Debt instrument maturity year.

No definition available.

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- Definition

Line of credit facility expiration month and year.

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Ratio Of Funded Debt To Total Capital

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Ratio On The Limit Of Funded Debt To Capital On Credit Facility

+ References

No definition available.

+ Details

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
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+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(2))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)(2)
-URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258

+ Details

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Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

+ References

+ Details

Name:	us-gaap_DeferredFinanceCostsNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
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-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The maximum amount of borrowing capacity under a line of credit that is available as of the balance sheet date for a specific purpose other than for financing goods acquired for inventory or imminent delivery to a customer.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

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- Definition

Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 3
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

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Period Type:	instant

- Definition

Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

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Balance Type:	credit
Period Type:	instant

- Definition

Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

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Balance Type:	credit
Period Type:	instant

- Definition

Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The cash inflow from additional borrowings, net of cash paid to third parties in connection with debt origination.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3255-108585

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The cash outflow during the period from the repayment of aggregate short-term and long-term debt. Excludes payment of capital lease obligations.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3291-108585

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Reflects the total carrying amount as of the balance sheet date of debt having initial terms less than one year or the normal operating cycle, if longer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
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-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(13))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

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- Details

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- Details

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- Details

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- Details

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Period Type:

- Details

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Balance Type:
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- Details

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Period Type:

- Details

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- Details

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- Details

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Debt and Other Financing Arrangements - Additional Information (Detail) - USD ($)		3 Months Ended	12 Months Ended
	Apr. 30, 2018	Jun. 30, 2018	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Annual aggregate long-term debt maturities - 2019			$ 0
Annual aggregate long-term debt maturities - 2020			20,000,000
Annual aggregate long-term debt maturities - 2021			0
Annual aggregate long-term debt maturities - 2022			601,000,000
Annual aggregate long-term debt maturities - 2023			500,000,000
Annual aggregate long-term debt maturities - thereafter			3,140,000,000
Net proceeds of debt issuances	$ 986,100,000
Debt issuance costs	11,900,000		$ 27,324,000	$ 18,358,000
Ratio funded debt to total capital			30.00%
Credit facilities, amount outstanding			$ 57,870,000	52,833,000
Notes, 3.95%, due 2028 [Member]
Debt Instrument [Line Items]
Debt instrument face amount	$ 500,000,000		$ 500,000,000
Debt instrument interest rate	3.95%		3.95%
Debt instrument - maturity year	2028		2028
Notes, 4.40%, due 2048 [Member]
Debt Instrument [Line Items]
Debt instrument face amount	$ 500,000,000		$ 500,000,000
Debt instrument interest rate	4.40%		4.40%
Debt instrument - maturity year	2048		2048
Notes, 5.85%, due June 1st, 2018 [Member]
Debt Instrument [Line Items]
Debt instrument face amount				$ 500,000,000
Debt instrument interest rate				5.85%
Debt instrument - maturity year				2018
Repayments of debt		$ 500,000,000
Debt instrument - maturity date		Jun. 01, 2018
Harris Steel [Member]
Debt Instrument [Line Items]
Credit facility availability			$ 7,500,000	$ 7,800,000
Credit facilities, amount outstanding			0
Amended and Restated Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Credit facility availability		$ 1,500,000,000
Line of revolving credit facility expiration date		2023-04
Ratio on the limit of funded debt to capital on credit facility		60.00%
Credit facilities, amount outstanding			0	0
Letter of Credit [Member]
Debt Instrument [Line Items]
Credit facility availability		$ 100,000,000
Credit facilities, amount outstanding			56,200,000	40,000,000
Letter of Credit [Member] \| Nucor Trading S.A. [Member]
Debt Instrument [Line Items]
Credit facilities, amount outstanding			$ 57,900,000	$ 52,800,000
Foreign Currency Loans [Member] \| Amended and Restated Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Credit facility availability		850,000,000
Revolving Loans For Nucor Subsidiaries [Member] \| Amended and Restated Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Credit facility availability		500,000,000
Additional Commitments at Nucor's Election in Accordance with Terms of Credit Agreement [Member] \| Amended and Restated Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Credit facility availability		$ 500,000,000