Goodwill and Intangible Assets - Purchased Intangible Assets (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Oct. 01, 2023	Sep. 25, 2022	Oct. 01, 2023	Sep. 25, 2022	Dec. 25, 2022
Acquired finite-lived intangible assets:
Gross Value	$ 174.3		$ 174.3		$ 174.3
Accumulated Amortization	(130.5)		(130.5)		(126.0)
Net Value	43.8		43.8		48.3
Total intangible assets, Gross value	181.2		181.2		181.2
Total intangible assets, Net value	50.7		50.7		55.2
Aggregate amortization expense for finite-lived intangible assets	1.5	$ 3.0	4.5	$ 6.3
Trade names
Acquired finite-lived intangible assets:
Indefinite-lived trade names	6.9		6.9		6.9
Customer relationships
Acquired finite-lived intangible assets:
Gross Value	80.9		80.9		80.9
Accumulated Amortization	(62.1)		(62.1)		(60.1)
Net Value	18.8		18.8		20.8
Contracts and backlog
Acquired finite-lived intangible assets:
Gross Value	39.1		39.1		39.1
Accumulated Amortization	(37.6)		(37.6)		(36.3)
Net Value	1.5		1.5		2.8
Developed technology and technical know-how
Acquired finite-lived intangible assets:
Gross Value	33.7		33.7		33.7
Accumulated Amortization	(27.9)		(27.9)		(27.0)
Net Value	5.8		5.8		6.7
Trade names
Acquired finite-lived intangible assets:
Gross Value	3.8		3.8		3.8
Accumulated Amortization	(2.6)		(2.6)		(2.3)
Net Value	1.2		1.2		1.5
In-process research and development
Acquired finite-lived intangible assets:
Gross Value	16.8		16.8		16.8
Accumulated Amortization	(0.3)		(0.3)		(0.3)
Net Value	$ 16.5		$ 16.5		$ 16.5