Business Segments (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 29, 2025	Jun. 30, 2024	Jun. 29, 2025	Jun. 30, 2024
Segment Reporting Information [Line Items]
Sales	$ 1,140.4	$ 1,095.3	$ 2,284.8	$ 2,138.2
Segment EBITDA	220.7	201.3	435.1	370.7
Corporate expenses	(15.4)	(19.4)	(32.8)	(36.5)
Closed operations and other income (expenses)	2.4	0.7	0.0	(0.6)
Depreciation & amortization	(41.6)	(37.9)	(82.4)	(73.9)
Interest expense, net	(25.4)	(28.4)	(48.4)	(55.0)
Restructuring and other charges	(7.4)	(5.4)	(13.0)	(8.5)
Loss on sales of businesses, net	0.0	0.0	(3.7)	0.0
Income before taxes	133.3	110.9	254.8	196.2
Operating Segments
Segment Reporting Information [Line Items]
Sales	1,240.6	1,248.4	2,502.3	2,381.0
Depreciation & amortization	(41.6)	(37.9)	(82.4)	(73.9)
Operating Segments \| HPMC
Segment Reporting Information [Line Items]
Sales	662.1	643.8	1,306.1	1,215.7
Allocated corporate overhead	18.5	17.1	34.3	32.5
Other segment items	499.6	512.9	996.8	971.8
Segment EBITDA	144.0	113.8	275.0	211.4
Depreciation & amortization	(20.9)	(17.9)	(40.6)	(34.2)
Operating Segments \| AA&S
Segment Reporting Information [Line Items]
Sales	578.5	604.6	1,196.2	1,165.3
Allocated corporate overhead	19.9	17.5	36.0	32.4
Other segment items	481.9	499.6	1,000.1	973.6
Segment EBITDA	76.7	87.5	160.1	159.3
Depreciation & amortization	(19.1)	(18.3)	(38.6)	(36.3)
Sales to external customers \| Operating Segments
Segment Reporting Information [Line Items]
Sales	1,140.4	1,095.3	2,284.8	2,138.2
Sales to external customers \| Operating Segments \| HPMC
Segment Reporting Information [Line Items]
Sales	608.8	562.0	1,192.9	1,091.9
Sales to external customers \| Operating Segments \| AA&S
Segment Reporting Information [Line Items]
Sales	531.6	533.3	1,091.9	1,046.3
Intersegment sales \| Operating Segments
Segment Reporting Information [Line Items]
Sales	100.2	153.1	217.5	242.8
Intersegment sales \| Operating Segments \| HPMC
Segment Reporting Information [Line Items]
Sales	53.3	81.8	113.2	123.8
Intersegment sales \| Operating Segments \| AA&S
Segment Reporting Information [Line Items]
Sales	$ 46.9	$ 71.3	$ 104.3	$ 119.0

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