Derivative Financial Instruments (Narrative) (Detail) (Natural Gas Forward Purchase Contracts, USD $) In Millions, unless otherwise specified	6 Months Ended
Jun. 30, 2012 Month
Natural Gas Forward Purchase Contracts
Derivative [Line Items]
Net deferred losses on cash flow hedges on these contracts that are included in accumulated other comprehensive income that are expected to be reclassified into earnings during the next six months	$ 21.1
Reclassification of earnings, time period, in months	6

The estimated net amount of existing gains or losses on cash flow hedges at the reporting date expected to be reclassified to earnings within the next 6 months.

No definition available.

Name:	nue_CashFlowHedgeGainLossToBeReclassifiedWithinSixMonth
Namespace Prefix:	nue_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration