Condensed Consolidated Statements of Comprehensive Operations - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 26, 2025	Sep. 27, 2024	Sep. 26, 2025	Sep. 27, 2024
Statement of Comprehensive Income [Abstract]
Net loss	$ (291.1)	$ (26.2)	$ (316.4)	$ (134.9)
Other comprehensive income (loss), net of tax:
Currency translation adjustments	(0.6)	7.6	7.4	(0.7)
Benefit plans	0.0	(0.1)	(0.2)	(0.1)
Total other comprehensive income (loss), net of tax	(0.6)	7.5	7.2	(0.8)
Comprehensive loss	$ (291.7)	$ (18.7)	$ (309.2)	$ (135.7)