Stockholders' Equity - Schedule of Change in Stockholder's Equity (Detail) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 03, 2020	Sep. 28, 2019	Oct. 03, 2020	Sep. 28, 2019
BALANCES, beginning of period	$ 10,623,485	$ 10,698,008	$ 10,791,176	$ 10,201,968
Net earnings	222,630	293,587	410,162	1,236,657
Other comprehensive income (loss)	25,367	(16,006)	(12,503)	(11,519)
Stock options exercised				5,892
Stock option expense	263	275	2,402	4,387
Issuance of stock under award plans, net of forfeitures	11,189	11,339	38,996	59,608
Amortization of unearned compensation	400	500	1,300	1,500
Treasury stock value acquired			(39,499)	(197,511)
Cash dividends declared	(123,039)	(122,809)	(368,774)	(368,707)
Distributions to noncontrolling interests	(43,228)	(3,861)	(106,193)	(71,241)
Other				(1)
BALANCES, end of period	10,717,067	10,861,033	10,717,067	10,861,033
Common Stock [Member]
BALANCES, beginning of period	$ 152,061	$ 152,061	$ 152,061	$ 152,061
BALANCES, shares at beginning of period	380,154	380,154	380,154	380,154
BALANCES, end of period	$ 152,061	$ 152,061	$ 152,061	$ 152,061
BALANCES, shares at end of period	380,154	380,154	380,154	380,154
Additional Paid-in Capital [Member]
BALANCES, beginning of period	$ 2,106,907	$ 2,098,809	$ 2,107,646	$ 2,073,715
Stock options exercised				808
Stock option expense	263	275	2,402	4,387
Issuance of stock under award plans, net of forfeitures	10,012	9,365	6,234	28,540
Amortization of unearned compensation	400	500	1,300	1,500
Other		(1)		(2)
BALANCES, end of period	2,117,582	2,108,948	2,117,582	2,108,948
Retained Earnings [Member]
BALANCES, beginning of period	10,998,533	10,977,950	11,115,056	10,337,445
Net earnings	193,415	275,031	322,627	1,163,320
Cash dividends declared	(123,039)	(122,809)	(368,774)	(368,707)
Other	(1)		(1)	(1,886)
BALANCES, end of period	11,068,908	11,130,172	11,068,908	11,130,172
Accumulated Other Comprehensive Income (Loss) [Member]
BALANCES, beginning of period	(340,836)	(297,760)	(302,966)	(304,133)
Other comprehensive income (loss)	25,367	(16,006)	(12,503)	(11,519)
Other				1,886
BALANCES, end of period	(315,469)	(313,766)	(315,469)	(313,766)
Treasury Stock (at cost) [Member]
BALANCES, beginning of period	$ (2,721,845)	$ (2,630,343)	$ (2,713,931)	$ (2,467,010)
BALANCES, shares at beginning of period	78,259	76,997	78,342	74,562
Stock options exercised				$ 5,084
Stock options exercised (in shares)				(153)
Issuance of stock under award plans, net of forfeitures	$ 1,177	$ 1,974	$ 32,762	$ 31,068
Issuance of stock under award plans, net of forfeitures, shares	(34)	(58)	(942)	(920)
Treasury stock value acquired			$ (39,499)	$ (197,511)
Treasury stock acquired (in shares)			825	3,450
Other		$ 1		$ 1
BALANCES, end of period	$ (2,720,668)	$ (2,628,368)	$ (2,720,668)	$ (2,628,368)
BALANCES, shares at end of period	78,225	76,939	78,225	76,939
Total Nucor Stockholders' Equity [Member]
BALANCES, beginning of period	$ 10,194,820	$ 10,300,717	$ 10,357,866	$ 9,792,078
Net earnings	193,415	275,031	322,627	1,163,320
Other comprehensive income (loss)	25,367	(16,006)	(12,503)	(11,519)
Stock options exercised				5,892
Stock option expense	263	275	2,402	4,387
Issuance of stock under award plans, net of forfeitures	11,189	11,339	38,996	59,608
Amortization of unearned compensation	400	500	1,300	1,500
Treasury stock value acquired			(39,499)	(197,511)
Cash dividends declared	(123,039)	(122,809)	(368,774)	(368,707)
Other	(1)		(1)	(1)
BALANCES, end of period	10,302,414	10,449,047	10,302,414	10,449,047
Noncontrolling Interests [Member]
BALANCES, beginning of period	428,665	397,291	433,310	409,890
Net earnings	29,215	18,556	87,535	73,337
Distributions to noncontrolling interests	(43,228)	(3,861)	(106,193)	(71,241)
Other	1		1
BALANCES, end of period	$ 414,653	$ 411,986	$ 414,653	$ 411,986