Segments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2012	Apr. 02, 2011	Dec. 31, 2011
Segment Reporting Information [Line Items]
Net sales to external customers	$ 5,072,594	$ 4,833,934
Intercompany sales
Earnings (loss) before income taxes and noncontrolling interests	225,062	266,255
Segment assets	14,814,465		14,570,350
Steel Mills [Member]
Segment Reporting Information [Line Items]
Net sales to external customers	3,626,139	3,448,197
Intercompany sales	617,644	584,613
Earnings (loss) before income taxes and noncontrolling interests	390,292	402,881
Segment assets	6,680,986		6,440,868
Steel Products [Member]
Segment Reporting Information [Line Items]
Net sales to external customers	842,245	732,139
Intercompany sales	16,786	10,014
Earnings (loss) before income taxes and noncontrolling interests	(33,044)	(35,895)
Segment assets	2,938,885		2,903,281
Raw Materials [Member]
Segment Reporting Information [Line Items]
Net sales to external customers	482,208	527,463
Intercompany sales	2,882,231	2,777,606
Earnings (loss) before income taxes and noncontrolling interests	14,572	60,254
Segment assets	3,032,485		2,925,651
All Other [Member]
Segment Reporting Information [Line Items]
Net sales to external customers	122,002	126,135
Intercompany sales	2,604	6,425
Earnings (loss) before income taxes and noncontrolling interests	(569)	3,203
Segment assets	205,872		152,107
Corporate/Eliminations [Member]
Segment Reporting Information [Line Items]
Intercompany sales	(3,519,265)	(3,378,658)
Earnings (loss) before income taxes and noncontrolling interests	(146,189)	(164,188)
Segment assets	$ 1,956,237		$ 2,148,443

Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 7

-Section 03

-Paragraph 12

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Topic 210

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-Section S99

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-Publisher FASB

-Paragraph 1

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Concepts (CON)

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-Paragraph 25

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

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Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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-Section S99

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-Subparagraph (SX 210.5-02.18)

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This element represents the income or loss from continuing operations attributable to the economic entity which may also be defined as revenue less expenses from ongoing operations, after income or loss from equity method investments, but before income taxes, extraordinary items, and noncontrolling interest.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

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- Definition

Amount of revenue from transactions with other operating segments of the same entity.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 131

-Paragraph 27

-Subparagraph b

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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Total revenue from sale of goods and services rendered during the reporting period, in the normal course of business, reduced by sales returns and allowances, and sales discounts.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 5

-Section 03

-Paragraph 1

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

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-Section S99

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