Equity Investments (Details)	3 Months Ended				3 Months Ended		3 Months Ended					3 Months Ended		3 Months Ended
	Mar. 31, 2012 USD ($)	Apr. 02, 2011 USD ($)	Mar. 31, 2012 EUR (€)	Dec. 31, 2011 USD ($)	Mar. 31, 2012 NuMit [Member] USD ($)	Dec. 31, 2011 NuMit [Member] USD ($)	Mar. 31, 2012 Duferdofin Nucor S.R.L. [Member] USD ($)	Apr. 02, 2011 Duferdofin Nucor S.R.L. [Member] USD ($)	Mar. 31, 2012 Duferdofin Nucor S.R.L. [Member] EUR (€)	Dec. 31, 2011 Duferdofin Nucor S.R.L. [Member] USD ($)	Dec. 31, 2011 Duferdofin Nucor S.R.L. [Member] EUR (€)	Mar. 31, 2012 Steel Technologies LLC [Member] USD ($)	Mar. 31, 2012 EURO [Member] Duferdofin Nucor S.R.L. [Member] EUR (€)	Mar. 31, 2012 Minimum [Member] Duferdofin Nucor S.R.L. [Member]	Mar. 31, 2012 Maximum [Member] Duferdofin Nucor S.R.L. [Member]
Schedule of Equity Method Investments [Line Items]
Equity method investment	$ 786,000,000			$ 775,700,000	$ 263,000,000	$ 259,300,000	$ 500,000,000			$ 493,900,000
Equity method investment, ownership percentage					50.00%		50.00%					100.00%
Equity method investments, share of net assets							56,500,000
Step-up to fair value of certain assets and liabilities							443,500,000
Step-up to fair value of equity method investment, portion related to identification of goodwill							322,500,000
Notes receivable, related parties												40,000,000
Notes receivable, related parties, interest rate												1.48%		3.08%	3.12%
Basis points in excess of LIBOR on note receivable from related party					90
Amortization expense and other purchase accounting adjustments due to fair value step-up	16,584,000	17,437,000					2,800,000	2,900,000
Interest rate per year in excess of Euribor as of date of the notes							1.00%
Investment in joint venture					221,300,000
Line of credit extended to joint venture												120,000,000
Amended line of credit extended to joint venture												130,000,000
Line of credit extended to joint venture, amount outstanding												92,500,000
Line of credit facility extended to joint venture, interest rate												1.91%
Line of credit facility, maturity period												April 1, 2012
Amended Line of credit facility, maturity period												April 1, 2013
Due from related parties, noncurrent							40,100,000		30,000,000		30,000,000
Notes receivable maturity date					Oct. 21, 2014		Jan. 31, 2016
Equity method investment's credit facilities													112,500,000
Total amount outstanding under equity method investment's credit facilities													106,600,000
Amount outstanding under equity method investment's credit facilities guaranteed by Nucor	$ 71,200,000		€ 53,300,000
Number of sheet processing facilities operated by Steel Technologies					25
Period used for lag basis, in months					1		1