Condensed Consolidated Statements of Earnings - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 03, 2020	Sep. 28, 2019	Oct. 03, 2020	Sep. 28, 2019
Income Statement [Abstract]
Net sales	$ 4,927,960	$ 5,464,502	$ 14,879,603	$ 17,457,112
Costs, expenses and other:
Cost of products sold	4,425,765	4,891,991	13,370,181	15,213,215
Marketing, administrative and other expenses	165,513	159,301	460,922	549,020
Equity in losses (earnings) of unconsolidated affiliates	(479)	1,585	14,422	(2,459)
Losses on assets	6,604		299,450
Interest expense, net	40,139	31,286	116,856	92,759
Costs, expenses and other, total	4,637,542	5,084,163	14,261,831	15,852,535
Earnings before income taxes and noncontrolling interests	290,418	380,339	617,772	1,604,577
Provision for income taxes	67,788	86,752	207,610	367,920
Net earnings	222,630	293,587	410,162	1,236,657
Earnings attributable to noncontrolling interests	29,215	18,556	87,535	73,337
Net earnings attributable to Nucor stockholders	$ 193,415	$ 275,031	$ 322,627	$ 1,163,320
Net earnings per share:
Basic	$ 0.63	$ 0.90	$ 1.06	$ 3.79
Diluted	$ 0.63	$ 0.90	$ 1.06	$ 3.78
Average shares outstanding:
Basic	303,394	304,637	303,072	305,553
Diluted	303,441	304,980	303,099	306,029