Organization and Basis of Presentation (Policies)	12 Months Ended
Organization and Basis of Presentation (Policies)	Dec. 31, 2017
Accounting Policies [Abstract]
Nature of Operations	Nature of Operations NOW Inc. (“NOW” or the “Company”) is a holding company headquartered in Houston, Texas that was incorporated in Delaware on November 22, 2013. NOW operates primarily under the DistributionNOW and Wilson Export brands. NOW is a global distributor of energy products as well as products for industrial applications through its locations in the U.S., Canada and internationally which are geographically positioned to serve the energy and industrial markets in approximately 80 countries. NOW’s energy product offerings are used in the oil and gas industry including upstream drilling and completion, exploration and production, midstream infrastructure development and downstream petroleum refining – as well as in other industries, such as chemical processing, power generation and industrial manufacturing operations. The industrial distribution portion of NOW’s business targets a diverse range of manufacturing and facilities across numerous industries and end markets. NOW also provides supply chain management to drilling contractors, E&P operators, midstream operators, downstream energy and industrial manufacturing companies. NOW’s supplier network consists of thousands of vendors in approximately 40 countries.
Basis of Presentation	Basis of Presentation The accompanying consolidated financial information include the accounts of the Company and its consolidated subsidiaries. All significant intercompany transactions and accounts have been eliminated.
Reclassification	Reclassification Certain amounts in the prior periods presented have been reclassified to conform to the current period financial statement presentation. These reclassifications have no effect on previously reported results of operations.
Recently Issued Accounting Standards	Recently Issued Accounting Standards In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2014-09, Revenue from Contracts with Customers (Topic 606). ASU 2014-09 affects any entity using GAAP that either enters into contracts with customers to transfer goods or services or enters into contracts for the transfer of nonfinancial assets unless those contracts are within the scope of other standards (e.g., insurance contracts or lease contracts). This ASU will supersede the revenue recognition requirements in Revenue Recognition (Topic 605), and most industry-specific guidance. The ASU provides two transition methods: (i) retrospectively to each prior reporting period presented or (ii) retrospectively with the cumulative effect of initially applying this ASU recognized at the date of initial application. In August 2015, the FASB proposed the effective date to be the annual reporting periods beginning after December 15, 2017, and interim periods therein. In May 2016, the FASB issued ASU 2016-12, Narrow-Scope Improvements and Practical Expedients (Topic 606), which clarifies implementation guidance on assessing collectability, presentation of sales tax, noncash consideration and completed contracts and contract modifications at transition. The Company will adopt Topic 606 in the first quarter of fiscal year 2018 pursuant to the aforementioned adoption method (ii). The Company has substantially completed its assessment of the impact of the new standard on key contracts with customers. The Company’s contracts predominantly contain a single delivery element and revenue is recognized at a single point in time when ownership, risks and rewards transfer. These are largely unimpacted by the new standard. The Company will not have a material cumulative adjustment on the consolidated financial statements as a result of the adoption of the new standard. In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842). ASU 2016-02 requires lessees to recognize a lease liability and a right-to-use asset for all leases, including operating leases, with a term greater than twelve months on its balance sheet. ASU 2016-02 is effective for annual and interim periods in fiscal years beginning after December 15, 2018, with early adoption permitted, and requires a modified retrospective transition method. The Company is currently assessing the impact of ASU 2016-02 on its consolidated financial statements. The Company expects that most of its operating lease commitments will be subject to the new standard and recognized as operating lease liabilities and right-of-use assets upon the adoption of ASU 2016-02, which will increase the total assets and total liabilities that are reported relative to such amounts prior to adoption. In June 2016, the FASB issued ASU 2016-13, Measurement of Credit Losses on Financial Instruments (Topic 326), which replaces the incurred loss impairment methodology in current GAAP with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to determine credit loss estimates. ASU 2016-13 requires entities to measure all expected credit losses for financial assets held at the reporting date based on historical experience, current conditions, and reasonable and supportable forecasts. Entities will now use forward-looking information to better form their credit loss estimates. ASU 2016-13 is effective for annual and interim periods in fiscal years beginning after December 15, 2019, with early adoption permitted as of December 15, 2018, and requires modified retrospective transition method. The Company is currently assessing the impact of ASU 2016-13 on its consolidated financial statements. In March 2017, the FASB issued ASU 2017-07, Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost (Topic 715). ASU 2017-07 requires the disaggregation of the service cost component from the other components of net periodic benefit cost and allows only the service cost component of net benefit cost to be eligible for capitalization. ASU 2017-07 is effective for annual and interim periods in fiscal years beginning after December 15, 2017. The Company sponsors two defined benefit plans in the UK under which accrual of pension benefits has ceased and there will not be a service cost component to the net periodic pension cost. Plan members benefits that have previously been accrued are indexed in line with inflation during the period up to retirement in order to protect their purchasing power. The Company plans to adopt this standard in the first quarter of fiscal year 2018 and does not expect a material effect on its consolidated financial statements.
Recently Adopted Accounting Standards	Recently Adopted Accounting Standards In July 2015, the FASB issued ASU 2015-11, Simplifying the Measurement of Inventory (Topic 330). Under ASU 2015-11, inventory will be measured at the “lower of cost and net realizable value.” ASU 2015-11 defines net realizable value as the “estimated selling prices in the ordinary course of business, less reasonably predictable costs of completion, disposal, and transportation.” ASU 2015-11 is effective for annual and interim periods in fiscal years beginning after December 15, 2016. The Company adopted this standard as of January 1, 2017, with no material impact on its consolidated financial statements. In October 2016, the FASB issued ASU 2016-16, Intra-Entity Transfers of Assets Other than Inventory (Topic 740), to recognize the income tax consequences of intra-entity transfers of an asset other than inventory when the transfer occurs. ASU 2016-16 is effective for annual and interim periods in fiscal years beginning after December 15, 2017 with early adoption permitted in the first interim period of fiscal year 2017. Upon adoption, any deferred charge established upon the intra-company transfer would be recorded as a cumulative-effect adjustment to retained earnings. The Company early adopted this standard in the first quarter of fiscal year 2017 and reversed a deferred charge of $1 million previously recorded in prepaid and other current assets in the accompanying consolidated balance sheets. However, due to the Company’s full valuation allowance in the U.S., the deferred charge recorded as a cumulative-effect adjustment to accumulated deficit netted to zero. In January 2017, the FASB issued ASU 2017-04, Simplifying the Test for Goodwill Impairment (Topic 350), which eliminates Step 2 from the goodwill impairment test. ASU 2017-04 is effective for annual and interim periods in fiscal years beginning after December 15, 2019. Early adoption is permitted for interim or annual goodwill impairment tests performed after January 1, 2017 and should be applied prospectively. The Company early adopted this standard as of January 1, 2017, for use in its goodwill impairment testing.
Cash and Cash Equivalents	Cash and Cash Equivalents Cash and Cash Equivalents consist of all highly liquid investments with maturities of three months or less at the date of purchase.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The carrying amounts of cash and cash equivalents, receivables and payables approximated fair value because of the relatively short maturity of these instruments. See Note 12 “Derivative Financial Instruments” for the fair value of derivative financial instruments.
Inventories	Inventories Inventories consist primarily of oilfield and industrial finished goods. Inventories are stated at the lower of cost or net realizable value and using average cost methods. Allowances for excess and obsolete inventories are determined based on the Company’s historical usage of inventory on hand as well as its future expectations.
Property, Plant and Equipment	Property, Plant and Equipment Property, plant and equipment are stated at cost. Expenditures for major improvements that extend the lives of property and equipment are capitalized while minor replacements, maintenance and repairs are charged to expense as incurred. Disposals are removed at cost less accumulated depreciation with any resulting gain or loss reflected in the results of operations for the respective period. Depreciation is provided using the straight-line method over the estimated useful lives of individual items.
Long-Lived Assets, Including Goodwill and Other Acquired Intangible Assets	Long-Lived Assets, Including Goodwill and Other Acquired Intangible Assets The Company evaluates the recoverability of property, plant and equipment and amortizable intangible assets for possible impairment whenever events or circumstances indicate that the carrying amount of such assets may not be recoverable. Recoverability of these assets is measured by a comparison of the carrying amounts to the future undiscounted cash flows the assets are expected to generate. If such review indicates that the carrying amount of property and equipment and intangible assets is not recoverable, the carrying amount of such assets is reduced to fair value. The Company has not recorded any such impairment charge during the years presented. The Company conducts impairment testing for goodwill annually in the fourth quarter of its fiscal year and more frequently, on an interim basis, when an event occurs or circumstances change that indicate that the fair value of a reporting unit may have declined below its carrying value. Events or circumstances which could indicate a probable impairment include, but are not limited to, a significant reduction in worldwide oil and gas prices or drilling; a significant reduction in profitability or cash flow of oil and gas companies or drilling contractors; a significant reduction in worldwide well remediation activity; a significant reduction in capital investment by other oilfield service companies; or a significant increase in worldwide inventories of oil or gas. The Company tests goodwill at the reporting unit level, which is defined as an operating segment or one level below an operating segment that constitutes a business for which financial information is available and is regularly reviewed by management. The Company determined that it has five reporting units for this purpose—United States Energy, United States Supply Chain, United States Process Solutions, Canada and International. Before testing goodwill, the Company considers whether or not to first assess qualitative factors to determine whether the existence of events or circumstances leads to a determination that it is more-likely-than-not that the fair value of a reporting unit is less than its carrying amount and whether an impairment test is required. Subsequent to the adoption of ASU 2017-04, the goodwill impairment test was simplified to a one-step approach. The Company compares the fair value of the reporting unit to the carrying value of a reporting unit to determine if there is impairment. If the fair value exceeds the carrying amount, then goodwill is not considered impaired. If the carrying amount of a reporting unit exceeds the fair value, an impairment loss is recognized in an amount equal to that excess. The impairment loss recognized will not exceed the total amount of goodwill allocated to that reporting unit. Prior to the adoption of ASU 2017-04, the goodwill impairment test was a two-step process. The first step was to identify if a potential impairment exists by comparing the fair value of the reporting unit with its carrying amount, including goodwill. If the fair value of a reporting unit exceeds its carrying amount, goodwill of the reporting unit was not considered to have a potential impairment and the second step of the impairment test is not necessary. However if the carrying amount of a reporting unit exceeds its fair value, the second step was performed to determine if goodwill is impaired and to measure the amount of impairment loss to recognize, if any. The second step compared the implied fair value of goodwill with the carrying amount of goodwill. If the implied fair value of goodwill exceeded the carrying amount, then goodwill was not considered impaired. However, if the carrying amount of goodwill exceeds the implied fair value, an impairment loss was recognized in an amount equal to that excess. When performing goodwill impairment testing, the fair values of reporting units are determined based on valuation techniques using the best available information, including discounted cash flow projections. The discounted cash flow is based on management’s short-term and long-term forecast of operating performance for each reporting unit. The two main assumptions used in measuring goodwill impairment, which bear the risk of change and could impact the Company’s goodwill impairment analysis, include the cash flow from operations from each of the Company’s individual business units and the discount rate. The starting point for each of the reporting unit’s cash flow from operations is the detailed annual plan or updated forecast. The detailed planning and forecasting process takes into consideration a multitude of factors including worldwide rig activity, inflationary forces, pricing strategies, customer analysis, operational issues, competitor analysis, capital spending requirements, working capital requirements and customer needs among other items which impact the individual reporting unit projections. Cash flows beyond the specific operating plans were estimated using a terminal value calculation, which incorporated historical and forecasted financial cyclical trends for each reporting unit and considered long-term earnings growth rates. The financial and credit market volatility impacts the fair value measurement by adjusting the discount rate. During times of volatility, significant judgment must be applied to determine whether credit changes are a short-term or long-term trend. The Company makes significant assumptions and estimates about the extent and timing of future cash flows, growth rates, and discount rates all of which represent unobservable inputs into valuation methodologies and are classified as level 3 inputs under the fair value hierarchy. In evaluating the reasonableness of the Company’s fair value estimates, the Company considers, among other factors, the relationship between the market capitalization of the Company and the estimated fair value of its reporting units. In addition to the recoverability assessment, the Company routinely reviews the remaining estimated useful lives of property, plant and equipment and amortizable intangible assets. If the Company reduces the estimated useful life assumption for any asset, the remaining unamortized balance is amortized or depreciated over the revised estimated useful life.
Foreign Currency	Foreign Currency The functional currency for most of the Company’s foreign operations is the local currency. Certain foreign operations use the U.S. dollar as the functional currency. For those that have local currency as functional the cumulative effects of translating the balance sheet accounts from the functional currency into the U.S. dollar at current exchange rates are included in accumulated other comprehensive income (loss). Revenues and expenses are translated at average exchange rates in effect during the period. Accordingly, financial statements of these foreign subsidiaries are remeasured to U.S. dollars for consolidation purposes using current rates of exchange for monetary assets and liabilities and historical rates of exchange for nonmonetary assets and related elements of expense. Revenue and expense elements are remeasured at rates that approximate the rates in effect on the transaction dates. For all operations, gains or losses, from remeasuring foreign currency transactions into the reporting currency, are included in other expense. Net foreign currency transaction losses were $2 million, $1 million and $3 million for the years ending December 31, 2017, 2016 and 2015, respectively, and are included in other expense in the accompanying consolidated statements of operations.
Revenue Recognition	Revenue Recognition The Company sells products through store fronts, on-site and eCommerce. The Company recognizes revenue when persuasive evidence of an arrangement exists, delivery has occurred, the sales price is fixed or determinable, and collectability is reasonably assured. Generally, across every channel, these conditions are met when the product is shipped, delivered, or picked up by the customer. Revenues are presented net of return allowances and include freight charges billed to customers. Sales tax collected from customers is excluded from revenue in the accompanying consolidated statements of operations.
Cost of Products	Cost of Products Cost of products includes the cost of inventory sold and related items, such as vendor consideration, inventory allowances, amortization of intangibles and inbound and outbound freight.
Warehousing, Selling and Administrative Expenses	Warehousing, Selling and Administrative Expenses Warehousing, selling and administrative costs include branch location, distribution center and regional expenses (including costs such as compensation, benefits and rent) as well as corporate general selling and administrative expenses.
Vendor Consideration	Vendor Consideration The Company receives funds from vendors in the normal course of business, principally as a result of purchase volumes. Generally, these vendor funds do not represent the reimbursement of specific, incremental and identifiable costs incurred by the Company to sell the vendor’s product. Therefore, the Company treats these funds as a reduction of inventory when purchased and once these goods are sold to third parties the associated amount is credited to cost of products. The Company develops accrual rates for vendor consideration based on the provisions of the arrangements in place, historical trends, purchases and future expectations. Due to the complexity and diversity of the individual vendor agreements, the Company performs analyses and reviews historical trends throughout the year and confirms actual amounts with select vendors to ensure the amounts earned are appropriately recorded. Amounts accrued throughout the year could be impacted if actual purchase volumes differ from projected annual purchase volumes, especially in the case of programs that provide for increased funding when graduated purchase volumes are met.
Income Taxes	Income Taxes The liability method is used to account for income taxes. Deferred tax assets and liabilities are determined based on differences between the financial reporting and tax basis of assets and liabilities and are measured using the enacted tax rates that will be in effect when the differences are expected to reverse. Valuation allowances are established when necessary to reduce deferred tax assets to amounts which are more-likely-than-not to be realized.
Concentration of Credit Risk	Concentration of Credit Risk The Company grants credit to its customers, which operate primarily in the energy, industrial and manufacturing markets. Concentrations of credit risk are limited because the Company has a large number of geographically diverse customers, thus spreading trade credit risk. The Company controls credit risk through credit evaluations, credit limits and monitoring procedures. The Company performs periodic credit evaluations of its customers’ financial condition and generally does not require collateral, but may require letters of credit for certain sales. Credit losses are provided for in the financial statements. Allowances for doubtful accounts are determined based on a continuous process of assessing the Company’s portfolio on an individual customer basis taking into account current market conditions and trends. This process consists of a thorough review of historical collection experience, current aging status of the customer accounts, and financial condition of the Company’s customers. Based on a review of these factors, the Company will establish or adjust allowances for specific customers. Balances that remain outstanding after the Company has used reasonable collection efforts are written off through a charge to the allowance and a credit to receivables. No single customer represents more than 10% of the Company’s revenue. The Company’s top 30 customers in aggregate represent approximately one-third of the Company’s revenue.
Stock-Based Compensation	Stock-Based Compensation Compensation expense for the Company’s stock-based compensation plans is measured using the fair value method required by ASC Topic 718 “Compensation—Stock Compensation”. Under this guidance the fair value of the award is measured on the grant date and amortized to expense using the straight-line method over the shorter of the vesting period or the remaining requisite service period. Forfeitures are recognized as they occur.
Environmental Liabilities	Environmental Liabilities When environmental assessments or remediations are probable and the costs can be reasonably estimated, remediation liabilities are recorded on an undiscounted basis and are adjusted as further information develops or circumstances change.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect reported and contingent amounts of assets and liabilities as of the date of the financial statements and reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.
Contingencies	Contingencies The Company accrues for costs relating to litigation claims and other contingent matters, when such liabilities become probable and reasonably estimable. Such estimates may be based on advice from third parties or on management’s judgment, as appropriate. Revisions to contingent liabilities are reflected in income in the period in which different facts or information become known or circumstances change that affect the Company’s previous judgments with respect to the likelihood or amount of loss. Amounts paid upon the ultimate resolution of contingent liabilities may be materially different from previous estimates and could require adjustments to the estimated reserves to be recognized in the period such new information becomes known. In circumstances where the most likely outcome of a contingency can be reasonably estimated, the Company accrues a liability for that amount. Where the most likely outcome cannot be estimated, a range of potential losses is established and if no one amount in that range is more likely than others, the low end of the range is accrued.
Accumulated Other Comprehensive Income (Loss)	The Company’s reporting currency is the U.S. dollar. A majority of the Company’s international entities in which there is a substantial investment have the local currency as their functional currency. As a result, foreign currency translation adjustments resulting from the process of translating the entities’ financial statements into the reporting currency are reported in other comprehensive income (loss) in accordance with ASC Topic 830 “Foreign Currency Matters”.