Basis of Presentation and New Accounting Standards - Schedule of Noncash Operating Activities (Details) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | |
|---|---|---|---|
Dec. 28, 2025 |
Sep. 29, 2025 |
Dec. 29, 2024 |
|
| Accounting Policies [Abstract] | |||
| Decrease in property, plant and equipment from investment tax credit receivables | $ 0.8 | $ 76.8 | $ 223.3 |
| Lease asset and liability additions | 0.8 | 19.1 | 25.0 |
| Lease asset and liability modifications, net | (0.2) | (0.2) | 2.6 |
| Lease termination | (5.0) | (0.1) | 0.0 |
| (Decrease) increase in accrued property, plant and equipment | (3.4) | (82.4) | (111.4) |
| Commitment fee payable for 2030 Senior Notes | 0.0 | 0.0 | 29.3 |
| Fees payable in connection with at-the-market program | $ 0.0 | $ 0.0 | $ 2.4 |