Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	3 Months Ended				6 Months Ended		9 Months Ended
	Jul. 03, 2025	Apr. 03, 2025	Jun. 27, 2024	Mar. 28, 2024	Jul. 03, 2025	Jun. 27, 2024	Sep. 26, 2024	Sep. 28, 2023	Sep. 29, 2022
Adjustments to reconcile net loss to net cash used in operating activities
Depreciation and amortization expense					$ 131.2	$ 155.6
Amortization of deferred financing fees					9.4	3.4
Accretion of customer supply agreement					1.2	1.4
Employee Benefit and Share-based Payment Arrangement, Noncash					15.8	20.7
Loss on Derivative Instruments, Pretax					(0.9)	0.0
Loss (gain) from foreign currency transactions					49.7	(5.3)
Gain (Loss) on Disposition of Property Plant Equipment, Excluding Oil and Gas Property and Timber Property					(1.1)	(0.8)
Deferred taxes					31.0	10.2
Increase (Decrease) in Obligation, Pension and Other Postretirement Benefits					(1.7)	(5.6)
Grant liability amortization					(0.6)	(0.6)
Unrealized Gain (Loss) on Investments					0.3	(0.1)
Increase (Decrease) in Forward Provision					152.5	439.4
Changes in assets and liabilities
Accounts receivable, net					(98.0)	30.6
Inventory, net					(19.8)	(131.9)
Accounts payable and accrued liabilities					84.6	7.6
Profit sharing/deferred compensation					(16.0)	26.1
Advance payments					0.6	20.6
Income taxes receivable/payable					2.4	1.4
Pension plans employer contributions					(23.3)	(11.2)
Other					21.8	(2.3)
Net cash used in operating activities					(563.2)	(981.1)	$ 1,120.9	$ 225.8	$ 394.6
Investing activities
Purchase of property, plant, and equipment					(101.1)	(60.3)
Payment for (Proceeds from) Other Investing Activity					0.4	0.0
Net cash provided by (used in) investing activities					66.4	(60.3)
Financing activities
Principal payments of debt					(26.3)	(30.9)
Repayments of Debt					(3.0)	(1.5)
Repayments of Senior Debt					20.8	0.0
Payment, Tax Withholding, Share-based Payment Arrangement	$ (0.4)	$ (1.0)	$ (0.6)	$ (4.5)	(1.4)	(5.1)
Proceeds from Stock Plans					0.0	3.8
Debt issuance and financing costs					(2.2)	(0.5)
Proceeds from Other Debt				180.0	395.3	465.0
Proceeds from (Payment for) Other Financing Activity					0.0	(1.9)
Net cash provided by financing activities					341.6	428.9
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect					(157.6)	(611.8)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Beginning Balance		$ 566.5		845.9	566.5	845.9	$ 845.9
Cash, cash equivalents, and restricted cash, end of period	408.9		234.1		408.9	234.1
Cash and Cash Equivalents, at Carrying Value, Ending Balance	369.6		206.0		369.6	206.0
Disposal Group, Including Discontinued Operation, Cash and Cash Equivalents	5.9		0.0		5.9	0.0
Reconciliation of Cash, Cash Equivalents, and Restricted Cash [Abstract]
Restricted Cash, Current	0.0		0.0		0.0	0.0
Restricted Cash, Noncurrent	33.4		28.1		33.4	28.1
Increase (Decrease) in Income Taxes Payable					2.4	1.4
Increase (Decrease) in Contract with Customer, Liability					(97.9)	(7.3)
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Assets Transferred to (from) Plan					(2.0)	(1.4)
Repayments of Senior Debt					20.8	0.0
Proceeds from (Payment for) Other Financing Activity					0.0	(1.9)
Proceeds from Other Debt				$ 180.0	395.3	465.0
Increase (Decrease) in Contract with Customer, Asset					(247.5)	498.8
Effect of Exchange Rate on Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation					(2.4)	0.7
Gain (Loss) on Contract Termination					(0.4)	(0.8)
Gain (Loss) on Disposition of Business	129.9		0.0		49.5	0.0
Gain on settlement of New Market Tax Credit incentive program					0.0	(5.7)
Asset Impairment Charges					28.5	0.0
Increase (Decrease) in Deferred Liabilities					(23.3)	(11.2)
Standard Product Warranty Accrual, Increase (Decrease) for Preexisting Warranties					113.8	3.8
Increase (Decrease) in Customer Advances					0.6	20.6
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	$ (630.8)		$ (415.1)		(1,243.5)	(1,031.7)
Proceeds from Divestiture of Businesses					$ 167.1	$ 0.0