| Document and Entity Information | Aug. 07, 2024 |
| Cover [Abstract] | |
| Amendment Flag | false |
| Entity Central Index Key | 0001599617 |
| Document Type | 8-K |
| Document Period End Date | Aug. 07, 2024 |
| Entity Registrant Name | DNOW INC. |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 001-36325 |
| Entity Tax Identification Number | 46-4191184 |
| Entity Address, Address Line One | 7402 North Eldridge Parkway |
| Entity Address, City or Town | Houston |
| Entity Address, State or Province | TX |
| Entity Address, Postal Zip Code | 77041 |
| City Area Code | 281 |
| Local Phone Number | 823-4700 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Security 12b Title | Common Stock, par value $0.01 |
| Trading Symbol | DNOW |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
