Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended
Apr. 04, 2020	Mar. 30, 2019	Dec. 31, 2019
Income Tax Disclosure [Line Items]
Effective income tax rate	62.80%	23.00%
Non-current deferred tax liabilities included in deferred credits and other liabilities	$ 446.5		$ 431.0
Duferdofin Nucor S.r.l. [Member]
Income Tax Disclosure [Line Items]
Impairment of equity method investment	$ 250.0

This item represents an other than temporary decline in value that has been recognized against an investment accounted for under the equity method of accounting. The excess of the carrying amount over the fair value of the investment represents the amount of the write down which is or was reflected in earnings. The written down value is a new cost basis with the adjusted value of the investment becoming its new carrying value subject to the equity accounting method. Evidence of a loss in value might include, but would not necessarily be limited to, absence of an ability to recover the carrying amount of the investment or inability of the investee to sustain an earnings capacity which would justify the carrying amount of the investment.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 35
-Paragraph 32
-URI http://asc.fasb.org/extlink&oid=118954474&loc=d3e32787-111569

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