Consolidated Statements of Earnings - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Statement [Abstract]
Net sales (Notes 24 and 25)	$ 22,588,858	$ 25,067,279	$ 20,252,393
Costs, expenses and other:
Cost of products sold (Notes 7, 14 and 21)	19,909,773	20,771,871	17,682,986
Marketing, administrative and other expenses (Note 7)	711,248	860,722	687,531
Equity in earnings of unconsolidated subsidiaries	(3,311)	(40,240)	(41,661)
Impairment of assets (Notes 8, 9 and 25)	66,916	110,000
Interest expense, net (Notes 7, 19 and 20)	121,425	135,535	173,580
Costs, expenses and other, total	20,806,051	21,837,888	18,502,436
Earnings before income taxes and noncontrolling interests	1,782,807	3,229,391	1,749,957
Provision for income taxes (Notes 20 and 25)	411,897	748,307	369,386
Net earnings	1,370,910	2,481,084	1,380,571
Earnings attributable to noncontrolling interests	99,767	120,317	61,883
Net earnings attributable to Nucor stockholders	$ 1,271,143	$ 2,360,767	$ 1,318,688
Net earnings per share (Note 22):
Basic	$ 4.14	$ 7.44	$ 4.11
Diluted	$ 4.14	$ 7.42	$ 4.10