Condensed Consolidated Statements of Earnings - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 28, 2019	Sep. 29, 2018	Sep. 28, 2019	Sep. 29, 2018
Income Statement [Abstract]
Net sales	$ 5,464,502	$ 6,742,202	$ 17,457,112	$ 18,771,395
Costs, expenses and other:
Cost of products sold	4,891,991	5,452,052	15,213,215	15,588,249
Marketing, administrative and other expenses	159,301	234,081	549,020	651,422
Equity in losses (earnings) of unconsolidated affiliates	1,585	(13,634)	(2,459)	(34,157)
Impairment of assets		110,000		110,000
Interest expense, net	31,286	37,201	92,759	103,766
Costs, expenses and other, total	5,084,163	5,819,700	15,852,535	16,419,280
Earnings before income taxes and noncontrolling interests	380,339	922,502	1,604,577	2,352,115
Provision for income taxes	86,752	216,215	367,920	552,101
Net earnings	293,587	706,287	1,236,657	1,800,014
Earnings attributable to noncontrolling interests	18,556	29,631	73,337	86,026
Net earnings attributable to Nucor stockholders	$ 275,031	$ 676,656	$ 1,163,320	$ 1,713,988
Net earnings per share:
Basic	$ 0.90	$ 2.13	$ 3.79	$ 5.37
Diluted	$ 0.90	$ 2.13	$ 3.78	$ 5.35
Average shares outstanding:
Basic	304,637	315,913	305,553	317,928
Diluted	304,980	316,798	306,029	318,882