XML 60 R48.htm IDEA: XBRL DOCUMENT
v3.25.0.1

Corporate Expense Allocation (Details) - USD ($) $ in Millions | 3 Months Ended
--- | ---
Dec. 28, 2024 | Dec. 30, 2023
Corporate Expense Allocations [Line Items] |  |
Corporate expense allocation | $ 3 | $ 4
Minimum |  |
Corporate Expense Allocations [Line Items] |  |
Estimated corporate expenses on standalone basis | 17 |
Maximum |  |
Corporate Expense Allocations [Line Items] |  |
Estimated corporate expenses on standalone basis | 22 |
Treasure Holdco, Inc. |  |
Corporate Expense Allocations [Line Items] |  |
Corporate expense allocation | $ 3 | $ 4

X
- Definition Corporate Expense Allocation + References No definition available. + Details
Name: | magn_CorporateExpenseAllocation
Namespace Prefix: | magn_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Corporate Expense Allocations [Line Items] + References No definition available. + Details
Name: | magn_CorporateExpenseAllocationsLineItems
Namespace Prefix: | magn_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Corporate Expenses On Standalone Basis + References No definition available. + Details
Name: | magn_CorporateExpensesOnStandaloneBasis
Namespace Prefix: | magn_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=magn_TreasureHoldcoInc.Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |