XML 80 R64.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Employee Benefit Plans - Assumption Rates Used for Benefit Obligations (Detail) | 12 Months Ended
--- | ---
Dec. 31, 2018 | Dec. 31, 2017
United States [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Discount rate minimum | 3.90% | 3.00%
Discount rate maximum | 4.20% | 3.60%
Foreign Plan [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Discount rate minimum | 1.80% | 1.80%
Discount rate maximum | 2.90% | 2.40%
Salary increase minimum | 1.80% | 1.80%
Salary increase maximum | 3.40% | 3.30%

X
- Definition Defined benefit plan assumptions used calculating benefit obligation discount rate maximum. + References No definition available. + Details
Name: | nov_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRateMaximum
Namespace Prefix: | nov_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Defined benefit plan assumptions used calculating benefit obligation discount rate minimum. + References No definition available. + Details
Name: | nov_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRateMinimum
Namespace Prefix: | nov_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Defined benefit plan assumptions used calculating benefit obligation rate of compensation increase maximum. + References No definition available. + Details
Name: | nov_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncreaseMaximum
Namespace Prefix: | nov_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Defined benefit plan assumptions used calculating benefit obligation rate of compensation increase minimum. + References No definition available. + Details
Name: | nov_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncreaseMinimum
Namespace Prefix: | nov_
Data Type: | num:percentItemType
Balance Type: | na
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_DefinedBenefitPlanDisclosureLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_RetirementPlanSponsorLocationAxis=country_US
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RetirementPlanSponsorLocationAxis=us-gaap_ForeignPlanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |