Basis of Presentation and Summary of Significant Accounting Policies - Schedule of Non-cash Operating Activities (Details) - USD ($) $ in Millions |
3 Months Ended | 9 Months Ended | 12 Months Ended | |
|---|---|---|---|---|
Sep. 29, 2025 |
Jun. 28, 2026 |
Jun. 29, 2025 |
Jun. 30, 2024 |
|
| Accounting Policies [Abstract] | ||||
| Lease asset and liability additions | $ 19.1 | $ 3.6 | $ 35.2 | $ 5.6 |
| Lease asset and liability modifications, net | (0.2) | 0.2 | 3.2 | 4.4 |
| Lease termination | (0.1) | (5.0) | 0.0 | 0.0 |
| Lease impairment | 0.0 | 0.0 | (4.8) | 0.0 |
| Proceeds from sale of business received in common stock | 0.0 | 0.0 | 0.0 | 60.8 |
| Decrease in property, plant and equipment from investment tax credit receivables | 76.8 | 64.2 | 303.3 | 474.4 |
| Receivable in connection with short-term investment maturities | 0.0 | 0.0 | 0.0 | 25.0 |
| Decrease in property, plant and equipment from long-term incentive related receivables | 0.0 | 0.0 | 0.0 | 114.3 |
| (Decrease) increase in accrued property, plant and equipment | $ (82.4) | $ (32.1) | $ (241.0) | $ 37.3 |