| Document and Entity Information - USD ($) $ in Billions | 12 Months Ended | | |
| Dec. 31, 2024 | Feb. 07, 2025 | Jun. 28, 2024 |
| Cover [Abstract] | | | |
| Document Type | 10-K/A | | |
| Amendment Flag | true | | |
| Amendment Description | DNOW Inc. (the “Company”) is filing this Amendment No. 1 on Form 10-K/A (this “Amendment”) to amend the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2024 (the “Original Filing”), which was filed with the U.S. Securities and Exchange Commission (the “SEC”) on February 18, 2025 (the “Original Filing Date”). The sole purpose of this Amendment is to supplement the Exhibits contained in Item 15(a)(3) of Part IV of the Original Filing to include our Insider Trading Policies as Exhibits 19, which were inadvertently omitted in the Original Filing.This Amendment is an exhibit-only filing. Except as described above, no changes have been made to the Original Filing and this Amendment does not modify, amend, or update in any way any of the financial or other information contained in the Original Filing. This Amendment does not reflect events that may have occurred subsequent to the Original Filing Date. Accordingly, this Amendment should be read in conjunction with the Original Filing and the Company’s other filings with the SEC.Pursuant to Rule 12b-15 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), currently dated certifications are filed herewith as exhibits to this Amendment pursuant to Rule 13a-14(a) or 15d-14(a) of the Exchange Act under Item 15 of Part IV hereof. Because no financial statements have been included in this Amendment and this Amendment does not contain any disclosure with respect to Items 307 and 308 of Regulation S-K, paragraphs 3, 4, and 5 of the certifications have been omitted. Similarly, because no financial statements have been included in this Amendment, certifications pursuant to Section 906 of the Sarbanes-Oxley Act of 2002 have been omitted. | | |
| Document Period End Date | Dec. 31, 2024 | | |
| Document Fiscal Year Focus | 2024 | | |
| Document Fiscal Period Focus | FY | | |
| Entity Registrant Name | DNOW INC. | | |
| Entity Central Index Key | 0001599617 | | |
| Entity Current Reporting Status | Yes | | |
| Entity Voluntary Filers | No | | |
| Entity Interactive Data Current | Yes | | |
| Current Fiscal Year End Date | --12-31 | | |
| Entity Filer Category | Large Accelerated Filer | | |
| Entity Well-known Seasoned Issuer | Yes | | |
| Entity Public Float | | | $ 1.5 |
| Entity Common Stock, Shares Outstanding | | 105,687,410 | |
| Entity Shell Company | false | | |
| Entity Small Business | false | | |
| Entity Emerging Growth Company | false | | |
| Title of 12(b) Security | Common Stock, par value $0.01 | | |
| Trading Symbol | DNOW | | |
| Security Exchange Name | NYSE | | |
| Entity File Number | 001-36325 | | |
| Entity Incorporation, State or Country Code | DE | | |
| 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 | | |
| Document Annual Report | true | | |
| Document Transition Report | false | | |
| ICFR Auditor Attestation Flag | true | | |
| Documents Incorporated by Reference | Documents Incorporated by Reference Portions of the Proxy Statement in connection with the 2025 Annual Meeting of Stockholders are incorporated in Part III of this report. | | |
| Document Financial Statement Error Correction [Flag] | false | | |
