Business Segments (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2023	Oct. 01, 2023	Jul. 02, 2023	Apr. 02, 2023	Jan. 01, 2023	Oct. 02, 2022	Jul. 03, 2022	Apr. 03, 2022	Dec. 31, 2023	Jan. 01, 2023	Jan. 02, 2022
Segment Reporting Information [Line Items]
Sales	$ 1,064.0	$ 1,025.6	$ 1,046.0	$ 1,038.1	$ 1,010.4	$ 1,032.0	$ 959.5	$ 834.1	$ 4,173.7	$ 3,836.0	$ 2,799.8
Operating Segments
Segment Reporting Information [Line Items]
Sales									4,638.9	4,249.4	3,010.7
Operating Segments | Intersegment Sales [Member]
Segment Reporting Information [Line Items]
Sales									465.2	413.4	210.9
Operating Segments | External Sales [Member]
Segment Reporting Information [Line Items]
Sales									4,173.7	3,836.0	2,799.8
Operating Segments | High Performance Materials & Components
Segment Reporting Information [Line Items]
Sales									2,302.0	1,815.7	1,248.3
Operating Segments | High Performance Materials & Components | Intersegment Sales [Member]
Segment Reporting Information [Line Items]
Sales									181.8	174.5	93.2
Operating Segments | High Performance Materials & Components | External Sales [Member]
Segment Reporting Information [Line Items]
Sales									2,120.2	1,641.2	1,155.1
Operating Segments | Advanced Alloys & Solutions [Member]
Segment Reporting Information [Line Items]
Sales									2,336.9	2,433.7	1,762.4
Operating Segments | Advanced Alloys & Solutions [Member] | Intersegment Sales [Member]
Segment Reporting Information [Line Items]
Sales									283.4	238.9	117.7
Operating Segments | Advanced Alloys & Solutions [Member] | External Sales [Member]
Segment Reporting Information [Line Items]
Sales									$ 2,053.5	$ 2,194.8	$ 1,644.7