XML 74 R42.htm IDEA: XBRL DOCUMENT v3.20.1

Segments - Additional Information (Detail) $ in Millions	3 Months Ended
	Mar. 31, 2020 USD ($) Segment	Mar. 31, 2019 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | Segment	3
Charges/ (reversals)	$ 2,023	$ 11
Goodwill, Indefinite-lived and Finite-Lived Intangible and Long-Lived Tangible Assets [Member]
Segment Reporting Information [Line Items]
Charges/ (reversals)	1,891
Inventory Charges [Member]
Segment Reporting Information [Line Items]
Charges/ (reversals)	114	11
Severance, Facility Closures And Other Items [Member]
Segment Reporting Information [Line Items]
Charges/ (reversals)	$ 18	$ 11

X

- Definition

Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

+ References

No definition available.

+ Details

Name:	us-gaap_NumberOfReportableSegments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 5.P.3)
-URI http://asc.fasb.org/extlink&oid=115931487&loc=d3e140864-122747

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6394359&loc=d3e17939-110869

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3602-108585

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 5.P.4(b))
-URI http://asc.fasb.org/extlink&oid=115931487&loc=d3e140904-122747

+ Details

Name:	us-gaap_RestructuringCharges
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

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.

+ References

No definition available.

+ Details

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

X

- Details

Name:	us-gaap_RestructuringCostAndReserveAxis=nov_GoodwillIndefiniteLivedAndFiniteLivedIntangibleAndLongLivedTangibleAssetsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_RestructuringCostAndReserveAxis=nov_InventoryChargesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_RestructuringCostAndReserveAxis=nov_SeveranceFacilityClosuresAndOtherItemsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: