Stockholders' Equity - Schedule of Change in Stockholder's Equity (Detail) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Apr. 04, 2020	Mar. 30, 2019
BALANCES, beginning of period	$ 10,791,176	$ 10,201,968
Net earnings	54,379	530,793
Other comprehensive income (loss)	(64,661)	(6,540)
Stock options exercised		3,136
Stock option expense	275	312
Issuance of stock under award plans, net of forfeitures	16,189	18,715
Amortization of unearned compensation	400	600
Treasury stock value acquired	(39,499)	(72,830)
Cash dividends declared	(122,697)	(123,086)
Distributions to noncontrolling interests	(39,493)	(50,402)
BALANCES, end of period	10,596,069	10,502,666
Common Stock [Member]
BALANCES, beginning of period	$ 152,061	$ 152,061
BALANCES, shares at beginning of period	380,154	380,154
BALANCES, end of period	$ 152,061	$ 152,061
BALANCES, shares at end of period	380,154	380,154
Additional Paid-in Capital [Member]
BALANCES, beginning of period	$ 2,107,646	$ 2,073,715
Stock options exercised		233
Stock option expense	275	312
Issuance of stock under award plans, net of forfeitures	11,049	8,479
Amortization of unearned compensation	400	600
BALANCES, end of period	2,119,370	2,083,339
Retained Earnings [Member]
BALANCES, beginning of period	11,115,056	10,337,445
Net earnings	20,331	501,806
Cash dividends declared	(122,697)	(123,086)
Other		(1,886)
BALANCES, end of period	11,012,690	10,714,279
Accumulated Other Comprehensive Income (Loss) [Member]
BALANCES, beginning of period	(302,966)	(304,133)
Other comprehensive income (loss)	(64,661)	(6,540)
Other		1,886
BALANCES, end of period	(367,627)	(308,787)
Treasury Stock (at cost) [Member]
BALANCES, beginning of period	$ (2,713,931)	$ (2,467,010)
BALANCES, shares at beginning of period	78,342	74,562
Stock options exercised		$ 2,903
Stock options exercised (in shares)		(88)
Issuance of stock under award plans, net of forfeitures	$ 5,140	$ 10,236
Issuance of stock under award plans, net of forfeitures, shares	(148)	(306)
Treasury stock value acquired	$ (39,499)	$ (72,830)
Treasury stock acquired (in shares)	825	1,200
BALANCES, end of period	$ (2,748,290)	$ (2,526,701)
BALANCES, shares at end of period	79,019	75,368
Total Nucor Stockholders' Equity [Member]
BALANCES, beginning of period	$ 10,357,866	$ 9,792,078
Net earnings	20,331	501,806
Other comprehensive income (loss)	(64,661)	(6,540)
Stock options exercised		3,136
Stock option expense	275	312
Issuance of stock under award plans, net of forfeitures	16,189	18,715
Amortization of unearned compensation	400	600
Treasury stock value acquired	(39,499)	(72,830)
Cash dividends declared	(122,697)	(123,086)
BALANCES, end of period	10,168,204	10,114,191
Noncontrolling Interests [Member]
BALANCES, beginning of period	433,310	409,890
Net earnings	34,048	28,987
Distributions to noncontrolling interests	(39,493)	(50,402)
BALANCES, end of period	$ 427,865	$ 388,475