Segments - Segments (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 28, 2024	Sep. 30, 2023	Sep. 28, 2024	Sep. 30, 2023	Dec. 31, 2023
Segment Reporting Information [Line Items]
Net sales	$ 7,444,160	$ 8,775,734	$ 23,658,415	$ 27,008,970
Earnings (losses) before income taxes and noncontrolling interests	388,273	1,548,082	2,511,777	5,194,648
Total assets	34,346,191		34,346,191		$ 35,340,499
Operating Segments [Member] | Steel Mills [Member]
Segment Reporting Information [Line Items]
Net sales	4,459,509	5,091,479	14,486,492	15,636,508
Earnings (losses) before income taxes and noncontrolling interests	309,123	882,614	2,056,689	3,124,549
Total assets	16,122,916		16,122,916		15,407,266
Operating Segments [Member] | Steel Products [Member]
Segment Reporting Information [Line Items]
Net sales	2,496,160	3,235,969	7,715,804	9,954,828
Earnings (losses) before income taxes and noncontrolling interests	313,972	806,731	1,266,922	2,788,322
Total assets	11,516,513		11,516,513		10,914,870
Operating Segments [Member] | Raw Materials [Member]
Segment Reporting Information [Line Items]
Net sales	488,491	448,286	1,456,119	1,417,634
Earnings (losses) before income taxes and noncontrolling interests	(66,332)	71,367	(17,355)	267,918
Total assets	3,406,496		3,406,496		3,546,759
Intercompany Eliminations [Member] | Steel Mills [Member]
Segment Reporting Information [Line Items]
Net sales	983,070	1,201,648	3,405,794	3,726,346
Intercompany Eliminations [Member] | Steel Products [Member]
Segment Reporting Information [Line Items]
Net sales	124,159	132,481	416,628	333,099
Intercompany Eliminations [Member] | Raw Materials [Member]
Segment Reporting Information [Line Items]
Net sales	2,743,191	2,894,079	8,602,394	9,653,600
Corporate and Eliminations Items [Member]
Segment Reporting Information [Line Items]
Net sales	(3,850,420)	(4,228,208)	(12,424,816)	(13,713,045)
Earnings (losses) before income taxes and noncontrolling interests	(168,490)	$ (212,630)	(794,479)	$ (986,141)
Corporate/eliminations [Member]
Segment Reporting Information [Line Items]
Total assets	$ 3,300,266		$ 3,300,266		$ 5,471,604