Name:	dnow_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentCurrentAssets
Namespace Prefix:	dnow_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

This element represents the amount of any measurement period adjustment (as defined) realized during the reporting period to current liabilities assumed in connection with a business combination for which the initial accounting was incomplete.

No definition available.

Name:	dnow_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentCurrentLiabilities
Namespace Prefix:	dnow_
Data Type:	xbrli:monetaryItemType
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Business combination provisional information initial accounting incomplete adjustment goodwill.

No definition available.

Name:	dnow_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentGoodwill
Namespace Prefix:	dnow_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Business combination provisional information initial accounting incomplete adjustment purchase price.

No definition available.

Name:	dnow_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentPurchasePrice
Namespace Prefix:	dnow_
Data Type:	xbrli:monetaryItemType
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Period Type:	duration

Net purchase price.

No definition available.

Name:	dnow_NetPurchasePrice
Namespace Prefix:	dnow_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6388964&loc=d3e16225-109274

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
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-Section 45
-Paragraph 28
-Subparagraph (b)
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-Name Accounting Standards Codification
-Topic 350
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-Paragraph 2
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Name:	us-gaap_AmortizationOfIntangibleAssets
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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

Name:	us-gaap_BusinessAcquisitionLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

This element represents the amount of any measurement period adjustment (as defined) realized during the reporting period to property, plant, and equipment acquired in connection with a business combination for which the initial accounting was incomplete.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 20
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-Paragraph 4A
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-URI http://asc.fasb.org/extlink&oid=73530397&loc=SL65897772-128472

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The amount of identifiable intangible assets recognized as of the acquisition date.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
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Data Type:	xbrli:monetaryItemType
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Period Type:	instant

The assets recognized for each amount of assets recorded in a transaction with the acquiree that is recognized separately from the acquisition of assets and assumptions of liabilities in the business combination.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
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-Subparagraph (e)(3)
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Period Type:	instant

Remaining amortization period of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

No definition available.

Name:	us-gaap_FiniteLivedIntangibleAssetsRemainingAmortizationPeriod1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 50
-Paragraph 1
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