Goodwill and Intangible Assets - Purchased Intangible Assets (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 25, 2022	Sep. 26, 2021	Sep. 25, 2022	Sep. 26, 2021	Dec. 26, 2021
Acquired finite-lived intangible assets:
Gross Value	$ 180.0		$ 180.0		$ 155.0
Accumulated Amortization	(125.0)		(125.0)		(118.7)
Net Value	55.0		55.0		36.3
Total intangible assets: gross value	186.9		186.9		161.9
Total intangible assets: net value	61.9		61.9		43.2
Aggregate amortization expense for finite-lived intangible assets	3.0	$ 1.1	6.3	$ 3.7
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	80.5		80.5		76.5
Accumulated Amortization	(59.5)		(59.5)		(57.6)
Net Value	21.0		21.0		18.9
Contracts and backlog
Acquired finite-lived intangible assets:
Gross Value	43.9		43.9		34.9
Accumulated Amortization	(36.1)		(36.1)		(33.1)
Net Value	7.8		7.8		1.8
Developed technology and technical know-how
Acquired finite-lived intangible assets:
Gross Value	39.6		39.6		31.4
Accumulated Amortization	(26.8)		(26.8)		(25.8)
Net Value	12.8		12.8		5.6
Trade names
Acquired finite-lived intangible assets:
Gross Value	5.0		5.0		2.7
Accumulated Amortization	(2.4)		(2.4)		(2.0)
Net Value	2.6		2.6		0.7
In-process research and development
Acquired finite-lived intangible assets:
Gross Value	11.0		11.0		9.5
Accumulated Amortization	(0.2)		(0.2)		(0.2)
Net Value	$ 10.8		$ 10.8		$ 9.3