Stockholders' Equity - Schedule of Change in Stockholder's Equity (Detail) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 29, 2019	Jun. 30, 2018	Jun. 29, 2019	Jun. 30, 2018
BALANCES, beginning of period	$ 10,502,666	$ 9,322,919	$ 10,201,968	$ 9,084,788
Net earnings	412,277	713,615	943,070	1,093,727
Other comprehensive income (loss)	11,027	(46,666)	4,487	(41,351)
Stock options exercised	2,756		$ 5,892	12,280
Stock options exercised (in shares)			153
Stock option expense	3,800	3,587	$ 4,112	3,937
Issuance of stock under award plans, net of forfeitures	29,554	19,465	48,269	34,706
Amortization of unearned compensation	400	300	1,000	1,000
Treasury stock value acquired	(124,681)	(141,122)	(197,511)	(170,315)
Cash dividends declared	(122,812)	(121,337)	(245,898)	(243,218)
Distributions to noncontrolling interests	(16,978)	(15,337)	(67,380)	(40,130)
Other	(1)		(1)
BALANCES, end of period	10,698,008	9,735,424	10,698,008	9,735,424
Common Stock [Member]
BALANCES, beginning of period	$ 152,061	$ 152,061	$ 152,061	$ 151,960
BALANCES, shares at beginning of period	380,154	380,154	380,154	379,900
Stock options exercised				$ 84
Stock options exercised (in shares)				210
Issuance of stock under award plans, net of forfeitures				$ 17
Issuance of stock under award plans, net of forfeitures, shares				44
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	$ 2,083,339	$ 2,041,297	$ 2,073,715	$ 2,021,339
Stock options exercised	575		808	10,103
Stock option expense	3,800	3,587	4,112	3,937
Issuance of stock under award plans, net of forfeitures	10,696	6,198	19,175	15,003
Amortization of unearned compensation	400	300	1,000	1,000
Other	(1)	1	(1)	1
BALANCES, end of period	2,098,809	2,051,383	2,098,809	2,051,383
Retained Earnings [Member]
BALANCES, beginning of period	10,714,279	8,696,007	10,337,445	8,463,709
Net earnings	386,483	683,153	888,289	1,037,332
Cash dividends declared	(122,812)	(121,337)	(245,898)	(243,218)
Other		(1)	(1,886)	(1)
BALANCES, end of period	10,977,950	9,257,822	10,977,950	9,257,822
Accumulated Other Comprehensive Loss [Member]
BALANCES, beginning of period	(308,787)	(249,366)	(304,133)	(254,681)
Other comprehensive income (loss)	11,027	(46,666)	4,487	(41,351)
Other			1,886
BALANCES, end of period	(297,760)	(296,032)	(297,760)	(296,032)
Treasury Stock [Member]
BALANCES, beginning of period	$ (2,526,701)	$ (1,663,972)	$ (2,467,010)	$ (1,643,291)
BALANCES, shares at beginning of period	75,368	62,056	74,562	61,931
Stock options exercised	$ 2,181		$ 5,084	$ 2,093
Stock options exercised (in shares)	(65)		(153)	(78)
Issuance of stock under award plans, net of forfeitures	$ 18,858	$ 13,267	$ 29,094	$ 19,686
Issuance of stock under award plans, net of forfeitures, shares	(556)	(479)	(862)	(720)
Treasury stock value acquired	$ (124,681)	$ (141,122)	$ (197,511)	$ (170,315)
Treasury stock acquired (in shares)	2,250	2,233	3,450	2,677
BALANCES, end of period	$ (2,630,343)	$ (1,791,827)	$ (2,630,343)	$ (1,791,827)
BALANCES, shares at end of period	76,997	63,810	76,997	63,810
Total Nucor Stockholders' Equity [Member]
BALANCES, beginning of period	$ 10,114,191	$ 8,976,027	$ 9,792,078	$ 8,739,036
Net earnings	386,483	683,153	888,289	1,037,332
Other comprehensive income (loss)	11,027	(46,666)	4,487	(41,351)
Stock options exercised	2,756		5,892	12,280
Stock option expense	3,800	3,587	4,112	3,937
Issuance of stock under award plans, net of forfeitures	29,554	19,465	48,269	34,706
Amortization of unearned compensation	400	300	1,000	1,000
Treasury stock value acquired	(124,681)	(141,122)	(197,511)	(170,315)
Cash dividends declared	(122,812)	(121,337)	(245,898)	(243,218)
Other	(1)		(1)
BALANCES, end of period	10,300,717	9,373,407	10,300,717	9,373,407
Noncontrolling Interest [Member]
BALANCES, beginning of period	388,475	346,892	409,890	345,752
Net earnings	25,794	30,462	54,781	56,395
Distributions to noncontrolling interests	(16,978)	(15,337)	(67,380)	(40,130)
BALANCES, end of period	$ 397,291	$ 362,017	$ 397,291	$ 362,017