Segments - Segments (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 29, 2013	Jun. 30, 2012	Jun. 29, 2013	Jun. 30, 2012	Dec. 31, 2012
Segment Reporting Information [Line Items]
Net sales to external customers	$ 4,665,588	$ 5,104,199	$ 9,216,360	$ 10,176,793
Intercompany sales
Earnings before income taxes and noncontrolling interests	152,332	216,193	305,660	441,255
Segment assets	13,766,651		13,766,651		14,152,059
Steel Mills [Member]
Segment Reporting Information [Line Items]
Net sales to external customers	3,197,433	3,615,151	6,465,587	7,363,292
Intercompany sales	639,425	706,755	1,272,145	1,327,003
Earnings before income taxes and noncontrolling interests	237,102	336,508	509,360	726,231
Segment assets	7,873,086		7,873,086		7,870,692
Steel Products [Member]
Segment Reporting Information [Line Items]
Net sales to external customers	937,104	991,444	1,726,451	1,833,689
Intercompany sales	30,855	18,993	50,127	35,779
Earnings before income taxes and noncontrolling interests	32,073	9,202	20,149	(23,842)
Segment assets	2,904,387		2,904,387		2,870,810
Raw Materials [Member]
Segment Reporting Information [Line Items]
Net sales to external customers	531,051	497,604	1,024,322	979,812
Intercompany sales	2,183,495	2,479,148	4,346,983	5,361,379
Earnings before income taxes and noncontrolling interests	12,218	15,116	13,754	29,688
Segment assets	3,641,280		3,641,280		3,379,742
Corporate/Eliminations [Member]
Segment Reporting Information [Line Items]
Intercompany sales	(2,853,775)	(3,204,896)	(5,669,255)	(6,724,161)
Earnings before income taxes and noncontrolling interests	(129,061)	(144,633)	(237,603)	(290,822)
Segment assets	$ (652,102)		$ (652,102)		$ 30,815