Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 25, 2022
Deferred tax assets:
Accounts receivable	$ 31.8	$ 28.8
Inventories	33.2	22.6
Loss and credit carryforwards	461.9	175.3
Operating leases	3.5	11.2
Operating expenses	19.1	29.9
Pension	6.9	9.1
Other compensation	46.4	50.7
Postretirement benefits	5.9	5.7
Interest rate hedge	4.8	4.5
Tax sharing agreement	0.3	0.3
Deferred revenue	0.4	4.4
Capitalized research and experimentation	100.6	81.2
Depreciation and amortization of long-lived assets	192.0	63.2
Interest expense limitation	28.7	0.0
Other	3.7	11.7
Gross deferred tax assets	939.2	498.6
Deferred tax liabilities:
Depreciation and amortization of long-lived assets	108.0	125.0
Equity method investment	19.0	14.9
Operating leases	1.1	9.3
Prepaid expenses	4.0	4.4
Other	22.8	15.4
Gross deferred tax liabilities	154.9	169.0
Valuation allowance	(432.0)	(189.8)
Net deferred income taxes	$ 352.3	$ 139.8