Stockholders' Equity - Schedule of Change in Stockholder's Equity (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 29, 2018	Sep. 30, 2017	Sep. 29, 2018	Sep. 30, 2017
Stockholders' Equity [Line Items]
Stockholders' equity, beginning of period			$ 9,084,788	$ 8,254,708
Total comprehensive income	$ 727,712	$ 341,184	1,780,088	1,085,464
Stock options			28,351	13,300
Issuance of stock under award plans, net of forfeitures			44,304	30,787
Amortization of unearned compensation			1,400	1,000
Treasury stock acquired			(351,392)	(90,305)
Dividends declared			(363,624)	(364,046)
Distributions to noncontrolling interests			(49,494)	(85,094)
Stockholders' equity, end of period	10,174,421	8,845,814	10,174,421	8,845,814
Total Nucor Stockholders' Equity [Member]
Stockholders' Equity [Line Items]
Stockholders' equity, beginning of period			8,739,036	7,879,865
Total comprehensive income			1,694,062	1,034,784
Stock options			28,351	13,300
Issuance of stock under award plans, net of forfeitures			44,304	30,787
Amortization of unearned compensation			1,400	1,000
Treasury stock acquired			(351,392)	(90,305)
Dividends declared			(363,624)	(364,046)
Stockholders' equity, end of period	9,792,137	8,505,385	9,792,137	8,505,385
Noncontrolling Interests [Member]
Stockholders' Equity [Line Items]
Stockholders' equity, beginning of period			345,752	374,843
Total comprehensive income			86,026	50,680
Distributions to noncontrolling interests			(49,494)	(85,094)
Stockholders' equity, end of period	$ 382,284	$ 340,429	$ 382,284	$ 340,429