Segments - Segments (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 30, 2013	Mar. 31, 2012	Dec. 31, 2012
Segment Reporting Information [Line Items]
Net sales to external customers	$ 4,550,772	$ 5,072,594
Intercompany sales	0
Earnings before income taxes and noncontrolling interests	153,328	225,062
Segment assets	14,039,010		14,152,059
Steel Mills [Member]
Segment Reporting Information [Line Items]
Net sales to external customers	3,268,154	3,748,141
Intercompany sales	632,720	620,248
Earnings before income taxes and noncontrolling interests	272,258	389,723
Segment assets	7,968,804		7,870,692
Steel Products [Member]
Segment Reporting Information [Line Items]
Net sales to external customers	789,347	842,245
Intercompany sales	19,272	16,786
Earnings before income taxes and noncontrolling interests	(11,924)	(33,044)
Segment assets	2,844,926		2,870,810
Raw Materials [Member]
Segment Reporting Information [Line Items]
Net sales to external customers	493,271	482,208
Intercompany sales	2,163,488	2,882,231
Earnings before income taxes and noncontrolling interests	1,536	14,572
Segment assets	3,570,325		3,379,742
Corporate/Eliminations [Member]
Segment Reporting Information [Line Items]
Intercompany sales	(2,815,480)	(3,519,265)
Earnings before income taxes and noncontrolling interests	(108,542)	(146,189)
Segment assets	$ (345,045)		$ 30,815

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

-Section 03

-Paragraph 12

-Article 7

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

-Publisher FASB

-Name Statement of Financial Accounting Concepts (CON)

-Number 6

-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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 18

-Article 5

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.18)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

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

-Section 03

-Paragraph 10

-Article 5

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- 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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Balance Type:	credit
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- Definition

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 FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1)

-URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Article 5

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