Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive (Loss) [Member]	Treasury Stock (at cost) [Member]	Total Nucor Stockholders' Equity [Member]	Noncontrolling Interests [Member]
BALANCES, beginning of period at Dec. 31, 2017	$ 9,084,788	$ 151,960	$ 2,021,339	$ 8,463,709	$ (254,681)	$ (1,643,291)	$ 8,739,036	$ 345,752
BALANCES, shares at beginning of period at Dec. 31, 2017		379,900				61,931
Net earnings	2,481,084			2,360,767			2,360,767	120,317
Other comprehensive income (loss)	(49,452)				(49,452)		(49,452)
Stock options exercised	$ 24,102	$ 84	14,675			$ 9,343	24,102
Stock options exercised (in shares)	543	210				(333)
Stock option expense	$ 4,563		4,563				4,563
Issuance of stock under award plans, net of forfeitures	52,313	$ 17	31,361			$ 20,935	52,313
Issuance of stock under award plans, net of forfeitures, shares		44				(762)
Amortization of unearned compensation	1,777		1,777				1,777
Treasury stock value acquired	(853,997)					$ (853,997)	(853,997)
Treasury stock shares acquired						13,726
Cash dividends declared	(487,031)			(487,031)			(487,031)
Distributions to noncontrolling interests	(56,179)							(56,179)
BALANCES, end of period at Dec. 31, 2018	10,201,968	$ 152,061	2,073,715	10,337,445	(304,133)	$ (2,467,010)	9,792,078	409,890
BALANCES, shares at end of period at Dec. 31, 2018		380,154				74,562
Net earnings	1,370,910			1,271,143			1,271,143	99,767
Other comprehensive income (loss)	(718)				(718)		(718)
Stock options exercised	$ 16,146		1,624			$ 14,522	16,146
Stock options exercised (in shares)	425					(425)
Stock option expense	$ 4,662		4,662				4,662
Issuance of stock under award plans, net of forfeitures	62,735		25,637			$ 37,098	62,735
Issuance of stock under award plans, net of forfeitures, shares						(1,095)
Amortization of unearned compensation	2,008		2,008				2,008
Treasury stock value acquired	(298,541)					$ (298,541)	(298,541)
Treasury stock shares acquired						5,300
Cash dividends declared	(491,647)			(491,647)			(491,647)
Distributions to noncontrolling interests	(76,347)							(76,347)
Other				(1,885)	1,885
BALANCES, end of period at Dec. 31, 2019	10,791,176	$ 152,061	2,107,646	11,115,056	(302,966)	$ (2,713,931)	10,357,866	433,310
BALANCES, shares at end of period at Dec. 31, 2019		380,154				78,342
Net earnings	836,028			721,470			721,470	114,558
Other comprehensive income (loss)	184,105				184,105		184,105
Stock options exercised	$ 11,846		2,590			$ 9,256	11,846
Stock options exercised (in shares)	266					(266)
Stock option expense	$ 2,736		2,736				2,736
Issuance of stock under award plans, net of forfeitures	51,898		17,399			$ 34,499	51,898
Issuance of stock under award plans, net of forfeitures, shares						(992)
Amortization of unearned compensation	1,753		1,753				1,753
Treasury stock value acquired	(39,499)					$ (39,499)	(39,499)
Treasury stock shares acquired						825
Cash dividends declared	(492,674)			(492,674)			(492,674)
Distributions to noncontrolling interests	(115,508)							(115,508)
Other			(10,836)				(10,836)	10,836
BALANCES, end of period at Dec. 31, 2020	$ 11,231,861	$ 152,061	$ 2,121,288	$ 11,343,852	$ (118,861)	$ (2,709,675)	$ 10,788,665	$ 443,196
BALANCES, shares at end of period at Dec. 31, 2020		380,154				77,909