Nucor (NUE) 10-Q 12 Nov 14 2014 Q3 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	9 Months Ended
	Oct. 04, 2014
Document And Entity Information [Abstract]	'
Document Type	'10-Q
Amendment Flag	'false
Document Period End Date	4-Oct-14
Document Fiscal Year Focus	'2014
Document Fiscal Period Focus	'Q3
Trading Symbol	'NUE
Entity Registrant Name	'NUCOR CORP
Entity Central Index Key	'0000073309
Current Fiscal Year End Date	'--12-31
Entity Filer Category	'Large Accelerated Filer
Entity Common Stock, Shares Outstanding	318,999,937

Condensed_Consolidated_Stateme

Condensed Consolidated Statements of Earnings (Unaudited) (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Oct. 04, 2014	Sep. 28, 2013	Oct. 04, 2014	Sep. 28, 2013
Income Statement [Abstract]	'	'	'	'
Net sales	$5,701,869	$4,940,936	$16,101,388	$14,157,296
Costs, expenses and other:	'	'	'	'
Cost of products sold	5,102,283	4,532,393	14,708,733	13,132,412
Marketing, administrative and other expenses	152,604	125,126	418,851	364,501
Equity in earnings of unconsolidated affiliates	-2,352	-2,252	-10,028	-2,665
Interest expense, net	45,349	37,467	130,481	109,186
Costs, expenses and other, total	5,297,884	4,692,734	15,248,037	13,603,434
Earnings before income taxes and noncontrolling interests	403,985	248,202	853,351	553,862
Provision for income taxes	129,784	70,087	282,519	158,749
Net earnings	274,201	178,115	570,832	395,113
Earnings attributable to noncontrolling interests	28,754	30,518	67,313	77,582
Net earnings attributable to Nucor stockholders	$245,447	$147,597	$503,519	$317,531
Net earnings per share:	'	'	'	'
Basic	$0.76	$0.46	$1.57	$0.99
Diluted	$0.76	$0.46	$1.57	$0.99
Average shares outstanding:	'	'	'	'
Basic	320,023	319,341	319,737	318,979
Diluted	320,337	319,526	320,025	319,132
Dividends declared per share	$0.37	$0.37	$1.11	$1.10

Condensed_Consolidated_Stateme1

Condensed Consolidated Statements of Comprehensive Income (Unaudited) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Oct. 04, 2014	Sep. 28, 2013	Oct. 04, 2014	Sep. 28, 2013
Statement Of Comprehensive Income [Abstract]	'	'	'	'
Net earnings	$274,201	$178,115	$570,832	$395,113
Other comprehensive income (loss):	'	'	'	'
Net unrealized gain (loss) on hedging derivatives, net of income taxes of $100 and $0 for the third quarter of 2014 and 2013, respectively, and ($900) and $0 for the first nine months of 2014 and 2013, respectively	103	0	-1,530	0
Reclassification adjustment for loss on settlement of hedging derivatives included in net income, net of income taxes of $100 and $0 for the third quarter of 2014 and 2013, respectively, and $200 and $0 for the first nine months of 2014 and 2013, respectively	197	0	430	0
Foreign currency translation (loss) gain, net of income taxes of $0 and $500 for the third quarter of 2014 and 2013, respectively, and ($400) and $300 for the first nine months of 2014 and 2013, respectively	-81,689	31,879	-93,321	-34,216
Net current-period other comprehensive (loss) income	-81,389	31,879	-94,421	-34,216
Comprehensive income	192,812	209,994	476,411	360,897
Comprehensive income attributable to noncontrolling interests	-28,754	-30,518	-67,313	-77,582
Comprehensive income attributable to Nucor stockholders	$164,058	$179,476	$409,098	$283,315

Condensed_Consolidated_Stateme2

Condensed Consolidated Statements of Comprehensive Income (Unaudited) (Parenthetical) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Oct. 04, 2014	Sep. 28, 2013	Oct. 04, 2014	Sep. 28, 2013
Statement Of Comprehensive Income [Abstract]	'	'	'	'
Net unrealized gain (loss) on hedging derivatives, tax effect	$100	$0	($900)	$0
Reclassification adjustment for loss on settlement of hedging derivatives included in net earnings, tax effect	100	0	200	0
Foreign currency translation (loss) gain, tax effect	$0	$500	($400)	$300

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (Unaudited) (USD $)	Oct. 04, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Current assets:	'	'
Cash and cash equivalents	$1,295,945	$1,483,252
Short-term investments	100,000	28,191
Accounts receivable, net	2,243,908	1,810,987
Inventories, net	2,683,235	2,605,609
Other current assets	473,156	482,007
Total current assets	6,796,244	6,410,046
Property, plant and equipment, net	4,884,010	4,917,024
Goodwill	1,982,776	1,973,608
Other intangible assets, net	819,078	874,154
Other assets	1,011,486	1,028,451
Total assets	15,493,594	15,203,283
Current liabilities:	'	'
Short-term debt	41,101	29,202
Long-term debt due within one year	16,300	3,300
Accounts payable	1,113,284	1,117,078
Federal income taxes payable	65,096	0
Salaries, wages and related accruals	341,875	282,860
Accrued expenses and other current liabilities	578,840	527,776
Total current liabilities	2,156,496	1,960,216
Long-term debt due after one year	4,360,600	4,376,900
Deferred credits and other liabilities	960,795	955,889
Total liabilities	7,477,891	7,293,005
Nucor stockholders' equity:	'	'
Common stock	151,227	151,010
Additional paid-in capital	1,876,728	1,843,353
Retained earnings	7,287,500	7,140,440
Accumulated other comprehensive (loss) income, net of income taxes	-85,341	9,080
Treasury stock	-1,494,832	-1,498,114
Total Nucor stockholders' equity	7,735,282	7,645,769
Noncontrolling interests	280,421	264,509
Total equity	8,015,703	7,910,278
Total liabilities and equity	$15,493,594	$15,203,283

Condensed_Consolidated_Stateme3

Condensed Consolidated Statements of Cash Flows (Unaudited) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Oct. 04, 2014	Sep. 28, 2013
Operating activities:	'	'
Net earnings	$570,832	$395,113
Adjustments:	'	'
Depreciation	486,684	390,495
Amortization	54,127	56,051
Stock-based compensation	40,325	40,551
Deferred income taxes	-43,712	10,881
Distributions from affiliates	11,504	7,708
Equity in earnings of unconsolidated affiliates	-10,028	-2,665
Loss on assets	21,546	14,000
Changes in assets and liabilities (exclusive of acquisitions and dispositions):	'	'
Accounts receivable	-418,353	-204,540
Inventories	-80,975	-129,280
Accounts payable	84,161	122,520
Federal income taxes	94,999	70,210
Salaries, wages and related accruals	65,027	12,796
Other operating activities	49,426	99,800
Cash provided by operating activities	925,563	883,640
Investing activities:	'	'
Capital expenditures	-557,249	-887,929
Investment in and advances to affiliates	-94,128	-64,762
Repayment of advances to affiliates	26,500	42,000
Disposition of plant and equipment	18,748	29,328
Acquisitions (net of cash acquired)	-38,466	0
Purchases of investments	-100,000	-19,349
Proceeds from the sale of investments	27,529	73,428
Proceeds from the sale of restricted investments	0	148,725
Changes in restricted cash	0	126,045
Other investing activities	0	4,862
Cash used in investing activities	-717,066	-547,652
Financing activities:	'	'
Net change in short-term debt	11,900	8,331
Proceeds from long-term debt, net of discount	0	999,100
Repayment of long-term debt	-3,300	-250,000
Bond issuance costs	0	-7,625
Issuance of common stock	4,465	0
Excess tax benefits from stock-based compensation	3,200	2,100
Distributions to noncontrolling interests	-51,401	-63,318
Cash dividends	-356,230	-353,155
Other financing activities	-1,651	110
Cash (used in) provided by financing activities	-393,017	335,543
Effect of exchange rate changes on cash	-2,787	-1,484
(Decrease) increase in cash and cash equivalents	-187,307	670,047
Cash and cash equivalents - beginning of year	1,483,252	1,052,862
Cash and cash equivalents - end of nine months	1,295,945	1,722,909
Non-cash investing activity:	'	'
Change in accrued plant and equipment purchases	($98,050)	($30,416)

BASIS_OF_INTERIM_PRESENTATION

BASIS OF INTERIM PRESENTATION	9 Months Ended
	Oct. 04, 2014
[BasisOfInterimPresentationAbstract]	'
BASIS OF INTERIM PRESENTATION	'
	1	BASIS OF INTERIM PRESENTATION: The information furnished in 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, 2013 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 consolidated financial statements and the notes thereto included in Nucor’s Annual Report on Form 10-K for the fiscal year ended December 31, 2013.
		Recently Adopted Accounting Pronouncements — In the first quarter of 2014, Nucor adopted new accounting guidance, which requires unrecognized tax benefits to be presented as a decrease in net operating loss, similar tax loss or tax credit carryforward if certain criteria are met. Adoption of the guidance did not impact Nucor’s consolidated financial position, results of operations or cash flows.
	In March 2013, new accounting guidance was issued on foreign currency matters that clarifies the guidance of a parent company’s accounting for the cumulative translation adjustment upon derecognition of certain subsidiaries or groups of assets within a foreign entity or of an investment in a foreign entity. Under this new standard, a parent company that ceases to have a controlling financial interest in a foreign subsidiary or group of assets within a foreign entity shall release any related cumulative translation adjustment into net income only if a sale or transfer results in complete or substantially complete liquidation of the foreign entity. This standard is applied prospectively for the Company beginning January 1, 2014. The adoption of this standard did not have a material effect on the consolidated financial statements.
	In February 2013, new accounting guidance was issued on joint and several liability arrangements for which the total amount of the obligation is fixed at the reporting date. Under this new standard, obligations resulting from joint and several liability arrangements are to be measured as the sum of: (a) the amount the reporting entity agreed with its co-obligors that it will pay and (b) any additional amount the reporting entity expects to pay on behalf of its co-obligors. This standard is applied prospectively for the Company beginning January 1, 2014. The adoption of this standard did not have a material effect on the consolidated financial statements.
		Recently Issued Accounting Pronouncements — In April 2014, new accounting guidance was issued which changes the criteria for determining which disposals can be presented as discontinued operations and modifies related disclosure requirements. The new guidance is effective for annual and interim periods beginning after December 15, 2014. The impact on the Company of adopting the new guidance will depend on the nature, terms and size of business disposals completed after the effective date.
	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 amendments are effective for the Company for all annual and interim reporting periods beginning after December 15, 2016. The Company is currently evaluating adoption methods and the impact it will have on the consolidated financial statements.
	In August 2014, new accounting guidance was issued that specifies the responsibility that an entity’s management has to evaluate whether there is substantial doubt about the entity’s ability to continue as a going concern. The standard is effective for interim and annual periods beginning after December 15, 2016, and is not expected to have an effect on the Company’s financial statements.

ACCOUNTS_RECEIVABLE

ACCOUNTS RECEIVABLE	9 Months Ended
	Oct. 04, 2014
Accounts Receivable, Net [Abstract]	'
ACCOUNTS RECEIVABLE	'
	2	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 $62.1 million at October 4, 2014 ($58.3 million at December 31, 2013).

INVENTORIES

INVENTORIES	9 Months Ended
	Oct. 04, 2014
Inventory Disclosure [Abstract]	'
INVENTORIES	'
	3	INVENTORIES: Inventories consisted of approximately 40% raw materials and supplies and 60% finished and semi-finished products at October 4, 2014 and at December 31, 2013. 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.
	Inventories valued using the last-in, first-out (LIFO) method of accounting represented approximately 46% of total inventories as of October 4, 2014 (45% as of December 31, 2013). If the first-in, first-out (FIFO) method of accounting had been used, inventories would have been $624.7 million higher at both October 4, 2014 and December 31, 2013. Use of the lower of cost or market methodology reduced inventories by $2.6 million at October 4, 2014 ($2.1 million at December 31, 2013).

PROPERTY_PLANT_AND_EQUIPMENT

PROPERTY, PLANT AND EQUIPMENT	9 Months Ended
	Oct. 04, 2014
Property, Plant and Equipment [Abstract]	'
PROPERTY, PLANT AND EQUIPMENT	'
	4	PROPERTY, PLANT AND EQUIPMENT: Property, plant and equipment is recorded net of accumulated depreciation of $7.07 billion at October 4, 2014 ($6.63 billion at December 31, 2013).
	Included within property, plant and equipment, net at October 4, 2014 is $23.5 million of assets, net of accumulated depreciation, under a capital lease agreement (none at December 31, 2013). The gross amount of property, plant and equipment acquired under the capital lease was $25.4 million, which is not included in capital expenditures on the condensed consolidated statement of cash flows. Total obligations associated with this capital lease agreement were $23.7 million at October 4, 2014 (none at December 31, 2013), of which $2.2 million was classified in accrued expenses and other current liabilities and $21.5 million was classified in deferred credits and other liabilities.
	In the third quarter of 2013, one of three iron ore storage domes collapsed at Nucor Steel Louisiana in St. James Parish. As a result, Nucor recorded a partial write down of assets at the facility, including $21.0 million of property, plant and equipment and $7.0 million of inventory, offset by a $14.0 million insurance receivable that was based on management’s current estimate of probable insurance recoveries. The associated net charge of $14.0 million was included in marketing, administrative and other expenses in the consolidated statement of earnings in 2013. The two remaining storage domes have a carrying value of approximately $21 million. Nucor continues to assess these two domes and the assets associated with them. As a result of the ongoing assessment, it is possible that Nucor will make operational decisions that could impact the carrying value of the domes and associated assets and the amount of insurance proceeds received.

RESTRICTED_CASH_AND_INVESTMENT

RESTRICTED CASH AND INVESTMENTS	9 Months Ended
	Oct. 04, 2014
Restricted Cash And Investments [Abstract]	'
RESTRICTED CASH AND INVESTMENTS	'
	5	RESTRICTED CASH AND INVESTMENTS: There were no restricted cash or investments as of October 4, 2014 or December 31, 2013. In November 2010, Nucor issued $600.0 million in 30-year Gulf Opportunity Zone bonds, the net proceeds of which were accounted for as restricted cash and investments. The restricted cash and investments were held in a trust account and were used to partially fund the capital costs associated with the construction of Nucor’s direct reduced ironmaking facility in St. James Parish, Louisiana. Funds were disbursed as qualified expenditures for the construction of the facility were made, with $274.9 million being disbursed in the first nine months of 2013. The remaining funds were disbursed over the remainder of 2013.

GOODWILL_AND_OTHER_INTANGIBLE_

GOODWILL AND OTHER INTANGIBLE ASSETS	9 Months Ended
	Oct. 04, 2014
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 nine months ended October 4, 2014 by segment is as follows (in thousands):
			Steel Mills		Steel Products			Raw Materials		Total
	Balance at December 31, 2013		$	495,897	$	774,486		$	703,225	$	1,973,608
	Other			—		311			26,352		26,663
	Translation			—		(17,495	)		—		(17,495	)
	Balance at October 4, 2014		$	495,897	$	757,302		$	729,577	$	1,982,776
	Goodwill increased by $26.4 million in the third quarter of 2014 due to a correction of deferred taxes related to purchase accounting for the acquisition of The David J. Joseph Company in 2008. This correction did not have an impact on the condensed consolidated statements of earnings, condensed consolidated statements of comprehensive income and the condensed consolidated statements of cash flows in the periods presented and in prior years. Also, this correction had no impact on the results of the goodwill impairment assessments performed in prior periods.
	Nucor completed its most recent annual goodwill impairment testing during the fourth quarter of 2013 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 were comprised of the following (in thousands):
			Oct. 4, 2014					Dec. 31, 2013
			Gross		Accumulated			Gross		Accumulated
			Amount		Amortization			Amount		Amortization
	Customer relationships		$	1,146,859	$	438,649		$	1,147,786	$	391,254
	Trademarks and trade names			150,355		46,100			151,332		40,397
	Other			22,823		16,210			21,869		15,182
			$	1,320,037	$	500,959		$	1,320,987	$	446,833
	Intangible asset amortization expense in the third quarter of 2014 and 2013 was $17.9 million and $18.5 million, respectively, and was $54.1 million and $56.1 million in the first nine months of 2014 and 2013, respectively. Annual amortization expense is estimated to be $71.4 million in 2014; $68.6 million in 2015; $66.9 million in 2016; $65.2 million in 2017; and $61.5 million in 2018.

EQUITY_INVESTMENTS

EQUITY INVESTMENTS	9 Months Ended
	Oct. 04, 2014
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 $923.2 million at October 4, 2014 ($936.0 million at December 31, 2013) and is recorded in other assets in the condensed consolidated balance sheets.
	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 lag basis) under the equity method, as control and risk of loss are shared equally between the members.
	Nucor’s investment in Duferdofin Nucor at October 4, 2014 was $431.0 million ($465.4 million at December 31, 2013). Nucor’s 50% share of the total net assets of Duferdofin Nucor was $58.9 million at October 4, 2014, resulting in a basis difference of $372.1 million due to the step-up to fair value of certain assets and liabilities attributable to Duferdofin Nucor as well as the identification of goodwill ($302.2 million) and finite-lived intangible assets. This basis difference, excluding the portion attributable to goodwill, is being amortized based on the remaining estimated useful lives of the various underlying net assets, as appropriate. Amortization expense and other purchase accounting adjustments associated with the fair value step-up were $2.6 million and $2.8 million in the third quarter of 2014 and 2013, respectively, and were $8.0 million and $8.5 million in the first nine months of 2014 and 2013, respectively.
	As of October 4, 2014, Nucor had outstanding notes receivable of €35.0 million ($43.8 million) from Duferdofin Nucor (€35.0 million, or $48.2 million, at December 31, 2013). The notes receivable bear interest at 1.34% and reset annually on September 30 to the twelve-month Euro Interbank Offered Rate (Euribor) plus 1% per year. The principal amounts are due on January 31, 2016. Accordingly, the notes receivable were classified in other assets on the condensed consolidated balance sheets as of October 4, 2014.
	Nucor has issued guarantees for its ownership percentage (50%) of Duferdofin Nucor’s borrowings under Facility A of a Structured Trade Finance Facilities Agreement as well as the Standby Medium Long Term Loan Credit Facility, which mature on April 26, 2016 and April 22, 2016, respectively. The maximum amount that Duferdofin Nucor can borrow under Facility A is €122.5 million, and as of October 4, 2014, Duferdofin Nucor had €105.0 million ($131.4 million) outstanding under that facility (€112.0 million, or $154.4 million, at December 31, 2013). The guarantee under the Standby Medium Long Term Loan Credit Facility was issued in the second quarter of 2014, and as of October 4, 2014, Duferdofin Nucor had the maximum borrowing amount of €60.0 million ($75.1 million) outstanding under that facility. If Duferdofin Nucor fails to pay when due any amounts for which it is obligated under Facility A or the Standby Medium Long Term Credit Facility, Nucor could be required to pay 50% of such amounts pursuant to and in accordance with the terms of its guarantees. Any indebtedness of Duferdofin Nucor to Nucor is effectively subordinated to the indebtedness of Duferdofin Nucor under both financing agreements. Nucor has not recorded any liability associated with these guarantees.
	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 U.S., Canada and Mexico. Nucor accounts for the investment in NuMit (on a one-month lag basis) under the equity method as control and risk of loss are shared equally between the members.
	Nucor’s investment in NuMit at October 4, 2014 was $334.9 million ($318.4 million as of December 31, 2013). Nucor has recorded two notes receivable from Steel Technologies LLC. The first note receivable of $40.0 million bears interest at 1.13% as of October 4, 2014, and it resets quarterly to the three-month London Interbank Offered Rate (LIBOR) plus 90 basis points. Steel Technologies, LLC paid this note subsequent to the balance sheet date with additional funds drawn from the line of credit discussed below. The second note receivable of $44.0 million was issued on May 2, 2014. It bears interest at 1.44% as of October 4, 2014 and matures May 1, 2015. In addition, Nucor has extended a $60.0 million line of credit (of which $8.5 million was outstanding at October 4, 2014) to Steel Technologies LLC. As of October 4, 2014, the amounts outstanding on the line of credit bear interest at 1.34% and mature on April 1, 2015. As of October 4, 2014, both the notes receivable and the amounts outstanding on the line of credit are classified in other current assets in the condensed consolidated balance sheets.
	HUNTER RIDGE
	Nucor has a 50% economic and voting interest in Hunter Ridge Energy Services LLC (Hunter Ridge). Hunter Ridge provides services for the gathering, separation and compression of energy products including natural gas produced by Nucor’s working interest drilling program. Nucor accounts for the investment (on a one-month lag basis) under the equity method, as control and risk of loss are shared equally between the members. Nucor’s investment in Hunter Ridge at October 4, 2014 was $137.9 million ($134.5 million at December 31, 2013).
	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. In the fourth quarter of 2013, Nucor assessed its equity investment in Duferdofin Nucor for impairment due to the protracted challenging steel market conditions in Europe. After completing its assessment, the Company determined that the estimated fair value exceeded its carrying amount and that there was no need for impairment. The assumptions that most significantly affect the fair value determination include projected revenues and the discount rate. Steel market conditions in Europe have continued to be challenging through the first nine months of 2014, and, 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. Nucor recorded a $30.0 million impairment charge against its investment in Duferdofin Nucor in the second quarter of 2012.

CURRENT_LIABILITIES

CURRENT LIABILITIES	9 Months Ended
	Oct. 04, 2014
Liabilities, Current [Abstract]	'
CURRENT LIABILITIES	'
	8	CURRENT LIABILITIES: Book overdrafts, included in accounts payable in the condensed consolidated balance sheets, were $118.2 million at October 4, 2014 ($81.6 million at December 31, 2013). Dividends payable, included in accrued expenses and other current liabilities in the condensed consolidated balance sheets, were $118.9 million at October 4, 2014 ($118.7 million at December 31, 2013).

DERIVATIVES

DERIVATIVES	9 Months Ended
	Oct. 04, 2014
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 October 4, 2014, natural gas swaps covering approximately 16.0 million MMBTUs (extending through February 2017) 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	Oct. 4,			Dec. 31,
				2014			2013
	Asset derivatives not designated as hedging instruments:
	Commodity contracts		Other current assets	$	1,384		$	—
	Foreign exchange contracts		Other current assets		57			—
	Total asset derivatives			$	1,441		$	—
	Liability derivatives designated as hedging instruments:
	Commodity contracts		Accrued expenses and other current liabilities		(1,700	)		—
	Commodity contracts		Deferred credits and other liabilities		(100	)		—
	Total Liability derivatives designated as hedging instruments				(1,800	)		—
	Liability derivatives not designated as hedging instruments:
	Commodity contracts		Accrued expenses and other current liabilities		—			(553	)
	Foreign exchange contracts		Accrued expenses and other current liabilities		—			(2	)
	Total liability derivatives not designated as hedging instruments				—			(555	)
	Total liability derivatives			$	(1,800	)	$	(555	)
	The Effect of Derivative Instruments on the Condensed Consolidated Statements of Earnings
	Derivatives Designated as Hedging Instruments
	Derivatives in Cash Flow Hedging		Statement of	Amount of Gain						Amount of Gain					Amount of Gain
	Relationships		Earnings Location	or (Loss),						or (Loss),					or (Loss),
				net of tax,						net of tax,					net of tax,
				Recognized in OCI						Reclassified from					Recognized in
				on Derivatives						Accumulated OCI  into					Earnings on
				(Effective Portion)						Earnings					Derivatives
										(Effective Portion)					(Ineffective Portion)
				Three Months						Three Months					Three Months
				(13 weeks) Ended						(13 weeks) Ended					(13 weeks) Ended
				Oct. 4, 2014			Sept. 28, 2013			Oct. 4, 2014			Sept. 28, 2013		Oct. 4, 2014		Sept. 28, 2013
	Commodity contracts		Cost of products sold	$	103		$	—		$	(197	)	$	—	$	—	$	—
	Derivatives in Cash Flow Hedging		Statement of	Amount of Gain						Amount of Gain					Amount of Gain
	Relationships		Earnings Location	or (Loss),						or (Loss),					or (Loss),
				net of tax,						net of tax,					net of tax,
				Recognized in OCI						Reclassified from					Recognized in
				on Derivatives						Accumulated OCI  into					Earnings on
				(Effective Portion)						Earnings					Derivatives
										(Effective Portion)					(Ineffective Portion)
				Nine Months						Nine Months					Nine Months
				(39 weeks) Ended						(39 weeks) Ended					(39 weeks) Ended
				Oct. 4, 2014			Sept. 28, 2013			Oct. 4, 2014			Sept. 28, 2013		Oct. 4, 2014		Sept. 28, 2013
	Commodity contracts		Cost of products sold	$	(1,530	)	$	—		$	(430	)	$	—	$	—	$	—
	Derivatives Not Designated as Hedging Instruments
	Derivatives Not Designated as		Statement of	Amount of Gain or (Loss) Recognized in Earnings on Derivatives
	Hedging Instruments		Earnings Location	Three Months (13 weeks) Ended						Nine Months (39 weeks) Ended
				Oct. 4,			Sept. 28,			Oct. 4,			Sept. 28,
				2014			2013			2014			2013
	Commodity contracts		Cost of products sold	$	844		$	(789	)	$	1,282		$	4,193
	Foreign exchange contracts		Cost of products sold		314			134			266			253
	Total			$	1,158		$	(655	)	$	1,548		$	4,446

FAIR_VALUE_MEASUREMENTS

FAIR VALUE MEASUREMENTS	9 Months Ended
	Oct. 04, 2014
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 were measured at fair value as of October 4, 2014 and December 31, 2013 (in thousands). Nucor does not currently have any non-financial assets or liabilities that are measured at fair value on a recurring basis.
						Fair Value Measurements at Reporting Date Using
	Description		Carrying			Quoted Prices		Significant			Significant
			Amount in			in Active		Other			Unobservable
			Condensed			Markets for		Observable			Inputs
			Consolidated			Identical		Inputs			(Level 3)
			Balance Sheets			Assets		(Level 2)
						(Level 1)
	As of October 4, 2014
	Assets:
	Cash equivalents		$	1,140,092		$	1,140,092	$	—		$	—
	Short-term investments			100,000			100,000		—			—
	Foreign exchange and commodity contracts			1,441			—		1,441			—
	Total assets		$	1,241,533		$	1,240,092	$	1,441		$	—
	Liabilities:
	Commodity contracts		$	(1,800	)	$	—	$	(1,800	)	$	—
	As of December 31, 2013
	Assets:
	Cash equivalents		$	1,269,465		$	1,269,465	$	—		$	—
	Short-term investments			28,191			28,191		—			—
	Total assets		$	1,297,656		$	1,297,656	$	—		$	—
	Liabilities:
	Foreign exchange and commodity contracts		$	(555	)	$	—	$	(555	)	$	—
	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 Nucor’s annual report for the year ended December 31, 2013. Fair value measurements for Nucor’s derivatives are classified under Level 2 because such measurements are based on published market prices for similar assets or are estimated based on observable inputs such as interest rates, yield curves, credit risks, spot and future commodity prices, and spot and future exchange rates.
	The fair value of short-term and long-term debt, including current maturities, was approximately $4.78 billion at October 4, 2014 ($4.61 billion at December 31, 2013). The debt fair value estimates are classified under Level 2 because such estimates are based on readily available market prices of our debt at October 4, 2014 and December 31, 2013, or similar debt with the same maturities, rating and interest rates.

CONTINGENCIES

CONTINGENCIES	9 Months Ended
	Oct. 04, 2014
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 $19.3 million of accrued environmental costs at October 4, 2014 ($22.9 million at December 31, 2013), $4.7 million was classified in accrued expenses and other current liabilities ($6.9 million at December 31, 2013) and $14.6 million was classified in deferred credits and other liabilities ($16.0 million at December 31, 2013). Inherent uncertainties exist in these estimates primarily due to unknown conditions, evolving remediation technology, and changing governmental regulations and legal standards.
	Nucor has been named, along with other major steel producers, as a co-defendant in several related antitrust class-action complaints filed by Standard Iron Works and other steel purchasers in the United States District Court for the Northern District of Illinois. The majority of these complaints were filed in September and October of 2008, with two additional complaints being filed in July and December of 2010. Two of these complaints have been voluntarily dismissed and are no longer pending. The plaintiffs allege that from April 1, 2005 through December 31, 2007, eight steel manufacturers, including Nucor, engaged in anticompetitive activities with respect to the production and sale of steel. The plaintiffs seek monetary and other relief. Five of the eight defendants have reached court approved settlements with the plaintiffs. Although we believe the plaintiffs’ claims are without merit, we will continue to vigorously defend against them, but we cannot at this time predict the outcome of this litigation or estimate the range of Nucor’s potential exposure.
	On March 25, 2014, a jury in the U.S. District Court for the Southern District of Texas returned a verdict against Nucor and its co-defendants in an antitrust lawsuit brought by plaintiff MM Steel, LP, a steel plate service center located in Houston. The jury returned a verdict of $52.0 million in damages against all defendants jointly and severally. On June 1, 2014, pursuant to antitrust laws providing for treble damages, the court awarded a judgment to MM Steel jointly and severally against the defendants in an amount totaling $160.8 million after including costs and attorneys’ fees. The Company has appealed the judgment to the U.S. Court of Appeals for the Fifth Circuit, and believes that it has valid grounds to have the judgment vacated or reversed. The Company believes that the evidence against Nucor was insufficient to support any finding that Nucor was involved in a horizontal conspiracy. The Company believes that the trial court wrongly excluded relevant testimony of Nucor’s expert witness. The Company believes that the trial court erred in admitting hearsay evidence. Finally, the Company believes that the trial court did not sufficiently instruct the jury on applicable legal principles. As a result, the Company believes that the likelihood that the judgment will be affirmed is not probable, and, accordingly, it has not recorded any reserves or contingencies related to this legal matter. Although we are defending this lawsuit vigorously, its ultimate resolution is uncertain.
	We are from time to time a party to various other lawsuits, claims and 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.

STOCKBASED_COMPENSATION

STOCK-BASED COMPENSATION	9 Months Ended
	Oct. 04, 2014
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 directors with exercise prices at 100% of the market value on the date of the grant. The stock options granted are generally exercisable at the end of three years and have a term of 10 years. New shares are issued upon exercise of stock options.
	A summary of activity under Nucor’s stock option plans for the first nine months of 2014 is as follows (in thousands, except year and per share amounts):
			Shares			Weighted -		Weighted -		Aggregate
						Average		Average		Intrinsic
						Exercise		Remaining		Value
						Price		Contractual Life
	Number of shares under option:
	Outstanding at beginning of year			2,089		$	40.47
	Granted			469		$	50.63
	Exercised			(112	)	$	40.01			$	1,891
	Canceled			—			—
	Outstanding at October 4, 2014			2,446		$	42.43		7.7 years	$	23,349
	Options exercisable at October 4, 2014			1,287		$	40.53		6.7 years	$	14,744
	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 are not retirement-eligible is recognized on a straight-line basis over the vesting period. Compensation expense for stock options was $0.1 million in the third quarter of 2014 (none in the third quarter of 2013), and $7.7 million and $8.6 million in the first nine months of 2014 and 2013, respectively. As of October 4, 2014, unrecognized compensation expense related to options was $0.5 million, which is expected to be recognized over 2.7 years.
		Restricted Stock Units – Nucor annually grants restricted stock units (RSUs) to key employees, officers and non-employee directors. The RSUs typically vest and are converted to common stock in three equal installments on each of the first three anniversaries of the grant date. A portion of the RSUs awarded to senior officers vest upon the officer’s retirement. Retirement, for purposes of vesting in these units only, means termination of employment with approval of the Compensation and Executive Development Committee of the Board of Directors after satisfying age and years of service requirements. RSUs granted to non-employee directors are fully vested on the grant date and are payable to the non-employee director in the form of common stock after the termination of the director’s service on the board of directors.
	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 are not retirement-eligible is recognized on a straight-line basis over the vesting period.
	Cash dividend equivalents are paid to participants each quarter. Dividend equivalents paid on units expected to vest are recognized as a reduction in retained earnings.
	The fair value of the RSUs is determined based on the closing stock price of Nucor’s common stock on the day before the grant. A summary of Nucor’s RSU activity for the first nine months of 2014 is as follows (shares in thousands):
			Shares			Grant Date
						Fair Value
	Restricted stock units:
	Unvested at beginning of year			1,122		$	42.51
	Granted			655		$	50.63
	Vested			(749	)	$	44.9
	Canceled			(13	)	$	42.66
	Unvested at October 4, 2014			1,015		$	45.98
	Shares reserved for future grants (stock options and RSUs)			11,860
	Compensation expense for RSUs was $5.3 million in the third quarter of both 2014 and 2013, respectively, and $27.8 million and $27.5 million in the first nine months of 2014 and 2013, respectively. As of October 4, 2014, unrecognized compensation expense related to unvested RSUs was $33.9 million, which is expected to be recognized over a weighted-average period of 2.2 years.
		Restricted Stock Awards – Nucor’s Senior Officers Long-Term Incentive Plan (the “LTIP”) and Annual Incentive Plan (the “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 of the LTIP restricted stock award vests upon each of the first three anniversaries of the award date or, if earlier, upon the officer’s attainment of age 55 while employed by Nucor. Although participants are entitled to cash dividends and may vote such awarded shares, the sale or transfer of such shares is limited during the restricted period.
	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 of an annual incentive award. In such event, the deferred AIP award is converted into common stock units and credited with a deferral incentive, in the form of additional common stock units, equal to 25% of the number of common stock units attributable to the deferred AIP award. Common stock units attributable to deferred AIP awards are fully vested. Common stock units credited as a deferral incentive vest upon the AIP participant’s attainment of age 55 while employed by Nucor. Vested common stock units are paid to AIP participants in the form of shares of common stock following their termination of employment with Nucor.
	A summary of Nucor’s restricted stock activity under the AIP and LTIP for the first nine months of 2014 is as follows (shares in thousands):
			Shares			Grant Date
						Fair Value
	Restricted stock awards and units:
	Unvested at beginning of year			73		$	45.49
	Granted			127		$	50.35
	Vested			(135	)	$	48.76
	Canceled			—			—
	Unvested at October 4, 2014			65		$	48.2
	Shares reserved for future grants			1,111
	Compensation expense for common stock and common stock units awarded under the AIP and 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 $1.8 million and $1.2 million in the third quarter of 2014 and 2013, respectively, and $4.9 million and $4.5 million in the first nine months of 2014 and 2013, respectively. At October 4, 2014, unrecognized compensation expense related to unvested restricted stock awards was $1.0 million, which is expected to be recognized over a weighted-average period of 1.8 years.

EMPLOYEE_BENEFIT_PLAN

EMPLOYEE BENEFIT PLAN	9 Months Ended
	Oct. 04, 2014
Employee Benefit Plan [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 was $37.3 million and $22.5 million in the third quarter of 2014 and 2013, respectively, and was $77.5 million and $49.2 million in the first nine months of 2014 and 2013, respectively. The related liability for these benefits is included in salaries, wages and related accruals.

INTEREST_EXPENSE_INCOME

INTEREST EXPENSE (INCOME)	9 Months Ended
	Oct. 04, 2014
Interest Revenue (Expense), Net [Abstract]	'
INTEREST EXPENSE (INCOME)	'
	14	INTEREST EXPENSE (INCOME): The components of net interest expense are as follows (in thousands):
			Three Months (13 Weeks) Ended						Nine Months (39 Weeks) Ended
			Oct. 4, 2014			Sept. 28, 2013			Oct. 4, 2014			Sept. 28, 2013
	Interest expense		$	46,624		$	38,621		$	134,395		$	112,978
	Interest income			(1,275	)		(1,154	)		(3,914	)		(3,792	)
	Interest expense, net		$	45,349		$	37,467		$	130,481		$	109,186

INCOME_TAXES

INCOME TAXES	9 Months Ended
	Oct. 04, 2014
Income Tax Disclosure [Abstract]	'
INCOME TAXES	'
	15	INCOME TAXES: The effective tax rate for the third quarter of 2014 was 32.1% compared to 28.2% for the third quarter of 2013. The change in the effective tax rate for the third quarter of 2014 as compared to the third quarter of 2013 is primarily due to the change in relative proportions of net earnings attributable to noncontrolling interests to total pre-tax earnings between the periods and the adjustment of tax expense to previously filed returns. The Internal Revenue Service (“IRS”) is currently examining Nucor’s 2012 federal income tax return. Management believes that the Company has adequately provided for any adjustments that may arise from this audit. Nucor has concluded U.S. federal income tax matters for years through 2010. The 2011 and 2013 tax years are also open to examination by the IRS. Nucor has been informed by the Canada Revenue Authority of its intention to audit the Company’s 2012 Canadian returns. The tax years 2009 through 2013 remain open to examination by other major taxing jurisdictions to which Nucor is subject (primarily Canada and other state and local jurisdictions).
	Current deferred tax assets included in other current assets were $259.9 million at October 4, 2014 ($255.5 million at December 31, 2013). Current deferred tax liabilities included in accrued expenses and other current liabilities were $13.4 million at October 4, 2014 ($14.6 million at December 31, 2013). Non-current deferred tax liabilities included in deferred credits and other liabilities were $661.9 million at October 4, 2014 ($676.2 million at December 31, 2013).

STOCKHOLDERS_EQUITY

STOCKHOLDERS' EQUITY	9 Months Ended
	Oct. 04, 2014
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			Total
			Nucor Corporation			Noncontrolling Interests
	Stockholders’ equity at December 31, 2013		$	7,645,769		$	264,509		$	7,910,278
	Total comprehensive income			409,098			67,313			476,411
	Stock options			12,132			—			12,132
	Issuance of stock under award plans, net of forfeitures			24,242			—			24,242
	Amortization of unearned compensation			500			—			500
	Dividends declared			(356,459	)		—			(356,459	)
	Distributions to noncontrolling interests			—			(51,401	)		(51,401	)
	Stockholders’ equity at October 4, 2014		$	7,735,282		$	280,421		$	8,015,703
			Attributable to			Attributable to			Total
			Nucor Corporation			Noncontrolling Interests
	Stockholders’ equity at December 31, 2012		$	7,641,571		$	243,803		$	7,885,374
	Total comprehensive income			283,315			77,582			360,897
	Stock options			8,575			—			8,575
	Issuance of stock under award plans, net of forfeitures			24,568			—			24,568
	Amortization of unearned compensation			601			—			601
	Dividends declared			(353,424	)		—			(353,424	)
	Distributions to noncontrolling interests			—			(63,318	)		(63,318	)
	Stockholders’ equity at September 28, 2013		$	7,605,206		$	258,067		$	7,863,273

ACCUMULATED_OTHER_COMPREHENSIV

ACCUMULATED OTHER COMPREHENSIVE (LOSS) INCOME	9 Months Ended
	Oct. 04, 2014
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]	'
ACCUMULATED OTHER COMPREHENSIVE (LOSS) INCOME	'
	17	ACCUMULATED OTHER COMPREHENSIVE (LOSS) INCOME: The following tables reflect the changes in accumulated other comprehensive (loss) income by component (in thousands):
			Three Month (13 week) Period Ended
			October 4, 2014
			Gains and Losses on			Foreign Currency			Adjustment to Early		Total
			Hedging Derivatives			Gain (Loss)			Retiree Medical Plan
	July 5, 2014		$	(1,400	)	$	(19,070	)	$	16,518	$	(3,952	)
	Other comprehensive (loss) income before reclassifications			103			(81,689	)		—		(81,586	)
	Amounts reclassified from accumulated other comprehensive (loss) income into earnings			197			—			—		197
	Net current-period other comprehensive (loss) income			300			(81,689	)		—		(81,389	)
	October 4, 2014		$	(1,100	)	$	(100,759	)	$	16,518	$	(85,341	)
			Nine Month (39 week) Period Ended
			October 4, 2014
			Gains and Losses on			Foreign Currency			Adjustment to Early		Total
			Hedging Derivatives			Gain (Loss)			Retiree Medical Plan
	December 31, 2013		$	—		$	(7,438	)	$	16,518	$	9,080
	Other comprehensive (loss) income before reclassifications			(1,530	)		(93,321	)		—		(94,851	)
	Amounts reclassified from accumulated other comprehensive (loss) income into earnings			430			—			—		430
	Net current-period other comprehensive (loss) income			(1,100	)		(93,321	)		—		(94,421	)
	October 4, 2014		$	(1,100	)	$	(100,759	)	$	16,518	$	(85,341	)
			Three Month (13 week) Period Ended
			September 28, 2013
			Gains and Losses on			Foreign Currency			Adjustment to Early		Total
			Hedging Derivatives			Gain (Loss)			Retiree Medical Plan
	June 29, 2013		$	—		$	(19,914	)	$	10,580	$	(9,334	)
	Other comprehensive (loss) income before reclassifications			—			31,879			—		31,879
	Amounts reclassified from accumulated other comprehensive (loss) income into earnings			—			—			—		—
	Net current-period other comprehensive (loss) income			—			31,879			—		31,879
	September 28, 2013		$	—		$	11,965		$	10,580	$	22,545
			Nine Month (39 week) Period Ended
			September 28, 2013
			Gains and Losses on			Foreign Currency			Adjustment to Early		Total
			Hedging Derivatives			Gain (Loss)			Retiree Medical Plan
	December 31, 2012		$	—		$	46,181		$	10,580	$	56,761
	Other comprehensive (loss) income before reclassifications			—			(34,216	)		—		(34,216	)
	Amounts reclassified from accumulated other comprehensive (loss) income into earnings			—			—			—		—
	Net current-period other comprehensive (loss) income			—			(34,216	)		—		(34,216	)
	September 28, 2013		$	—		$	11,965		$	10,580	$	22,545

SEGMENTS

SEGMENTS	9 Months Ended
	Oct. 04, 2014
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; 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 expanded metal, and wire and wire mesh. The raw materials segment includes DJJ, a scrap broker and processor; Nu-Iron Unlimited and Nucor Steel Louisiana, two facilities that produce direct reduced iron used by the steel mills; our natural gas working interests; and Nucor’s equity method investment in Hunter Ridge. The steel mills, steel products and raw materials segments are consistent with the way Nucor manages its business, which is primarily based upon the similarity of the types of products produced and sold by each segment.
	Net interest expense, other income, profit sharing expense, stock-based compensation and changes in the LIFO reserve are shown under Corporate/eliminations. Corporate assets primarily include cash and cash equivalents, short-term investments, allowances to eliminate intercompany profit in inventory, fair value of natural gas hedges, deferred income tax assets, federal and state income taxes receivable, the LIFO reserve and investments in and advances to affiliates.
	Nucor’s results by segment were as follows (in thousands):
			Three Months (13 Weeks) Ended						Nine Months (39 Weeks) Ended
			Oct. 4, 2014			Sept. 28, 2013			Oct. 4, 2014			Sept. 28, 2013
	Net sales to external customers:
	Steel mills		$	3,898,031		$	3,435,884		$	11,179,935		$	9,901,471
	Steel products			1,142,043			964,153			3,052,135			2,690,604
	Raw materials			661,795			540,899			1,869,318			1,565,221
			$	5,701,869		$	4,940,936		$	16,101,388		$	14,157,296
	Intercompany sales:
	Steel mills		$	797,396		$	652,077		$	2,248,462		$	1,924,222
	Steel products			34,215			24,909			82,257			75,036
	Raw materials			2,492,453			2,391,502			7,463,951			6,738,485
	Corporate/eliminations			(3,324,064	)		(3,068,488	)		(9,794,670	)		(8,737,743	)
			$	—		$	—		$	—		$	—
	Earnings (loss) before income taxes and noncontrolling interests:
	Steel mills		$	502,703		$	310,591		$	1,188,638		$	819,951
	Steel products			63,890			31,018			108,222			51,167
	Raw materials			(19,321	)		(493	)		(20,597	)		13,261
	Corporate/eliminations			(143,287	)		(92,914	)		(422,912	)		(330,517	)
			$	403,985		$	248,202		$	853,351		$	553,862
			Oct. 4, 2014			Dec. 31, 2013
	Segment assets:
	Steel mills		$	8,489,079		$	8,365,023
	Steel products			3,028,321			2,861,403
	Raw materials			4,026,534			3,956,913
	Corporate/eliminations			(50,340	)		19,944
			$	15,493,594		$	15,203,283

EARNINGS_PER_SHARE

EARNINGS PER SHARE	9 Months Ended
	Oct. 04, 2014
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						Nine Months (39 Weeks) Ended
			Oct. 4, 2014			Sept. 28, 2013			Oct. 4, 2014			Sept. 28, 2013
	Basic net earnings per share:
	Basic net earnings		$	245,447		$	147,597		$	503,519		$	317,531
	Earnings allocated to participating securities			(781	)		(518	)		(1,659	)		(1,324	)
	Net earnings available to common stockholders		$	244,666		$	147,079		$	501,860		$	316,207
	Average shares outstanding			320,023			319,341			319,737			318,979
	Basic net earnings per share		$	0.76		$	0.46		$	1.57		$	0.99
	Diluted net earnings per share:
	Diluted net earnings		$	245,447		$	147,597		$	503,519		$	317,531
	Earnings allocated to participating securities			(781	)		(518	)		(1,659	)		(1,324	)
	Net earnings available to common stockholders		$	244,666		$	147,079		$	501,860		$	316,207
	Diluted average shares outstanding:
	Basic shares outstanding			320,023			319,341			319,737			318,979
	Dilutive effect of stock options and other			314			185			288			153
				320,337			319,526			320,025			319,132
	Diluted net earnings per share		$	0.76		$	0.46		$	1.57		$	0.99
	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						Nine Months (39 Weeks) Ended
			Oct. 4, 2014			Sept. 28, 2013			Oct. 4, 2014			Sept. 28, 2013
	Anti-dilutive stock options:
	Weighted average shares			—			—			—			183
	Weighted average exercise price		$	—		$	—		$	—		$	44.51

SUBSEQUENT_EVENTS

SUBSEQUENT EVENTS	9 Months Ended
	Oct. 04, 2014
Subsequent Events [Abstract]	'
SUBSEQUENT EVENTS	'
	20	SUBSEQUENT EVENTS: On October 8, 2014, Nucor acquired the entire equity interest in Gallatin Steel Company for a cash purchase price of approximately $775.1 million, including our most recent estimate of working capital adjustments. The acquisition was partially funded by the issuance of approximately $300 million of commercial paper subsequent to the end of the third quarter, with the remaining funds coming from cash on hand. Located on the Ohio River in Ghent, Kentucky, Gallatin has an annual sheet steel production capacity of approximately 1,800,000 tons. This acquisition is strategically important as it expands Nucor’s footprint in the Midwestern United States market, and it will broaden Nucor’s product offerings in the growing steel pipe and tube segment.
	On November 2, 2014, a major equipment failure occurred at Nucor Steel Louisiana in St. James Parish related to the process gas heater. There were no injuries, no environmental impact and no damage to any other part of the direct reduced iron facility as a result of this incident. Production operations were suspended after the failure. Nucor is still assessing the extent of the equipment damage and cannot currently estimate the length of time needed to make the necessary repairs to the process gas heater. Additionally, Nucor is not able to estimate the extent of any possible write down to the carrying value of the affected equipment at this time.

GOODWILL_AND_OTHER_INTANGIBLE_1

GOODWILL AND OTHER INTANGIBLE ASSETS (Tables)	9 Months Ended
	Oct. 04, 2014
Goodwill and Intangible Assets Disclosure [Abstract]	'
Schedule of Change in Net Carrying Amount of Goodwill by Segment	'
		The change in the net carrying amount of goodwill for the nine months ended October 4, 2014 by segment is as follows (in thousands):
			Steel Mills		Steel Products			Raw Materials		Total
	Balance at December 31, 2013		$	495,897	$	774,486		$	703,225	$	1,973,608
	Other			—		311			26,352		26,663
	Translation			—		(17,495	)		—		(17,495	)
	Balance at October 4, 2014		$	495,897	$	757,302		$	729,577	$	1,982,776
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 were comprised of the following (in thousands):
			Oct. 4, 2014					Dec. 31, 2013
			Gross		Accumulated			Gross		Accumulated
			Amount		Amortization			Amount		Amortization
	Customer relationships		$	1,146,859	$	438,649		$	1,147,786	$	391,254
	Trademarks and trade names			150,355		46,100			151,332		40,397
	Other			22,823		16,210			21,869		15,182
			$	1,320,037	$	500,959		$	1,320,987	$	446,833

DERIVATIVES_Tables

DERIVATIVES (Tables)	9 Months Ended
	Oct. 04, 2014
Fair Values 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	Oct. 4,			Dec. 31,
			2014			2013
	Asset derivatives not designated as hedging instruments:
	Commodity contracts	Other current assets	$	1,384		$	—
	Foreign exchange contracts	Other current assets		57			—
	Total asset derivatives		$	1,441		$	—
	Liability derivatives designated as hedging instruments:
	Commodity contracts	Accrued expenses and other current liabilities		(1,700	)		—
	Commodity contracts	Deferred credits and other liabilities		(100	)		—
	Total Liability derivatives designated as hedging instruments			(1,800	)		—
	Liability derivatives not designated as hedging instruments:
	Commodity contracts	Accrued expenses and other current liabilities		—			(553	)
	Foreign exchange contracts	Accrued expenses and other current liabilities		—			(2	)
	Total liability derivatives not designated as hedging instruments			—			(555	)
	Total liability derivatives		$	(1,800	)	$	(555	)
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
	Derivatives in Cash Flow Hedging	Statement of	Amount of Gain						Amount of Gain					Amount of Gain
	Relationships	Earnings Location	or (Loss),						or (Loss),					or (Loss),
			net of tax,						net of tax,					net of tax,
			Recognized in OCI						Reclassified from					Recognized in
			on Derivatives						Accumulated OCI  into					Earnings on
			(Effective Portion)						Earnings					Derivatives
									(Effective Portion)					(Ineffective Portion)
			Three Months						Three Months					Three Months
			(13 weeks) Ended						(13 weeks) Ended					(13 weeks) Ended
			Oct. 4, 2014			Sept. 28, 2013			Oct. 4, 2014			Sept. 28, 2013		Oct. 4, 2014		Sept. 28, 2013
	Commodity contracts	Cost of products sold	$	103		$	—		$	(197	)	$	—	$	—	$	—
	Derivatives in Cash Flow Hedging	Statement of	Amount of Gain						Amount of Gain					Amount of Gain
	Relationships	Earnings Location	or (Loss),						or (Loss),					or (Loss),
			net of tax,						net of tax,					net of tax,
			Recognized in OCI						Reclassified from					Recognized in
			on Derivatives						Accumulated OCI  into					Earnings on
			(Effective Portion)						Earnings					Derivatives
									(Effective Portion)					(Ineffective Portion)
			Nine Months						Nine Months					Nine Months
			(39 weeks) Ended						(39 weeks) Ended					(39 weeks) Ended
			Oct. 4, 2014			Sept. 28, 2013			Oct. 4, 2014			Sept. 28, 2013		Oct. 4, 2014		Sept. 28, 2013
	Commodity contracts	Cost of products sold	$	(1,530	)	$	—		$	(430	)	$	—	$	—	$	—
Derivatives Not Designated as Hedging Instrument [Member]	'
Effect of Derivative Instruments on Condensed Consolidated Statements of Earnings	'
	Derivatives Not Designated as Hedging Instruments
	Derivatives Not Designated as	Statement of	Amount of Gain or (Loss) Recognized in Earnings on Derivatives
	Hedging Instruments	Earnings Location	Three Months (13 weeks) Ended						Nine Months (39 weeks) Ended
			Oct. 4,			Sept. 28,			Oct. 4,			Sept. 28,
			2014			2013			2014			2013
	Commodity contracts	Cost of products sold	$	844		$	(789	)	$	1,282		$	4,193
	Foreign exchange contracts	Cost of products sold		314			134			266			253
	Total		$	1,158		$	(655	)	$	1,548		$	4,446

FAIR_VALUE_MEASUREMENTS_Tables

FAIR VALUE MEASUREMENTS (Tables)	9 Months Ended
	Oct. 04, 2014
Fair Value Disclosures [Abstract]	'
Schedule of Financial Assets and Financial Liabilities Measured at Fair Value	'
		The following table summarizes information regarding Nucor’s financial assets and financial liabilities that were measured at fair value as of October 4, 2014 and December 31, 2013 (in thousands). Nucor does not currently have any non-financial assets or liabilities that are measured at fair value on a recurring basis.
						Fair Value Measurements at Reporting Date Using
	Description		Carrying			Quoted Prices		Significant			Significant
			Amount in			in Active		Other			Unobservable
			Condensed			Markets for		Observable			Inputs
			Consolidated			Identical		Inputs			(Level 3)
			Balance Sheets			Assets		(Level 2)
						(Level 1)
	As of October 4, 2014
	Assets:
	Cash equivalents		$	1,140,092		$	1,140,092	$	—		$	—
	Short-term investments			100,000			100,000		—			—
	Foreign exchange and commodity contracts			1,441			—		1,441			—
	Total assets		$	1,241,533		$	1,240,092	$	1,441		$	—
	Liabilities:
	Commodity contracts		$	(1,800	)	$	—	$	(1,800	)	$	—
	As of December 31, 2013
	Assets:
	Cash equivalents		$	1,269,465		$	1,269,465	$	—		$	—
	Short-term investments			28,191			28,191		—			—
	Total assets		$	1,297,656		$	1,297,656	$	—		$	—
	Liabilities:
	Foreign exchange and commodity contracts		$	(555	)	$	—	$	(555	)	$	—

STOCKBASED_COMPENSATION_Tables

STOCK-BASED COMPENSATION (Tables)	9 Months Ended
	Oct. 04, 2014
Summary of Stock Option Plans Activity	'
	A summary of activity under Nucor’s stock option plans for the first nine months of 2014 is as follows (in thousands, except year and per share amounts):
		Shares			Weighted -		Weighted -		Aggregate
					Average		Average		Intrinsic
					Exercise		Remaining		Value
					Price		Contractual Life
	Number of shares under option:
	Outstanding at beginning of year		2,089		$	40.47
	Granted		469		$	50.63
	Exercised		(112	)	$	40.01			$	1,891
	Canceled		—			—
	Outstanding at October 4, 2014		2,446		$	42.43		7.7 years	$	23,349
	Options exercisable at October 4, 2014		1,287		$	40.53		6.7 years	$	14,744
Summary of Nucor's Restricted Stock Unit Activity	'
	A summary of Nucor’s RSU activity for the first nine months of 2014 is as follows (shares in thousands):
		Shares			Grant Date
					Fair Value
	Restricted stock units:
	Unvested at beginning of year		1,122		$	42.51
	Granted		655		$	50.63
	Vested		(749	)	$	44.9
	Canceled		(13	)	$	42.66
	Unvested at October 4, 2014		1,015		$	45.98
	Shares reserved for future grants (stock options and RSUs)		11,860
AIP and LTIP [Member]	'
Summary of Nucor's Restricted Stock Activity under AIP and LTIP	'
	A summary of Nucor’s restricted stock activity under the AIP and LTIP for the first nine months of 2014 is as follows (shares in thousands):
		Shares			Grant Date
					Fair Value
	Restricted stock awards and units:
	Unvested at beginning of year		73		$	45.49
	Granted		127		$	50.35
	Vested		(135	)	$	48.76
	Canceled		—			—
	Unvested at October 4, 2014		65		$	48.2
	Shares reserved for future grants		1,111

INTEREST_EXPENSE_INCOME_Tables

INTEREST EXPENSE (INCOME) (Tables)	9 Months Ended
	Oct. 04, 2014
Interest Revenue (Expense), Net [Abstract]	'
Schedule of Components of Interest Expense, Net	'
		The components of net interest expense are as follows (in thousands):
			Three Months (13 Weeks) Ended						Nine Months (39 Weeks) Ended
			Oct. 4, 2014			Sept. 28, 2013			Oct. 4, 2014			Sept. 28, 2013
	Interest expense		$	46,624		$	38,621		$	134,395		$	112,978
	Interest income			(1,275	)		(1,154	)		(3,914	)		(3,792	)
	Interest expense, net		$	45,349		$	37,467		$	130,481		$	109,186

STOCKHOLDERS_EQUITY_Tables

STOCKHOLDERS' EQUITY (Tables)	9 Months Ended
	Oct. 04, 2014
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			Total
			Nucor Corporation			Noncontrolling Interests
	Stockholders’ equity at December 31, 2013		$	7,645,769		$	264,509		$	7,910,278
	Total comprehensive income			409,098			67,313			476,411
	Stock options			12,132			—			12,132
	Issuance of stock under award plans, net of forfeitures			24,242			—			24,242
	Amortization of unearned compensation			500			—			500
	Dividends declared			(356,459	)		—			(356,459	)
	Distributions to noncontrolling interests			—			(51,401	)		(51,401	)
	Stockholders’ equity at October 4, 2014		$	7,735,282		$	280,421		$	8,015,703
			Attributable to			Attributable to			Total
			Nucor Corporation			Noncontrolling Interests
	Stockholders’ equity at December 31, 2012		$	7,641,571		$	243,803		$	7,885,374
	Total comprehensive income			283,315			77,582			360,897
	Stock options			8,575			—			8,575
	Issuance of stock under award plans, net of forfeitures			24,568			—			24,568
	Amortization of unearned compensation			601			—			601
	Dividends declared			(353,424	)		—			(353,424	)
	Distributions to noncontrolling interests			—			(63,318	)		(63,318	)
	Stockholders’ equity at September 28, 2013		$	7,605,206		$	258,067		$	7,863,273

ACCUMULATED_OTHER_COMPREHENSIV1

ACCUMULATED OTHER COMPREHENSIVE (LOSS) INCOME (Tables)	9 Months Ended
	Oct. 04, 2014
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]	'
Components of Accumulated Other Comprehensive (Loss) Income	'
	The following tables reflect the changes in accumulated other comprehensive (loss) income by component (in thousands):
		Three Month (13 week) Period Ended
		October 4, 2014
		Gains and Losses on			Foreign Currency			Adjustment to Early		Total
		Hedging Derivatives			Gain (Loss)			Retiree Medical Plan
	July 5, 2014	$	(1,400	)	$	(19,070	)	$	16,518	$	(3,952	)
	Other comprehensive (loss) income before reclassifications		103			(81,689	)		—		(81,586	)
	Amounts reclassified from accumulated other comprehensive (loss) income into earnings		197			—			—		197
	Net current-period other comprehensive (loss) income		300			(81,689	)		—		(81,389	)
	October 4, 2014	$	(1,100	)	$	(100,759	)	$	16,518	$	(85,341	)
		Nine Month (39 week) Period Ended
		October 4, 2014
		Gains and Losses on			Foreign Currency			Adjustment to Early		Total
		Hedging Derivatives			Gain (Loss)			Retiree Medical Plan
	December 31, 2013	$	—		$	(7,438	)	$	16,518	$	9,080
	Other comprehensive (loss) income before reclassifications		(1,530	)		(93,321	)		—		(94,851	)
	Amounts reclassified from accumulated other comprehensive (loss) income into earnings		430			—			—		430
	Net current-period other comprehensive (loss) income		(1,100	)		(93,321	)		—		(94,421	)
	October 4, 2014	$	(1,100	)	$	(100,759	)	$	16,518	$	(85,341	)
		Three Month (13 week) Period Ended
		September 28, 2013
		Gains and Losses on			Foreign Currency			Adjustment to Early		Total
		Hedging Derivatives			Gain (Loss)			Retiree Medical Plan
	June 29, 2013	$	—		$	(19,914	)	$	10,580	$	(9,334	)
	Other comprehensive (loss) income before reclassifications		—			31,879			—		31,879
	Amounts reclassified from accumulated other comprehensive (loss) income into earnings		—			—			—		—
	Net current-period other comprehensive (loss) income		—			31,879			—		31,879
	September 28, 2013	$	—		$	11,965		$	10,580	$	22,545
		Nine Month (39 week) Period Ended
		September 28, 2013
		Gains and Losses on			Foreign Currency			Adjustment to Early		Total
		Hedging Derivatives			Gain (Loss)			Retiree Medical Plan
	December 31, 2012	$	—		$	46,181		$	10,580	$	56,761
	Other comprehensive (loss) income before reclassifications		—			(34,216	)		—		(34,216	)
	Amounts reclassified from accumulated other comprehensive (loss) income into earnings		—			—			—		—
	Net current-period other comprehensive (loss) income		—			(34,216	)		—		(34,216	)
	September 28, 2013	$	—		$	11,965		$	10,580	$	22,545

SEGMENTS_Tables

SEGMENTS (Tables)	9 Months Ended
	Oct. 04, 2014
Segment Reporting [Abstract]	'
Segments	'
	Nucor’s results by segment were as follows (in thousands):
		Three Months (13 Weeks) Ended						Nine Months (39 Weeks) Ended
		Oct. 4, 2014			Sept. 28, 2013			Oct. 4, 2014			Sept. 28, 2013
	Net sales to external customers:
	Steel mills	$	3,898,031		$	3,435,884		$	11,179,935		$	9,901,471
	Steel products		1,142,043			964,153			3,052,135			2,690,604
	Raw materials		661,795			540,899			1,869,318			1,565,221
		$	5,701,869		$	4,940,936		$	16,101,388		$	14,157,296
	Intercompany sales:
	Steel mills	$	797,396		$	652,077		$	2,248,462		$	1,924,222
	Steel products		34,215			24,909			82,257			75,036
	Raw materials		2,492,453			2,391,502			7,463,951			6,738,485
	Corporate/eliminations		(3,324,064	)		(3,068,488	)		(9,794,670	)		(8,737,743	)
		$	—		$	—		$	—		$	—
	Earnings (loss) before income taxes and noncontrolling interests:
	Steel mills	$	502,703		$	310,591		$	1,188,638		$	819,951
	Steel products		63,890			31,018			108,222			51,167
	Raw materials		(19,321	)		(493	)		(20,597	)		13,261
	Corporate/eliminations		(143,287	)		(92,914	)		(422,912	)		(330,517	)
		$	403,985		$	248,202		$	853,351		$	553,862
		Oct. 4, 2014			Dec. 31, 2013
	Segment assets:
	Steel mills	$	8,489,079		$	8,365,023
	Steel products		3,028,321			2,861,403
	Raw materials		4,026,534			3,956,913
	Corporate/eliminations		(50,340	)		19,944
		$	15,493,594		$	15,203,283

EARNINGS_PER_SHARE_Tables

EARNINGS PER SHARE (Tables)	9 Months Ended
	Oct. 04, 2014
Earnings Per Share [Abstract]	'
Computations of Basic and Diluted Net Earnings Per Share	'
	18	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						Nine Months (39 Weeks) Ended
			Oct. 4, 2014			Sept. 28, 2013			Oct. 4, 2014			Sept. 28, 2013
	Basic net earnings per share:
	Basic net earnings		$	245,447		$	147,597		$	503,519		$	317,531
	Earnings allocated to participating securities			(781	)		(518	)		(1,659	)		(1,324	)
	Net earnings available to common stockholders		$	244,666		$	147,079		$	501,860		$	316,207
	Average shares outstanding			320,023			319,341			319,737			318,979
	Basic net earnings per share		$	0.76		$	0.46		$	1.57		$	0.99
	Diluted net earnings per share:
	Diluted net earnings		$	245,447		$	147,597		$	503,519		$	317,531
	Earnings allocated to participating securities			(781	)		(518	)		(1,659	)		(1,324	)
	Net earnings available to common stockholders		$	244,666		$	147,079		$	501,860		$	316,207
	Diluted average shares outstanding:
	Basic shares outstanding			320,023			319,341			319,737			318,979
	Dilutive effect of stock options and other			314			185			288			153
				320,337			319,526			320,025			319,132
	Diluted net earnings per share		$	0.76		$	0.46		$	1.57		$	0.99
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						Nine Months (39 Weeks) Ended
			Oct. 4, 2014			Sept. 28, 2013			Oct. 4, 2014			Sept. 28, 2013
	Anti-dilutive stock options:
	Weighted average shares			—			—			—			183
	Weighted average exercise price		$	—		$	—		$	—		$	44.51

Accounts_Receivable_Additional

Accounts Receivable - Additional Information (Detail) (USD $)	Oct. 04, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Accounts Receivable, Net [Abstract]	'	'
Allowance for doubtful accounts receivable	$62.10	$58.30

Inventories_Additional_Informa

Inventories - Additional Information (Detail) (USD $)	Oct. 04, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Inventory Disclosure [Abstract]	'	'
Raw materials and supplies in inventory, percentage	40.00%	40.00%
Finished and semi-finished products in inventory, percentage	60.00%	60.00%
Inventories valued using the last-in, first-out	46.00%	45.00%
Increased value of inventory if FIFO method had been used	$624.70	$624.70
Lower of cost or market adjustments	$2.60	$2.10

Property_Plant_and_Equipment_A

Property, Plant and Equipment - Additional information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Oct. 04, 2014
Property, Plant and Equipment [Line Items]	'	'
Accumulated depreciation	$6,630,000,000	$7,070,000,000
Property, plant and equipment net of accumulated depreciation, under a capital lease agreement	0	23,500,000
Gross property, plant and equipment acquired under capital lease	'	25,400,000
Total obligations associated with capital lease agreement	0	23,700,000
Capital lease obligations classified in accrued expenses and other current liabilities	'	2,200,000
Capital lease obligations classified in deferred credits and other liabilities	'	21,500,000
Property plant and equipment written down	21,000,000	'
Inventory written down	7,000,000	'
Insurance receivable	14,000,000	'
Associated net charges included in marketing, administrative and other expenses	14,000,000	'
Property, plant and equipment, net	4,917,024,000	4,884,010,000
Two remaining storage domes [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Property, plant and equipment, net	'	$21,000,000

Recovered_Sheet1

Restricted Cash and Investments - Additional Information (Detail) (USD $)	9 Months Ended			0 Months Ended
	Sep. 28, 2013	Oct. 04, 2014	Dec. 31, 2013	Nov. 30, 2010
				30-Year Variable Rate Gulf Opportunity Zone Bonds [Member]
Restricted Cash and Investments [Line Items]	'	'	'	'
Debt instrument face amount	'	'	'	$600,000,000
Term of variable rate bonds, years	'	'	'	'30 years
Qualified expenditure for construction of facility	274,900,000	'	'	'
Restricted cash or investment	'	$0	$0	'

Recovered_Sheet2

Goodwill and Other Intangible Assets - Schedule of Change in Net Carrying Amount of Goodwill by Segment (Detail) (USD $)	3 Months Ended	9 Months Ended
In Thousands, unless otherwise specified	Oct. 04, 2014	Oct. 04, 2014
Goodwill [Line Items]	'	'
Balance, beginning of period	'	$1,973,608
Other	26,400	26,663
Translation	'	-17,495
Balance, end of period	1,982,776	1,982,776
Steel Mills [Member]	'	'
Goodwill [Line Items]	'	'
Balance, beginning of period	'	495,897
Other	'	0
Translation	'	0
Balance, end of period	495,897	495,897
Steel Products [Member]	'	'
Goodwill [Line Items]	'	'
Balance, beginning of period	'	774,486
Other	'	311
Translation	'	-17,495
Balance, end of period	757,302	757,302
Raw Materials [Member]	'	'
Goodwill [Line Items]	'	'
Balance, beginning of period	'	703,225
Other	'	26,352
Translation	'	0
Balance, end of period	$729,577	$729,577

Recovered_Sheet3

Goodwill and Other Intangible Assets - Additional Information (Detail) (USD $)	3 Months Ended			9 Months Ended
	Oct. 04, 2014	Dec. 31, 2013	Sep. 28, 2013	Oct. 04, 2014	Sep. 28, 2013
Finite And Indefinite Lived Intangible Assets [Line Items]	'	'	'	'	'
Increased goodwill due to correction of deferred tax	$26,400,000	'	'	$26,663,000	'
Impairment of goodwill	'	0	'	'	'
Intangible asset amortization expense	17,900,000	'	18,500,000	54,100,000	56,100,000
Future amortization expense, in 2014	71,400,000	'	'	71,400,000	'
Future amortization expense, in 2015	68,600,000	'	'	68,600,000	'
Future amortization expense, in 2016	66,900,000	'	'	66,900,000	'
Future amortization expense, in 2017	65,200,000	'	'	65,200,000	'
Future amortization expense, in 2018	$61,500,000	'	'	$61,500,000	'
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_Intangible_2

Goodwill and Other Intangible Assets - Schedule of Intangible Assets (Detail) (USD $)	Oct. 04, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Finite-Lived Intangible Assets [Line Items]	'	'
Intangible assets, Gross Amount	$1,320,037	$1,320,987
Intangible assets, Accumulated Amortization	500,959	446,833
Customer relationships [Member]	'	'
Finite-Lived Intangible Assets [Line Items]	'	'
Intangible assets, Gross Amount	1,146,859	1,147,786
Intangible assets, Accumulated Amortization	438,649	391,254
Trademarks and trade names [Member]	'	'
Finite-Lived Intangible Assets [Line Items]	'	'
Intangible assets, Gross Amount	150,355	151,332
Intangible assets, Accumulated Amortization	46,100	40,397
Other [Member]	'	'
Finite-Lived Intangible Assets [Line Items]	'	'
Intangible assets, Gross Amount	22,823	21,869
Intangible assets, Accumulated Amortization	$16,210	$15,182

Equity_Investments_Additional_

Equity Investments - Additional Information (Detail)

9 Months Ended

1 Months Ended

3 Months Ended

6 Months Ended

9 Months Ended

9 Months Ended

9 Months Ended

9 Months Ended

Oct. 04, 2014

Sep. 28, 2013

Dec. 31, 2013

Oct. 04, 2014

Dec. 31, 2013

Oct. 04, 2014

Sep. 28, 2013

Jun. 30, 2012

Oct. 04, 2014

Sep. 28, 2013

Oct. 04, 2014

Dec. 31, 2013

Dec. 31, 2013

Oct. 04, 2014

Oct. 04, 2014

Oct. 04, 2014

Oct. 04, 2014

Dec. 31, 2013

Dec. 31, 2013

Oct. 04, 2014

Dec. 31, 2013

Oct. 04, 2014

Oct. 04, 2014

Oct. 04, 2014

2-May-14

USD ($)

USD ($)

USD ($)

Hunter Ridge Energy Services LLC [Member]

Hunter Ridge Energy Services LLC [Member]

Duferdofin Nucor S.r.l. [Member]

Duferdofin Nucor S.r.l. [Member]

Duferdofin Nucor S.r.l. [Member]

Duferdofin Nucor S.r.l. [Member]

Duferdofin Nucor S.r.l. [Member]

Duferdofin Nucor S.r.l. [Member]

Duferdofin Nucor S.r.l. [Member]

Duferdofin Nucor S.r.l. [Member]

Duferdofin Nucor S.r.l. [Member]

Duferdofin Nucor S.r.l. [Member]

Duferdofin Nucor S.r.l. [Member]

Duferdofin Nucor S.r.l. [Member]

Duferdofin Nucor S.r.l. [Member]

Duferdofin Nucor S.r.l. [Member]

NuMit LLC [Member]

NuMit LLC [Member]

Steel Technologies LLC [Member]

Steel Technologies LLC [Member]

Steel Technologies LLC [Member]

Steel Technologies LLC [Member]

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

EUR (€)

USD ($)

EUR (€)

Standby Medium Long Term Credit Facility [Member]

Standby Medium Long Term Credit Facility [Member]

Facility A [Member]

Facility A [Member]

Facility A [Member]

Facility A [Member]

USD ($)

USD ($)

USD ($)

Notes Receivable One [Member]

Notes Receivable Two [Member]

Notes Receivable Two [Member]

USD ($)

EUR (€)

USD ($)

EUR (€)

USD ($)

EUR (€)

Sheet

USD ($)

USD ($)

Schedule of Equity Method Investments [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Equity method investment

$923,200,000

'

$936,000,000

$137,900,000

$134,500,000

$431,000,000

'

'

$431,000,000

'

'

$465,400,000

'

'

'

'

'

'

'

$334,900,000

$318,400,000

'

'

'

'

Period used for lag basis, in months

'

'

'

'1 month

'

'

'

'

'1 month

'

'

'

'

'

'

'

'

'

'

'1 month

'

'

'

'

'

Equity method investment, ownership percentage

'

'

'

50.00%

'

50.00%

'

'

50.00%

'

'

'

'

'

'

'

'

'

'

50.00%

'

'

'

'

'

Equity method investments, share of net assets

'

'

'

'

'

58,900,000

'

'

58,900,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Basis difference due to the step-up to fair value of certain assets and liabilities

'

'

'

'

'

372,100,000

'

'

372,100,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Step-up to fair value of equity method investment, portion related to identification of goodwill

'

'

'

'

'

'

'

'

302,200,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Amortization expense and other purchase accounting adjustments due to fair value step-up

54,127,000

56,051,000

'

'

'

2,600,000

2,800,000

'

8,000,000

8,500,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Due from related parties, noncurrent

'

'

'

'

'

43,800,000

'

'

43,800,000

'

35,000,000

48,200,000

35,000,000

'

'

'

'

'

'

'

'

'

'

'

'

Notes receivable, related parties, interest rate

'

'

'

'

'

'

'

'

1.34%

'

'

'

'

'

'

'

'

'

'

'

'

'

1.13%

1.44%

'

Interest rate per year in excess of Euribor as of date of the notes

'

'

'

'

'

'

'

'

1.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Equity method investments note payable with parent company, maturity date

'

'

'

'

'

'

'

'

31-Jan-16

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1-May-15

'

Equity method investments credit facilities, amount

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

122,500,000

'

'

'

'

'

'

'

'

Total amount outstanding under equity method investments credit facilities

'

'

'

'

'

'

'

'

'

'

'

'

'

75,100,000

60,000,000

131,400,000

105,000,000

154,400,000

112,000,000

'

'

'

'

'

'

Line of credit facility, maturity period

'

'

'

'

'

'

'

'

'

'

'

'

'

22-Apr-16

22-Apr-16

26-Apr-16

26-Apr-16

'

'

'

'

1-Apr-15

'

'

'

Guarantor obligation percentage of exposure in case of default

'

'

'

'

'

'

'

'

'

'

'

'

'

50.00%

50.00%

50.00%

50.00%

'

'

'

'

'

'

'

'

Equity method investment, ownership percentage

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

100.00%

'

'

'

Number of sheet processing facilities operated by Steel Technologies

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

25

'

'

'

Notes receivable, related parties

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

40,000,000

'

44,000,000

Basis points in excess of LIBOR on note receivable from related party

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

0.90%

'

'

Line of credit extended to joint venture

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

60,000,000

'

'

'

Line of credit extended to joint venture, amount outstanding

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

8,500,000

'

'

'

Line of credit extended to joint venture, interest rate

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1.34%

'

'

'

Impairment of equity method investments

'

'

'

'

'

'

'

$30,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Current_Liabilities_Additional

Current Liabilities - Additional Information (Detail) (USD $)	Oct. 04, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Liabilities, Current [Abstract]	'	'
Book overdrafts	$118.20	$81.60
Dividends payable, current	$118.90	$118.70

Derivatives_Additional_Informa

Derivatives - Additional Information (Detail)	Oct. 04, 2014
	MMBTU
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'
Notional amount of commodity derivatives	16,000,000

Derivatives_Fair_Values_of_Der

Derivatives - Fair Values of Derivative Instruments (Detail) (USD $)	Oct. 04, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Derivatives, Fair Value [Line Items]	'	'
Derivative Liabilities, Fair Value	($1,800)	($555)
Derivatives Designated as Hedging Instrument [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Derivative Liabilities, Fair Value	-1,800	0
Derivatives Not Designated as Hedging Instrument [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Derivative Assets, Fair Value	1,441	0
Derivative Liabilities, Fair Value	0	-555
Commodity contracts [Member] | Derivatives Designated as Hedging Instrument [Member] | Accrued Expenses and Other Current Liabilities [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Derivative Liabilities, Fair Value	-1,700	0
Commodity contracts [Member] | Derivatives Designated as Hedging Instrument [Member] | Deferred Credits and Other Liabilities [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Derivative Liabilities, Fair Value	-100	0
Commodity contracts [Member] | Derivatives Not Designated as Hedging Instrument [Member] | Other current assets [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Derivative Assets, Fair Value	1,384	0
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	0	-553
Foreign exchange contracts [Member] | Derivatives Not Designated as Hedging Instrument [Member] | Other current assets [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Derivative Assets, Fair Value	57	0
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	$0	($2)

Derivatives_Effect_of_Derivati

Derivatives - Effect of Derivative Instruments on Condensed Consolidated Statements of Earnings (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Oct. 04, 2014	Sep. 28, 2013	Oct. 04, 2014	Sep. 28, 2013
Derivatives Not Designated as Hedging Instrument [Member]	'	'	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'	'	'
Amount of Gain or (Loss) Recognized in Earnings on Derivatives	$1,158	($655)	$1,548	$4,446
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	844	-789	1,282	4,193
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)	103	0	-1,530	0
Amount of Gain or (Loss), net of tax, Reclassified from Accumulated OCI into Earnings (Effective Portion)	-197	0	-430	0
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	$314	$134	$266	$253

Fair_Value_Measurements_Schedu

Fair Value Measurements - Schedule of Financial Assets and Financial Liabilities Measured at Fair Value (Detail) (USD $)	Oct. 04, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Short-term investments	$100,000	$28,191
Total assets	15,493,594	15,203,283
Commodity contracts	-1,800	-555
Reported Value Measurement [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Cash equivalents	1,140,092	1,269,465
Short-term investments	100,000	28,191
Foreign exchange and commodity contracts	1,441	'
Total assets	1,241,533	1,297,656
Commodity contracts	-1,800	-555
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	1,140,092	1,269,465
Short-term investments	100,000	28,191
Total assets	1,240,092	1,297,656
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Foreign exchange and commodity contracts	1,441	'
Total assets	1,441	'
Commodity contracts	($1,800)	($555)

Fair_Value_Measurements_Additi

Fair Value Measurements - Additional Information (Detail) (USD $)	Oct. 04, 2014	Dec. 31, 2013
In Billions, unless otherwise specified
Fair Value Disclosures [Abstract]	'	'
Fair value of short-term and long-term debt, including current maturities	$4.78	$4.61

Contingencies_Additional_Infor

Contingencies - Additional Information (Detail) (USD $)	0 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Jun. 01, 2014	Mar. 25, 2014	Oct. 04, 2014	Dec. 31, 2013
		Defendant	Defendant
			Complaints
			Manufacturers_Distributors
Commitments and Contingencies Disclosure [Abstract]	'	'	'	'
Accrual for environmental loss contingencies, gross	'	'	$19.30	$22.90
Accrued environmental loss contingencies, current	'	'	4.7	6.9
Accrued environmental loss contingencies, noncurrent	'	'	14.6	16
Steel manufacturers, number of manufacturers	'	'	8	'
Additional complaints being filed in July and December of 2010	'	'	2	'
Complaints that are dismissed	'	'	2	'
Defendants that have entered into settlement agreements that are in the process of court approval	'	'	5	'
Number of co-defendants	'	5	'	'
Damages against all defendants jointly and severally	$160.80	$52	'	'

StockBased_Compensation_Additi

Stock-Based Compensation - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
	Oct. 04, 2014	Sep. 28, 2013	Oct. 04, 2014	Sep. 28, 2013
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%	'
Compensation expenses for stock options	$100,000	$0	$7,700,000	$8,600,000
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	500,000	'	500,000	'
Weighted-average recognition period for unrecognized compensation expense related to stock (years)	'	'	'2 years 8 months 12 days	'
Restricted Stock Units [Member]	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'
Unrecognized compensation expense related to stock	33,900,000	'	33,900,000	'
Weighted-average recognition period for unrecognized compensation expense related to stock (years)	'	'	'2 years 2 months 12 days	'
Number of anniversaries of grant date upon which restricted stock units vest	'	'	3	'
Installments in which restricted stock units vest and are converted to common stock	'	'	3	'
Compensation expense	5,300,000	5,300,000	27,800,000	27,500,000
Restricted Stock Units [Member] | AIP [Member]	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'
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 [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 LTIP restricted stock award	'	'	'55 years	'
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	1,000,000	'	1,000,000	'
Weighted-average recognition period for unrecognized compensation expense related to stock (years)	'	'	'1 year 9 months 18 days	'
Compensation expense	$1,800,000	$1,200,000	$4,900,000	$4,500,000

StockBased_Compensation_Schedu

Stock-Based Compensation - Schedule of Stock Option Plans Activity (Detail) (USD $)	9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Oct. 04, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Outstanding at beginning of year, Shares	2,089
Granted, Shares	469
Exercised, Shares	-112
Canceled, Shares	0
Outstanding at end of period, Shares	2,446
Options exercisable at end of period, Shares	1,287
Outstanding at beginning of year, Weighted - Average Exercise Price	$40.47
Granted, Weighted - Average Exercise Price	$50.63
Exercised, Weighted - Average Exercise Price	$40.01
Canceled, Weighted - Average Exercise Price	$0
Outstanding at end of period, Weighted - Average Exercise Price	$42.43
Options exercisable at end of period, Weighted - Average Exercise Price	$40.53
Outstanding at end of period, Weighted - Average Remaining Contractual Life	'7 years 8 months 12 days
Options exercisable at end of period, Weighted - Average Remaining Contractual Life	'6 years 8 months 12 days
Exercised, Aggregate Intrinsic Value	$1,891
Outstanding at end of period, Aggregate Intrinsic Value	23,349
Options exercisable at end of period, Aggregate Intrinsic Value	$14,744

StockBased_Compensation_Summar

Stock-Based Compensation - Summary of Nucor's Restricted Stock Unit Activity (Detail) (USD $)	9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Oct. 04, 2014
Restricted Stock Units [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Unvested at beginning of year, Shares	1,122
Granted, Shares	655
Vested, Shares	-749
Canceled, Shares	-13
Unvested at end of period, Shares	1,015
Unvested at beginning of year, Grant Date Fair Value	$42.51
Granted, Grant Date Fair Value	$50.63
Vested, Grant Date Fair Value	$44.90
Canceled, Grant Date Fair Value	$42.66
Unvested at end of period, Grant Date Fair Value	$45.98
Restricted Stock Units and stock options [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Shares reserved for future grants	11,860

StockBased_Compensation_Summar1

Stock-Based Compensation - Summary of Nucor's Restricted Stock Activity under AIP and LTIP (Detail) (AIP and LTIP [Member], USD $)	9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Oct. 04, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Unvested at beginning of year, Shares	73
Granted, Shares	127
Vested, Shares	-135
Canceled, Shares	0
Unvested at end of period, Shares	65
Shares reserved for future grants	1,111
Restricted Stock And Restricted Stock Units [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Unvested at beginning of year, Grant Date Fair Value	45.49
Granted, Grant Date Fair Value	50.35
Vested, Grant Date Fair Value	48.76
Canceled, Grant Date Fair Value	0
Unvested at end of period, Grant Date Fair Value	48.2

Employee_Benefit_Plan_Addition

Employee Benefit Plan - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Oct. 04, 2014	Sep. 28, 2013	Oct. 04, 2014	Sep. 28, 2013
Employee Benefit Plan [Abstract]	'	'	'	'
Profit Sharing and Retirement Savings Plan, plan expense	$37.30	$22.50	$77.50	$49.20

Interest_Expense_Income_Schedu

Interest Expense (Income) - Schedule of Components of Net Interest Expense (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Oct. 04, 2014	Sep. 28, 2013	Oct. 04, 2014	Sep. 28, 2013
Interest Revenue (Expense), Net [Abstract]	'	'	'	'
Interest expense	$46,624	$38,621	$134,395	$112,978
Interest income	-1,275	-1,154	-3,914	-3,792
Interest expense, net	$45,349	$37,467	$130,481	$109,186

Income_Taxes_Additional_Inform

Income Taxes - Additional Information (Detail) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Oct. 04, 2014	Sep. 28, 2013	Dec. 31, 2013
Income Tax Disclosure [Abstract]	'	'	'
Effective income tax rate	32.10%	28.20%	'
Current deferred tax assets	$259.90	'	$255.50
Current deferred tax Liabilities	13.4	'	14.6
Non-current deferred tax liabilities	$661.90	'	$676.20

Stockholders_Equity_Additional

Stockholders' Equity - Additional Information (Detail) (Nucor-Yamato Steel Company [Member])	Oct. 04, 2014
Nucor-Yamato Steel Company [Member]	'
Stockholders' Equity [Line Items]	'
Noncontrolling interest, ownership percentage by parent	51.00%

Stockholders_Equity_Schedule_o

Stockholders' Equity - Schedule of Changes in Stockholders' Equity (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Oct. 04, 2014	Sep. 28, 2013	Oct. 04, 2014	Sep. 28, 2013
Stockholders' Equity [Line Items]	'	'	'	'
Stockholders' equity, beginning of period	'	'	$7,910,278	$7,885,374
Total comprehensive income	192,812	209,994	476,411	360,897
Stock options	'	'	12,132	8,575
Issuance of stock under award plans, net of forfeitures	'	'	24,242	24,568
Amortization of unearned compensation	'	'	500	601
Dividends declared	'	'	-356,459	-353,424
Distributions to noncontrolling interests	'	'	-51,401	-63,318
Stockholders' equity, end of period	8,015,703	7,863,273	8,015,703	7,863,273
Attributable to Nucor Corporation [Member]	'	'	'	'
Stockholders' Equity [Line Items]	'	'	'	'
Stockholders' equity, beginning of period	'	'	7,645,769	7,641,571
Total comprehensive income	'	'	409,098	283,315
Stock options	'	'	12,132	8,575
Issuance of stock under award plans, net of forfeitures	'	'	24,242	24,568
Amortization of unearned compensation	'	'	500	601
Dividends declared	'	'	-356,459	-353,424
Stockholders' equity, end of period	7,735,282	7,605,206	7,735,282	7,605,206
Attributable to Noncontrolling Interests [Member]	'	'	'	'
Stockholders' Equity [Line Items]	'	'	'	'
Stockholders' equity, beginning of period	'	'	264,509	243,803
Total comprehensive income	'	'	67,313	77,582
Distributions to noncontrolling interests	'	'	-51,401	-63,318
Stockholders' equity, end of period	$280,421	$258,067	$280,421	$258,067

Recovered_Sheet4

Accumulated Other Comprehensive (loss) Income - Components of Accumulated Other Comprehensive (Loss) Income (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Oct. 04, 2014	Sep. 28, 2013	Oct. 04, 2014	Sep. 28, 2013
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]	'	'	'	'
Beginning Balance, Gains and Losses on Hedging Derivatives	($1,400)	$0	$0	$0
Other comprehensive (loss) income before reclassifications, Gains and Losses on Hedging Derivatives	103	0	-1,530	0
Amounts reclassified from accumulated other comprehensive (loss) income into earnings, Gains and Losses on Hedging Derivatives	197	0	430	0
Net current-period other comprehensive (loss) income, Gains and Losses on Hedging Derivatives	300	0	-1,100	0
Ending Balance, Gains and Losses on Hedging Derivatives	-1,100	0	-1,100	0
Beginning Balance, Foreign Currency Gain (Loss)	-19,070	-19,914	-7,438	46,181
Other comprehensive (loss) income before reclassifications, Foreign Currency Gain (Loss)	-81,689	31,879	-93,321	-34,216
Amounts reclassified from accumulated other comprehensive (loss) income into earnings, Foreign Currency Gain (Loss)	0	0	0	0
Net current-period other comprehensive (loss) income, Foreign Currency Gain (Loss)	-81,689	31,879	-93,321	-34,216
Ending Balance, Foreign Currency Gain (Loss)	-100,759	11,965	-100,759	11,965
Beginning Balance, Adjustment to Early Retiree Medical Plan	16,518	10,580	16,518	10,580
Other comprehensive (loss) income before reclassifications, Adjustment to Early Retiree Medical Plan	0	0	0	0
Amounts reclassified from accumulated other comprehensive (loss) income into earnings, Adjustment to Early Retiree Medical Plan	0	0	0	0
Net current-period other comprehensive (loss) income, Adjustment to Early Retiree Medical Plan	0	0	0	0
Ending Balance, Adjustment to Early Retiree Medical Plan	16,518	10,580	16,518	10,580
Beginning Balance	-3,952	-9,334	9,080	56,761
Other comprehensive (loss) income before reclassifications	-81,586	31,879	-94,851	-34,216
Amounts reclassified from accumulated other comprehensive (loss) income into earnings	197	0	430	0
Net current-period other comprehensive (loss) income	-81,389	31,879	-94,421	-34,216
Ending Balance	($85,341)	$22,545	($85,341)	$22,545

Segments_Segments_Detail

Segments - Segments (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Oct. 04, 2014	Sep. 28, 2013	Oct. 04, 2014	Sep. 28, 2013	Dec. 31, 2013
Segment Reporting Information [Line Items]	'	'	'	'	'
Net sales	$5,701,869	$4,940,936	$16,101,388	$14,157,296	'
Earnings before income taxes and noncontrolling interests	403,985	248,202	853,351	553,862	'
Segment assets	15,493,594	'	15,493,594	'	15,203,283
Steel Mills [Member]	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'
Earnings before income taxes and noncontrolling interests	502,703	310,591	1,188,638	819,951	'
Segment assets	8,489,079	'	8,489,079	'	8,365,023
Steel Products [Member]	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'
Earnings before income taxes and noncontrolling interests	63,890	31,018	108,222	51,167	'
Segment assets	3,028,321	'	3,028,321	'	2,861,403
Raw Materials [Member]	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'
Earnings before income taxes and noncontrolling interests	-19,321	-493	-20,597	13,261	'
Segment assets	4,026,534	'	4,026,534	'	3,956,913
Net Sales To External Customers [Member]	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'
Net sales	5,701,869	4,940,936	16,101,388	14,157,296	'
Net Sales To External Customers [Member] | Steel Mills [Member]	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'
Net sales	3,898,031	3,435,884	11,179,935	9,901,471	'
Net Sales To External Customers [Member] | Steel Products [Member]	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'
Net sales	1,142,043	964,153	3,052,135	2,690,604	'
Net Sales To External Customers [Member] | Raw Materials [Member]	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'
Net sales	661,795	540,899	1,869,318	1,565,221	'
Intercompany Eliminations [Member]	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'
Net sales	0	0	0	0	'
Intercompany Eliminations [Member] | Steel Mills [Member]	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'
Net sales	797,396	652,077	2,248,462	1,924,222	'
Intercompany Eliminations [Member] | Steel Products [Member]	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'
Net sales	34,215	24,909	82,257	75,036	'
Intercompany Eliminations [Member] | Raw Materials [Member]	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'
Net sales	2,492,453	2,391,502	7,463,951	6,738,485	'
Intercompany Eliminations [Member] | Corporate/Eliminations [Member]	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'
Net sales	-3,324,064	-3,068,488	-9,794,670	-8,737,743	'
Earnings before income taxes and noncontrolling interests	-143,287	-92,914	-422,912	-330,517	'
Segment assets	($50,340)	'	($50,340)	'	$19,944

Earnings_Per_Share_Computation

Earnings Per Share - Computations of Basic and Diluted Net Earnings Per Share (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Oct. 04, 2014	Sep. 28, 2013	Oct. 04, 2014	Sep. 28, 2013
Earnings Per Share [Abstract]	'	'	'	'
Basic net earnings	$245,447	$147,597	$503,519	$317,531
Earnings allocated to participating securities, Basic	-781	-518	-1,659	-1,324
Net earnings available to common stockholders	244,666	147,079	501,860	316,207
Average shares outstanding	320,023	319,341	319,737	318,979
Basic net earnings per share	$0.76	$0.46	$1.57	$0.99
Diluted net earnings	245,447	147,597	503,519	317,531
Earnings allocated to participating securities, Diluted	-781	-518	-1,659	-1,324
Net earnings available to common stockholders	$244,666	$147,079	$501,860	$316,207
Basic shares outstanding	320,023	319,341	319,737	318,979
Dilutive effect of stock options and other	314	185	288	153
Diluted average shares outstanding	320,337	319,526	320,025	319,132
Diluted net earnings per share	$0.76	$0.46	$1.57	$0.99

Earning_Per_Share_AntiDilutive

Earning Per Share - Anti-Dilutive Stock Options (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Oct. 04, 2014	Sep. 28, 2013	Oct. 04, 2014	Sep. 28, 2013
Earnings Per Share [Abstract]	'	'	'	'
Weighted average shares	0	0	0	183
Weighted average exercise price	$0	$0	$0	$44.51

Subsequent_Events_Additional_I

Subsequent Events - Additional Information (Detail) (Subsequent Event [Member], USD $)	0 Months Ended
In Millions, unless otherwise specified	Oct. 08, 2014	Oct. 08, 2014
	T
Subsequent Event [Member]	'	'
Subsequent Event [Line Items]	'	'
Purchase price	$775.10	'
Issuance of commercial paper	'	$300
Production capacity	1,800,000	'