Stockholders' Equity - Schedule of Change in Stockholder's Equity (Detail) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Apr. 03, 2021	Apr. 04, 2020
BALANCES, beginning of period	$ 11,231,861	$ 10,791,176
Net earnings	987,514	54,379
Other comprehensive income (loss)	15,301	(64,661)
Stock options exercised	$ 107,524
Stock options exercised (in shares)	2,135
Stock option expense	$ 333	275
Issuance of stock under award plans, net of forfeitures	15,602	16,189
Amortization of unearned compensation	1,900	400
Treasury stock value acquired	(301,859)	(39,499)
Cash dividends declared	(122,658)	(122,697)
Distributions to noncontrolling interests	(73,795)	(39,493)
BALANCES, end of period	11,861,723	10,596,069
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	$ 2,121,288	$ 2,107,646
Stock options exercised	30,488
Stock option expense	333	275
Issuance of stock under award plans, net of forfeitures	6,900	11,049
Amortization of unearned compensation	1,900	400
BALANCES, end of period	2,160,909	2,119,370
Retained Earnings [Member]
BALANCES, beginning of period	11,343,852	11,115,056
Net earnings	942,432	20,331
Cash dividends declared	(122,658)	(122,697)
BALANCES, end of period	12,163,626	11,012,690
Accumulated Other Comprehensive Income (Loss) [Member]
BALANCES, beginning of period	(118,861)	(302,966)
Other comprehensive income (loss)	15,301	(64,661)
BALANCES, end of period	(103,560)	(367,627)
Treasury Stock (at cost) [Member]
BALANCES, beginning of period	$ (2,709,675)	$ (2,713,931)
BALANCES, shares at beginning of period	77,909	78,342
Stock options exercised	$ 77,036
Stock options exercised (in shares)	(2,135)
Issuance of stock under award plans, net of forfeitures	$ 8,702	$ 5,140
Issuance of stock under award plans, net of forfeitures, shares	(242)	(148)
Treasury stock value acquired	$ (301,859)	$ (39,499)
Treasury stock acquired (in shares)	5,380	825
BALANCES, end of period	$ (2,925,796)	$ (2,748,290)
BALANCES, shares at end of period	80,912	79,019
Total Nucor Stockholders' Equity [Member]
BALANCES, beginning of period	$ 10,788,665	$ 10,357,866
Net earnings	942,432	20,331
Other comprehensive income (loss)	15,301	(64,661)
Stock options exercised	107,524
Stock option expense	333	275
Issuance of stock under award plans, net of forfeitures	15,602	16,189
Amortization of unearned compensation	1,900	400
Treasury stock value acquired	(301,859)	(39,499)
Cash dividends declared	(122,658)	(122,697)
BALANCES, end of period	11,447,240	10,168,204
Noncontrolling Interests [Member]
BALANCES, beginning of period	443,196	433,310
Net earnings	45,082	34,048
Distributions to noncontrolling interests	(73,795)	(39,493)
BALANCES, end of period	$ 414,483	$ 427,865