| Cover | Jan. 16, 2025 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Jan. 16, 2025 |
| Entity File Number | 001-38147 |
| Entity Registrant Name | Core Natural Resources, Inc. |
| Entity Central Index Key | 0001710366 |
| Entity Tax Identification Number | 82-1954058 |
| Entity Incorporation, State or Country Code | DE |
| Entity Address, Address Line One | 275 Technology Drive Suite 101 |
| Entity Address, City or Town | Canonsburg |
| Entity Address, State or Province | PA |
| Entity Address, Postal Zip Code | 15317 |
| City Area Code | 724 |
| Local Phone Number | 416-8300 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, $0.01 par value |
| Trading Symbol | CNR |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
