Condensed Consolidated Statements of Earnings - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 01, 2017	Jul. 02, 2016	Jul. 01, 2017	Jul. 02, 2016
Income Statement [Abstract]
Net sales	$ 5,174,769	$ 4,245,772	$ 9,989,948	$ 7,961,348
Costs, expenses and other:
Cost of products sold	4,465,144	3,660,512	8,520,073	7,061,103
Marketing, administrative and other expenses	170,211	161,711	346,637	271,456
Equity in earnings of unconsolidated affiliates	(13,302)	(6,819)	(22,058)	(16,064)
Interest expense, net	44,580	40,484	88,185	85,406
Costs, expenses and other, total	4,666,633	3,855,888	8,932,837	7,401,901
Earnings before income taxes and noncontrolling interests	508,136	389,884	1,057,111	559,447
Provision for income taxes	166,412	118,515	337,739	165,581
Net earnings	341,724	271,369	719,372	393,866
Earnings attributable to noncontrolling interests	18,676	27,749	39,425	62,681
Net earnings attributable to Nucor stockholders	$ 323,048	$ 243,620	$ 679,947	$ 331,185
Net earnings per share:
Basic	$ 1.00	$ 0.76	$ 2.12	$ 1.03
Diluted	$ 1.00	$ 0.76	$ 2.11	$ 1.03
Average shares outstanding:
Basic	320,439	319,360	320,332	319,299
Diluted	321,226	319,583	321,186	319,437
Dividends declared per share	$ 0.3775	$ 0.3750	$ 0.7550	$ 0.7500