Other Expense, Net (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended	9 Months Ended		12 Months Ended
Other Expense, Net (Details) - USD ($) $ in Millions	Sep. 28, 2025	Sep. 29, 2024	Jun. 30, 2024	Sep. 28, 2025	Sep. 29, 2024	Dec. 29, 2024	Dec. 31, 2023	Sep. 30, 2024
Other Expense, Net [Line Items]
Other expense	$ 1.1						$ 30.7
Other income			$ 2.9
Issuance of a derivative liability								$ 91.5
Forward Purchase Agreements [Member]
Other Expense, Net [Line Items]
Other income							0.4
Related Party [Member]
Other Expense, Net [Line Items]
Other expense		$ 3.0			$ 3.0
Other income	0.0	2.8		$ 0.1	1.8
Issuance of a derivative liability						$ 3.0
Fair value of derivative liabilities						0.3
Related Party [Member] \| Forward Purchase Agreements [Member]
Other Expense, Net [Line Items]
Other expense							30.7
Borrowings and Derivative Liabilities [Member]
Other Expense, Net [Line Items]
Other income		$ 22.8		$ 1.8	$ 22.8
Mergers [Member]
Other Expense, Net [Line Items]
Other expense							0.7
Related party convertible notes and SAFEs [Member]
Other Expense, Net [Line Items]
Other income						$ 0.1	$ 9.1