Condensed Consolidated Statements of Earnings - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 30, 2019	Mar. 31, 2018
Income Statement [Abstract]
Net sales	$ 6,096,624	$ 5,568,419
Costs, expenses and other:
Cost of products sold	5,200,732	4,842,013
Marketing, administrative and other expenses	180,739	182,960
Equity in earnings of unconsolidated affiliates	(2,906)	(9,580)
Interest expense, net	28,443	37,114
Costs, expenses and other, total	5,407,008	5,052,507
Earnings before income taxes and noncontrolling interests	689,616	515,912
Provision for income taxes	158,823	135,800
Net earnings	530,793	380,112
Earnings attributable to noncontrolling interests	28,987	25,933
Net earnings attributable to Nucor stockholders	$ 501,806	$ 354,179
Net earnings per share:
Basic	$ 1.63	$ 1.11
Diluted	$ 1.63	$ 1.10
Average shares outstanding:
Basic	306,585	319,421
Diluted	307,180	320,474