills $ 760,937 $ 554,395 $ 1,421,855 $ 1,024,658 Steel products 24,972 27,954 52,115 49,160 Raw materials 2,459,352 1,771,470 4,637,991 2,942,832 Corporate/eliminations (3,245,261 ) (2,353,819 ) (6,111,961 ) (4,016,650 ) $ — $ — $ — $ — Earnings (loss) before income taxes and noncontrolling interests: Steel mills $ 617,366 $ 530,727 $ 1,301,527 $ 811,099 Steel products 45,809 82,946 72,731 125,313 Raw materials 66,227 (27,181 ) 92,618 (90,553 ) Corporate/eliminations (221,266 ) (196,608 ) (409,765 ) (286,412 ) $ 508,136 $ 389,884 $ 1,057,111 $ 559,447 July 1, 2017 Dec. 31, 2016 Segment assets: Steel mills $ 9,230,612 $ 8,084,773 Steel products 2,691,020 2,544,344 Raw materials 3,316,269 3,235,237 Corporate/eliminations 874,824 1,359,164 $ 16,112,725 $ 15,223,518

Earnings Per Share (Tables)

Earnings Per Share (Tables)	6 Months Ended
	Jul. 01, 2017
Earnings Per Share [Abstract]
Computations of Basic and Diluted Net Earnings Per Share	The computations of basic and diluted net earnings per share are as follows (in thousands, except per share amounts): Three Months (13 Weeks) Ended Six Months (26 Weeks) Ended July 1, 2017 July 2, 2016 July 1, 2017 July 2, 2016 Basic net earnings per share: Basic net earnings $ 323,048 $ 243,620 $ 679,947 $ 331,185 Earnings allocated to participating securities (1,138 ) (852 ) (2,333 ) (1,089 ) Net earnings available to common stockholders $ 321,910 $ 242,768 $ 677,614 $ 330,096 Average shares outstanding 320,439 319,360 320,332 319,299 Basic net earnings per share $ 1.00 $ 0.76 $ 2.12 $ 1.03 Diluted net earnings per share: Diluted net earnings $ 323,048 $ 243,620 $ 679,947 $ 331,185 Earnings allocated to participating securities (1,136 ) (852 ) (2,328 ) (1,089 ) Net earnings available to common stockholders $ 321,912 $ 242,768 $ 677,619 $ 330,096 Diluted average shares outstanding: Basic shares outstanding 320,439 319,360 320,332 319,299 Dilutive effect of stock options and other 787 223 854 138 321,226 319,583 321,186 319,437 Diluted net earnings per share $ 1.00 $ 0.76 $ 2.11 $ 1.03
Anti-dilutive Stock Options	The following stock options were excluded from the computation of diluted net earnings per share because their effect would have been anti-dilutive (in thousands, except per share amounts): Three Months (13 Weeks) Ended Six Months (26 Weeks) Ended July 1, 2017 July 2, 2016 July 1, 2017 July 2, 2016 Anti-dilutive stock options: Weighted-average shares 698 1,334 349 1,874 Weighted-average exercise price $ 59.07 $ 49.40 $ 59.07 $ 47.04

Basis of Interim Presentation -

Basis of Interim Presentation - Additional Information (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jul. 01, 2017	Jul. 02, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Payment of tax withholdings on certain stock-based compensation	$ 13,185	$ 9,407

Basis of Interim Presentation39

Basis of Interim Presentation - Schedule of Adjustments to Condensed Consolidated Statement of Earnings (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 01, 2017	Jul. 02, 2016	Jul. 01, 2017	Jul. 02, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cost of products sold	$ 4,465,144	$ 3,660,512	$ 8,520,073	$ 7,061,103
Provision for income taxes	166,412	118,515	337,739	165,581
Net earnings	341,724	271,369	719,372	393,866
Earnings attributable to noncontrolling interests	18,676	27,749	39,425	62,681
Net earnings attributable to Nucor stockholders	323,048	243,620	679,947	331,185
Net earnings per share:
Cost of products sold	4,465,144	3,660,512	8,520,073	7,061,103
Provision for income taxes	166,412	118,515	337,739	165,581
Net earnings	341,724	271,369	719,372	393,866
Earnings attributable to noncontrolling interests	18,676	27,749	39,425	62,681
Net earnings attributable to Nucor stockholders	$ 323,048	$ 243,620	$ 679,947	$ 331,185
Basic	$ 1	$ 0.76	$ 2.12	$ 1.03
Diluted	$ 1	$ 0.76	$ 2.11	$ 1.03
As Originally Reported [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cost of products sold		$ 3,679,512		$ 7,108,140
Provision for income taxes		112,548		149,613
Net earnings		258,336		362,797
Earnings attributable to noncontrolling interests		24,564		58,271
Net earnings attributable to Nucor stockholders		233,772		304,526
Net earnings per share:
Cost of products sold		3,679,512		7,108,140
Provision for income taxes		112,548		149,613
Net earnings		258,336		362,797
Earnings attributable to noncontrolling interests		24,564		58,271
Net earnings attributable to Nucor stockholders		$ 233,772		$ 304,526
Basic		$ 0.73		$ 0.95
Diluted		$ 0.73		$ 0.95
Effect of Change [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cost of products sold		$ (19,000)		$ (47,037)
Provision for income taxes		5,967		15,968
Net earnings		13,033		31,069
Earnings attributable to noncontrolling interests		3,185		4,410
Net earnings attributable to Nucor stockholders		9,848		26,659
Net earnings per share:
Cost of products sold		(19,000)		(47,037)
Provision for income taxes		5,967		15,968
Net earnings		13,033		31,069
Earnings attributable to noncontrolling interests		3,185		4,410
Net earnings attributable to Nucor stockholders		$ 9,848		$ 26,659
Basic		$ 0.03		$ 0.08
Diluted		$ 0.03		$ 0.08

Basis of Interim Presentation40

Basis of Interim Presentation - Schedule of Adjustments to Condensed Consolidated Statement of Cash Flows (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 01, 2017	Jul. 02, 2016	Jul. 01, 2017	Jul. 02, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net earnings	$ 341,724	$ 271,369	$ 719,372	$ 393,866
Changes in inventories			(781,581)	(183,056)
Changes in deferred income taxes			$ (4,173)	11,687
As Originally Reported [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net earnings		258,336		362,797
Changes in inventories				(136,019)
Changes in deferred income taxes				(4,281)
Effect of Change [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net earnings		$ 13,033		31,069
Changes in inventories				(47,037)
Changes in deferred income taxes				$ 15,968

Acquisitions and Dispositions -

Acquisitions and Dispositions - Additional Information (Detail)	Jan. 20, 2017USD ($)FacilityT	Jan. 09, 2017USD ($)FacilityT	Jul. 01, 2017USD ($)	Jul. 02, 2016USD ($)	Dec. 31, 2016USD ($)
Business Acquisition [Line Items]
Goodwill			$ 2,179,641,000		$ 2,052,728,000
Republic [Member]
Business Acquisition [Line Items]
Business acquisition approximate purchase price	$ 331,600,000
Approximate annual shipment tons | T	146,000
Number of manufacturing facilities | Facility	2
Goodwill	$ 115,562,000
Other Acquisitions [Member]
Business Acquisition [Line Items]
Business acquisition approximate purchase price			150,800,000	$ 0
Southland [Member]
Business Acquisition [Line Items]
Business acquisition approximate purchase price		$ 130,000,000
Approximate annual shipment tons | T		240,000
Southland [Member] | Alabama [Member]
Business Acquisition [Line Items]
Number of manufacturing facilities | Facility		1
Steel Mills [Member]
Business Acquisition [Line Items]
Goodwill			$ 745,484,000		$ 620,156,000
Steel Mills [Member] | Republic [Member]
Business Acquisition [Line Items]
Goodwill	115,600,000
Goodwill expected to be deductible for tax purposes	$ 118,600,000

Acquisitions and Dispositions42

Acquisitions and Dispositions - Fair Values of Assets Acquired and Liabilities Assumed (Detail) - USD ($) $ in Thousands	Jul. 01, 2017	Jan. 20, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Goodwill	$ 2,179,641		$ 2,052,728
Republic [Member]
Business Acquisition [Line Items]
Cash		$ 206
Accounts receivable		39,177
Inventory		33,561
Other current assets		1,101
Property, plant and equipment		67,412
Goodwill		115,562
Other intangible assets		89,200
Other assets		3,118
Total assets acquired		349,337
Current liabilities		17,743
Total liabilities assumed		17,743
Net assets acquired		$ 331,594

Acquisitions and Dispositions43

Acquisitions and Dispositions - Purchase Price Allocation of Identifiable Intangible Assets (Detail) - Republic [Member] $ in Thousands	Jan. 20, 2017USD ($)
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets	$ 89,200
Customer Relationships [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets	$ 80,800
Weighted - Average Life	12 years
Trademarks and Trade Names [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets	$ 8,400
Weighted - Average Life	13 years

Accounts Receivable - Additiona

Accounts Receivable - Additional Information (Detail) - USD ($) $ in Millions	Jul. 01, 2017	Dec. 31, 2016
Accounts Receivable, Net [Abstract]
Allowance for doubtful accounts receivable	$ 47.3	$ 45.9

Inventories - Additional Inform

Inventories - Additional Information (Detail) - USD ($) $ in Millions	Jul. 01, 2017	Dec. 31, 2016
Inventory Disclosure [Abstract]
Raw materials and supplies in inventory, percentage	39.00%	37.00%
Finished and semi-finished products in inventory, percentage	61.00%	63.00%
Lower of cost or market adjustments	$ 2	$ 2.2

Property, Plant and Equipment -

Property, Plant and Equipment - Additional Information (Detail) - USD ($) $ in Thousands	Jul. 01, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Accumulated depreciation	$ 8,460,000	$ 8,160,000
Property, plant and equipment, net	5,062,423	5,078,650
Group Of Wells Assets With Carrying Value Closest To Its Undiscounted Cash Flows [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, net	$ 75,800	$ 80,800

Goodwill and Other Intangible47

Goodwill and Other Intangible Assets - Schedule of Change in Net Carrying Amount of Goodwill by Segment (Detail) $ in Thousands	6 Months Ended
	Jul. 01, 2017USD ($)
Goodwill [Line Items]
Balance, beginning of period	$ 2,052,728
Acquisitions	125,328
Translation	1,585
Balance, end of period	2,179,641
Steel Mills [Member]
Goodwill [Line Items]
Balance, beginning of period	620,156
Acquisitions	125,328
Balance, end of period	745,484
Steel Products [Member]
Goodwill [Line Items]
Balance, beginning of period	702,995
Translation	1,585
Balance, end of period	704,580
Raw Materials [Member]
Goodwill [Line Items]
Balance, beginning of period	729,577
Balance, end of period	$ 729,577

Goodwill and Other Intangible48

Goodwill and Other Intangible Assets - Additional Information (Detail) - USD ($)	3 Months Ended			6 Months Ended
	Jul. 01, 2017	Dec. 31, 2016	Jul. 02, 2016	Jul. 01, 2017	Jul. 02, 2016
Finite And Indefinite Lived Intangible Assets [Line Items]
Impairment of goodwill		$ 0
Intangible asset amortization expense	$ 23,000,000		$ 17,500,000	$ 45,400,000	$ 35,600,000
Future amortization expense, in 2017	90,800,000			90,800,000
Future amortization expense, in 2018	88,800,000			88,800,000
Future amortization expense, in 2019	85,900,000			85,900,000
Future amortization expense, in 2020	83,500,000			83,500,000
Future amortization expense, in 2021	$ 82,300,000			$ 82,300,000
Minimum [Member]
Finite And Indefinite Lived Intangible Assets [Line Items]
Intangible assets, useful life				5 years
Maximum [Member]
Finite And Indefinite Lived Intangible Assets [Line Items]
Intangible assets, useful life				22 years

Goodwill and Other Intangible49

Goodwill and Other Intangible Assets - Schedule of Intangible Assets (Detail) - USD ($) $ in Thousands	Jul. 01, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross Amount	$ 1,646,048	$ 1,520,461
Intangible assets, Accumulated Amortization	699,070	653,626
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross Amount	1,409,125	1,295,803
Intangible assets, Accumulated Amortization	603,734	566,884
Trademarks and Trade Names [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross Amount	174,116	161,851
Intangible assets, Accumulated Amortization	71,843	66,494
Other [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross Amount	62,807	62,807
Intangible assets, Accumulated Amortization	$ 23,493	$ 20,248

Equity Investments - Additional

Equity Investments - Additional Information (Detail) $ in Thousands, € in Millions	3 Months Ended		6 Months Ended
	Jul. 01, 2017USD ($)	Jul. 02, 2016USD ($)	Jul. 01, 2017USD ($)Sheet	Jul. 02, 2016USD ($)	Jul. 01, 2017EUR (€)	Dec. 31, 2016USD ($)	Dec. 31, 2016EUR (€)
Schedule of Equity Method Investments [Line Items]
Equity method investment	$ 679,500		$ 679,500			$ 663,400
Distributions from affiliates			46,877	$ 37,026
Amortization expense due to fair value step-up			45,443	35,587
NuMit LLC [Member]
Schedule of Equity Method Investments [Line Items]
Equity method investment	$ 302,300		$ 302,300			325,100
Equity method investment, ownership percentage	50.00%		50.00%		50.00%
Period used for lag basis, in months			1 month
Distributions from affiliates			$ 46,900	37,000
Steel Technologies LLC [Member]
Schedule of Equity Method Investments [Line Items]
Equity method investment, ownership percentage	100.00%		100.00%		100.00%
Number of sheet processing facilities operated by Steel Technologies | Sheet			25
Duferdofin Nucor S.r.l. [Member]
Schedule of Equity Method Investments [Line Items]
Equity method investment	$ 274,700		$ 274,700			256,600
Equity method investment, ownership percentage	50.00%		50.00%		50.00%
Period used for lag basis, in months			1 month
Equity method investments, share of net assets	$ 110,300		$ 110,300
Basis difference due to the step-up to fair value of certain assets and liabilities	164,400		164,400
Step-up to fair value of equity method investment, portion related to identification of goodwill	88,000
Amortization expense due to fair value step-up	2,200	$ 2,200	4,300	$ 4,400
Due from related parties, noncurrent	40,000		$ 40,000		€ 35	36,900	€ 35
Notes receivable, related parties, interest rate			0.94%
Interest rate per year in excess of Euribor as of date of the notes			1.00%
Equity method investments notes payable with parent company, maturity date			Jan. 31, 2019
Facility A [Member] | Duferdofin Nucor S.r.l. [Member]
Schedule of Equity Method Investments [Line Items]
Equity method investments credit facilities, amount	139,900		$ 139,900		122.5
Total amount outstanding under equity method investments credit facilities	$ 131,400		$ 131,400		€ 115	$ 112,700	€ 107
Guarantor obligation percentage of exposure in case of default	50.00%		50.00%		50.00%
Line of credit facility, maturity period			Oct. 12, 2018

Current Liabilities - Additiona

Current Liabilities - Additional Information (Detail) - USD ($) $ in Millions	Jul. 01, 2017	Dec. 31, 2016
Liabilities, Current [Abstract]
Book overdrafts	$ 123.5	$ 61.3
Dividends payable, current	$ 121.6	$ 121.3

Derivatives - Additional Inform

Derivatives - Additional Information (Detail) MMBTU in Millions	Jul. 01, 2017MMBTU
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Notional amount of commodity derivatives	17.6

Derivatives - Fair Value of Der

Derivatives - Fair Value of Derivative Instruments (Detail) - USD ($) $ in Thousands	Jul. 01, 2017	Dec. 31, 2016
Derivatives, Fair Value [Line Items]
Derivative Assets, Fair Value	$ 200	$ 2,029
Derivative Liabilities, Fair Value	(2,590)	(605)
Derivatives Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Liabilities, Fair Value	(1,890)	(605)
Commodity Contracts [Member] | Derivatives Designated as Hedging Instrument [Member] | Deferred Credits and Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liabilities, Fair Value	(700)
Commodity Contracts [Member] | Derivatives Designated as Hedging Instrument [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Assets, Fair Value	200	1,250
Commodity Contracts [Member] | Derivatives Not Designated as Hedging Instrument [Member] | Accrued Expenses and Other Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liabilities, Fair Value	(658)	(605)
Foreign Exchange Contracts [Member] | Derivatives Not Designated as Hedging Instrument [Member] | Accrued Expenses and Other Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liabilities, Fair Value	$ (1,232)
Foreign Exchange Contracts [Member] | Derivatives Not Designated as Hedging Instrument [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Assets, Fair Value		$ 779

Derivatives - Effect of Derivat

Derivatives - Effect of Derivative Instruments on Condensed Consolidated Statements of Earnings (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 01, 2017	Jul. 02, 2016	Jul. 01, 2017	Jul. 02, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss), net of tax, Recognized in OCI on Derivatives (Effective Portion)	$ (71)	$ 3,243	$ (1,706)	$ 1,512
Amount of Gain or (Loss), net of tax, Reclassified from Accumulated OCI into Earnings on Derivatives (Effective Portion)	(171)	(3,257)	(656)	(6,288)
Derivatives Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Recognized in Earnings on Derivatives	(1,813)	(975)	(5,264)	(1,705)
Cost of Products Sold [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss), net of tax, Reclassified from Accumulated OCI into Earnings on Derivatives (Effective Portion)	(171)	(3,257)	(656)	(6,288)
Cost of Products Sold [Member] | Commodity Contracts [Member] | Derivatives Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Recognized in Earnings on Derivatives	(364)	(962)	(2,919)	(874)
Cost of Products Sold [Member] | Commodity Contracts [Member] | Derivatives Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss), net of tax, Recognized in OCI on Derivatives (Effective Portion)	(71)	3,243	(1,706)	1,512
Amount of Gain or (Loss), net of tax, Reclassified from Accumulated OCI into Earnings on Derivatives (Effective Portion)	(171)	(3,257)	(656)	(6,288)
Amount of Gain or (Loss) net of tax, Recognized in Earnings on Derivatives (Ineffective Portion)	0	0	0	0
Cost of Products Sold [Member] | Foreign Exchange Contracts [Member] | Derivatives Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Recognized in Earnings on Derivatives	$ (1,449)	$ (13)	$ (2,345)	$ (831)

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Financial Assets and Liabilities Measured at Fair Value (Detail) - USD ($) $ in Thousands	Jul. 01, 2017	Dec. 31, 2016
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term investments	$ 50,000	$ 150,000
Commodity and foreign exchange contracts, assets	200	2,029
Total assets	16,112,725	15,223,518
Commodity and foreign exchange contracts, liabilities	(2,590)	(605)
Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents	1,092,015	1,609,523
Short-term investments	50,000	150,000
Commodity and foreign exchange contracts, assets	200	2,029
Total assets	1,142,215	1,761,552
Commodity and foreign exchange contracts, liabilities	(2,590)	(605)
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents	1,092,015	1,609,523
Short-term investments	50,000	150,000
Total assets	1,142,015	1,759,523
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	200	2,029
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring [Member] | Commodity Contracts And foreign Exchange Contracts [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity and foreign exchange contracts, assets		2,029
Commodity and foreign exchange contracts, liabilities	(2,590)
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring [Member] | Commodity Contracts [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity and foreign exchange contracts, assets	$ 200
Commodity and foreign exchange contracts, liabilities		$ (605)

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) - USD ($) $ in Millions	Jul. 01, 2017	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Fair value of short-term and long-term debt, including current maturities	$ 4,750	$ 4,700

Contingencies - Additional Info

Contingencies - Additional Information (Detail) - USD ($) $ in Millions	Jul. 01, 2017	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Accrual for environmental loss contingencies, gross	$ 17.4	$ 21.9
Accrued environmental loss contingencies, current	5.1	9.5
Accrued environmental loss contingencies, noncurrent	$ 12.3	$ 12.4

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jul. 01, 2017USD ($)	Jul. 02, 2016USD ($)	Jul. 01, 2017USD ($)$ / sharesAnniversariesInstallment	Jul. 02, 2016USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options exercise prices as percentage of the market value on the date of the grant			100.00%
Grant date fair value of stock options granted | $ / shares			$ 12.61
Compensation expenses for stock options	$ 7.2	$ 7.1	$ 7.5	$ 7.3
Restricted Stock [Member] | LTIP [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Portion of restricted stock award vesting on anniversary			0.333%
Eligible age of officer for restricted stock award			55 years
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense related to stock	46.3		$ 46.3
Weighted-average recognition period for unrecognized compensation expense related to stock (years)			2 years 6 months
Number of anniversaries of grant date upon which restricted stock units vest | Anniversaries			3
Installments in which restricted stock units vest and are converted to common stock | Installment			3
Compensation expense	21.1	18.3	$ 26.1	23.2
Restricted Stock Units [Member] | AIP [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Eligible age of officer for restricted stock award			55 years
Amount of annual incentive award payment participant can elect to defer			50.00%
Additional common stock units for election of deferred annual incentive award, percentage			25.00%
Restricted Stock And Restricted Stock Units [Member] | AIP and LTIP [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense related to stock	1.6		$ 1.6
Weighted-average recognition period for unrecognized compensation expense related to stock (years)			2 years 1 month 6 days
Compensation expense	3.2	$ 4.8	$ 7.5	$ 7
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options vesting period			3 years
Stock options term, years			10 years
Unrecognized compensation expense related to stock	$ 2.9		$ 2.9
Weighted-average recognition period for unrecognized compensation expense related to stock (years)			2 years 4 months 24 days

Stock-Based Compensation - Sche

Stock-Based Compensation - Schedule of Stock Option Plans Activity (Detail) $ / shares in Units, shares in Thousands, $ in Thousands	6 Months Ended
	Jul. 01, 2017USD ($)$ / sharesshares
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Outstanding at beginning of year, Shares | shares	3,591
Granted, Shares | shares	698
Exercised, Shares | shares	(92)
Canceled, Shares | shares	0
Outstanding at end of year, Shares | shares	4,197
Stock Options exercisable at end of year, Shares | shares	1,900
Outstanding at beginning of year, Weighted - Average Exercise Price | $ / shares	$ 45.32
Granted, Weighted - Average Exercise Price | $ / shares	59.07
Exercised, Weighted - Average Exercise Price | $ / shares	38.56
Canceled, Weighted - Average Exercise Price | $ / shares	0
Outstanding at end of period, Weighted - Average Exercise Price | $ / shares	47.75
Stock options exercisable at end of year, Weighted - Average Exercise Price | $ / shares	$ 43.16
Outstanding at end of period, Weighted - Average Remaining Contractual Life	7 years 3 months 19 days
Stock options exercisable at end of period, Weighted - Average Remaining Contractual Life	5 years 4 months 24 days
Exercised, Aggregate Intrinsic Value | $	$ 2,278
Outstanding at end of period, Aggregate Intrinsic Value | $	43,313
Stock options exercisable at end of period, Aggregate Intrinsic Value | $	$ 27,960

Stock-Based Compensation - Sc60

Stock-Based Compensation - Schedule of Grant Date Fair Value Black-Scholes Option-Pricing Model Assumptions (Detail)	6 Months Ended
	Jul. 01, 2017$ / shares
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Exercise price	$ 59.07
Expected dividend yield	2.56%
Expected stock price volatility	26.53%
Risk-free interest rate	2.02%
Expected life (years)	6 years 6 months

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Nucor's RSU Activity (Detail) shares in Thousands	6 Months Ended
	Jul. 01, 2017$ / sharesshares
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested at beginning of year, Shares	1,040
Granted, Shares	721
Vested, Shares	(630)
Canceled, Shares	(10)
Unvested at end of year, Shares	1,121
Unvested at beginning of year, Grant Date Fair Value | $ / shares	$ 48.47
Granted, Grant Date Fair Value | $ / shares	59.07
Vested, Grant Date Fair Value | $ / shares	53.21
Canceled, Grant Date Fair Value | $ / shares	49.38
Unvested at end of year, Grant Date Fair Value | $ / shares	$ 52.62
Restricted Stock Units and Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for future grants	7,278

Stock-Based Compensation - Su62

Stock-Based Compensation - Summary of Nucor's Restricted Stock Activity under AIP and LTIP (Detail) - Restricted Stock And Restricted Stock Units [Member] - AIP and LTIP [Member] shares in Thousands	6 Months Ended
	Jul. 01, 2017$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested at beginning of year, Shares	67
Granted, Shares	172
Vested, Shares	(144)
Canceled, Shares	0
Unvested at end of year, Shares	95
Shares reserved for future grants	683
Unvested at beginning of year, Grant Date Fair Value | $ / shares	$ 45.77
Granted, Grant Date Fair Value | $ / shares	60.62
Vested, Grant Date Fair Value | $ / shares	51.69
Canceled, Grant Date Fair Value | $ / shares	0
Unvested at end of year, Grant Date Fair Value | $ / shares	$ 54.45

Employee Benefit Plan - Additio

Employee Benefit Plan - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jul. 01, 2017	Jul. 02, 2016	Jul. 01, 2017	Jul. 02, 2016
Employee Benefit Plan [Abstract]
Profit Sharing and Retirement Savings Plan, plan expense	$ 48.5	$ 36	$ 102.5	$ 47.8

Interest Expense (Income) - Sch

Interest Expense (Income) - Schedule of Components of Net Interest Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 01, 2017	Jul. 02, 2016	Jul. 01, 2017	Jul. 02, 2016
Interest Revenue (Expense), Net [Abstract]
Interest expense	$ 47,565	$ 43,477	$ 93,865	$ 90,851
Interest income	(2,985)	(2,993)	(5,680)	(5,445)
Interest expense, net	$ 44,580	$ 40,484	$ 88,185	$ 85,406

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)	3 Months Ended
	Jul. 01, 2017	Jul. 02, 2016	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Effective income tax rate	32.70%	30.40%
Non-current deferred tax assets included in other assets	$ 600,000		$ 0
Non-current deferred tax liabilities included in deferred credits and other liabilities	$ 549,700,000		$ 558,600,000

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - USD ($)	Jul. 01, 2017	Sep. 02, 2015
Common Stock [Member]
Stockholders' Equity [Line Items]
Stock repurchase program remaining amount	$ 828,300,000
Common Stock [Member] | Maximum [Member]
Stockholders' Equity [Line Items]
Stock repurchase program authorized amount		$ 900,000,000
Nucor-Yamato Steel Company [Member]
Stockholders' Equity [Line Items]
Noncontrolling interest, ownership percentage by parent	51.00%

Stockholders' Equity - Schedule

Stockholders' Equity - Schedule of Change in Stockholder's Equity (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 01, 2017	Jul. 02, 2016	Jul. 01, 2017	Jul. 02, 2016
Stockholders' Equity [Line Items]
Stockholders' equity, beginning of period			$ 8,254,708	$ 7,849,877
Total comprehensive income	$ 365,781	$ 286,156	744,280	463,850
Stock options			11,068	9,215
Issuance of stock under award plans, net of forfeitures			23,593	18,973
Amortization of unearned compensation			700	500
Treasury stock acquired				(5,173)
Dividends declared			(243,016)	(240,538)
Distributions to noncontrolling interests			(79,420)	(78,684)
Other				(2,378)
Stockholders' equity, end of period	8,711,913	8,015,642	8,711,913	8,015,642
Total Nucor Stockholders' Equity [Member]
Stockholders' Equity [Line Items]
Stockholders' equity, beginning of period			7,879,865	7,477,816
Total comprehensive income			704,855	401,169
Stock options			11,068	9,215
Issuance of stock under award plans, net of forfeitures			23,593	18,973
Amortization of unearned compensation			700	500
Treasury stock acquired				(5,173)
Dividends declared			(243,016)	(240,538)
Other				(602)
Stockholders' equity, end of period	8,377,065	7,661,360	8,377,065	7,661,360
Noncontrolling Interests [Member]
Stockholders' Equity [Line Items]
Stockholders' equity, beginning of period			374,843	372,061
Total comprehensive income			39,425	62,681
Distributions to noncontrolling interests			(79,420)	(78,684)
Other				(1,776)
Stockholders' equity, end of period	$ 334,848	$ 354,282	$ 334,848	$ 354,282

Accumulated Other Comprehensi68

Accumulated Other Comprehensive Income (Loss) - Components of Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 01, 2017	Jul. 02, 2016	Jul. 01, 2017	Jul. 02, 2016
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Beginning Balance, Gains and Losses on Hedging Derivatives	$ (400)	$ (10,400)	$ 750	$ (11,700)
Other comprehensive income (loss) before reclassifications, Gains and Losses on Hedging Derivatives	(71)	3,243	(1,706)	1,512
Amounts reclassified from accumulated other comprehensive income (loss) into earnings, Gains and Losses on Hedging Derivatives	171	3,257	656	6,288
Net current-period other comprehensive income (loss), Gains and Losses on Hedging Derivatives	100	6,500	(1,050)	7,800
Ending Balance, Gains and Losses on Hedging Derivatives	(300)	(3,900)	(300)	(3,900)
Beginning Balance, Foreign Currency Gain (Loss)	(324,169)	(297,768)	(326,170)	(351,665)
Other comprehensive income (loss) before reclassifications, Foreign Currency Gain (Loss)	23,957	8,287	25,958	62,184
Amounts reclassified from accumulated other comprehensive income (loss) into earnings, Foreign Currency Gain (Loss)	0	0	0	0
Net current-period other comprehensive income (loss), Foreign Currency Gain (Loss)	23,957	8,287	25,958	62,184
Ending Balance, Foreign Currency Gain (Loss)	(300,212)	(289,481)	(300,212)	(289,481)
Beginning Balance, Adjustment to Early Retiree Medical Plan	7,577	12,003	7,577	12,003
Other comprehensive income (loss) before reclassifications, Adjustment to Early Retiree Medical Plan	0	0	0	0
Amounts reclassified from accumulated other comprehensive income (loss) into earnings, Adjustment to Early Retiree Medical Plan	0	0	0	0
Net current-period other comprehensive income (loss), Adjustment to Early Retiree Medical Plan	0	0	0	0
Ending Balance, Adjustment to Early Retiree Medical Plan	7,577	12,003	7,577	12,003
Beginning Balance, Accumulated Other Comprehensive Loss	(316,992)	(296,165)	(317,843)	(351,362)
Other comprehensive income (loss) before reclassifications	23,886	11,530	24,252	63,696
Amounts reclassified from accumulated other comprehensive income (loss) into earnings	171	3,257	656	6,288
Net current-period other comprehensive income (loss)	24,057	14,787	24,908	69,984
Ending Balance, Accumulated Other Comprehensive Loss	$ (292,935)	$ (281,378)	$ (292,935)	$ (281,378)

Accumulated Other Comprehensi69

Accumulated Other Comprehensive Income (Loss) - Components of Accumulated Other Comprehensive Income (Loss) (Parenthetical) (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 01, 2017	Jul. 02, 2016	Jul. 01, 2017	Jul. 02, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from accumulated other comprehensive income (loss) into earnings, Gains and Losses on Hedging Derivatives	$ 171	$ 3,257	$ 656	$ 6,288
AOCI reclassification impact on tax	0	1,900	300	3,600
Cost of Products Sold [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from accumulated other comprehensive income (loss) into earnings, Gains and Losses on Hedging Derivatives	171	3,257	656	6,288
AOCI reclassification impact on tax	$ 0	$ 1,900	$ 300	$ 3,600

Segments - Additional Informati

Segments - Additional Information (Detail)	3 Months Ended
	Oct. 01, 2016
Hunter Ridge Energy Services LLC [Member]
Segment Reporting Information [Line Items]
Equity method investment ownership percentage, percentage of investee's ownership interest sold	50.00%

Segments - Segments (Detail)

Segments - Segments (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 01, 2017	Jul. 02, 2016	Jul. 01, 2017	Jul. 02, 2016	Dec. 31, 2016
Segment Reporting Information [Line Items]
Net sales	$ 5,174,769	$ 4,245,772	$ 9,989,948	$ 7,961,348
Earnings (loss) before income taxes and noncontrolling interests	508,136	389,884	1,057,111	559,447
Total assets	16,112,725		16,112,725		$ 15,223,518
Operating Segments [Member] | Steel Mills [Member]
Segment Reporting Information [Line Items]
Net sales	3,800,359	3,016,322	7,343,148	5,650,911
Earnings (loss) before income taxes and noncontrolling interests	617,366	530,727	1,301,527	811,099
Total assets	9,230,612		9,230,612		8,084,773
Operating Segments [Member] | Steel Products [Member]
Segment Reporting Information [Line Items]
Net sales	970,398	923,357	1,830,473	1,751,733
Earnings (loss) before income taxes and noncontrolling interests	45,809	82,946	72,731	125,313
Total assets	2,691,020		2,691,020		2,544,344
Operating Segments [Member] | Raw Materials [Member]
Segment Reporting Information [Line Items]
Net sales	404,012	306,093	816,327	558,704
Earnings (loss) before income taxes and noncontrolling interests	66,227	(27,181)	92,618	(90,553)
Total assets	3,316,269		3,316,269		3,235,237
Intercompany Eliminations [Member] | Steel Mills [Member]
Segment Reporting Information [Line Items]
Net sales	760,937	554,395	1,421,855	1,024,658
Intercompany Eliminations [Member] | Steel Products [Member]
Segment Reporting Information [Line Items]
Net sales	24,972	27,954	52,115	49,160
Intercompany Eliminations [Member] | Raw Materials [Member]
Segment Reporting Information [Line Items]
Net sales	2,459,352	1,771,470	4,637,991	2,942,832
Corporate and Eliminations Items [Member]
Segment Reporting Information [Line Items]
Net sales	(3,245,261)	(2,353,819)	(6,111,961)	(4,016,650)
Earnings (loss) before income taxes and noncontrolling interests	(221,266)	$ (196,608)	(409,765)	$ (286,412)
Total assets	$ 874,824		$ 874,824		$ 1,359,164

Earnings Per Share - Computatio

Earnings Per Share - Computations of Basic and Diluted Net Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 01, 2017	Jul. 02, 2016	Jul. 01, 2017	Jul. 02, 2016
Earnings Per Share [Abstract]
Basic net earnings	$ 323,048	$ 243,620	$ 679,947	$ 331,185
Earnings allocated to participating securities, Basic	(1,138)	(852)	(2,333)	(1,089)
Net earnings available to common stockholders, Basic	$ 321,910	$ 242,768	$ 677,614	$ 330,096
Average shares outstanding	320,439	319,360	320,332	319,299
Basic net earnings per share	$ 1	$ 0.76	$ 2.12	$ 1.03
Diluted net earnings	$ 323,048	$ 243,620	$ 679,947	$ 331,185
Earnings allocated to participating securities, Diluted	(1,136)	(852)	(2,328)	(1,089)
Net earnings available to common stockholders, Diluted	$ 321,912	$ 242,768	$ 677,619	$ 330,096
Basic shares outstanding	320,439	319,360	320,332	319,299
Dilutive effect of stock options and other	787	223	854	138
Diluted average shares outstanding	321,226	319,583	321,186	319,437
Diluted net earnings per share	$ 1	$ 0.76	$ 2.11	$ 1.03

Earnings Per Share - Anti-dilut

Earnings Per Share - Anti-dilutive Stock Options (Detail) - $ / shares shares in Thousands	3 Months Ended		6 Months Ended
	Jul. 01, 2017	Jul. 02, 2016	Jul. 01, 2017	Jul. 02, 2016
Earnings Per Share [Abstract]
Weighted-average shares	698	1,334	349	1,874
Weighted-average exercise price	$ 59.07	$ 49.40	$ 59.07	$ 47.04