| Cover Page | Nov. 04, 2024 |
| Cover [Abstract] | |
| Document Type | 8-K/A |
| Document Period End Date | Nov. 04, 2024 |
| Entity Registrant Name | Magnera Corporation |
| Entity Incorporation, State or Country Code | PA |
| Entity File Number | 001-03560 |
| Entity Tax Identification Number | 23-0628360 |
| Entity Address, Address Line One | 9335 Harris Corners Pkwy |
| Entity Address, Address Line Two | Ste 300 |
| Entity Address, City or Town | Charlotte |
| Entity Address, State or Province | NC |
| Entity Address, Postal Zip Code | 28269 |
| City Area Code | 866 |
| Local Phone Number | 744-7380 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock |
| Trading Symbol | MAGN |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0000041719 |
| Amendment Flag | false |
