| Cover | Mar. 30, 2022 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Mar. 30, 2022 |
| Entity Registrant Name | Core & Main, Inc. |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 001-40650 |
| Entity Tax Identification Number | 86-3149194 |
| Entity Address, Address Line One | 1830 Craig Park Court |
| Entity Address, City or Town | St. Louis |
| Entity Address, State or Province | MO |
| Entity Address, Postal Zip Code | 63146 |
| City Area Code | 314 |
| Local Phone Number | 432-4700 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Class A common stock, par value $0.01 per share |
| Trading Symbol | CNM |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0001856525 |
| Amendment Flag | false |
