XML 80 R64.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Employee Benefit Plans - Additional Information (Detail) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2017 USD ($) Employees | Dec. 31, 2016 USD ($) | Dec. 31, 2015 USD ($)
Compensation Related Costs Disclosure [Line Items] |  |  |
Expenses for defined-contribution plans | $ 64 | $ 66 | $ 95
Net periodic benefit cost | 1 | $ 5 | $ 5
Defined benefit plan, expected future benefit payments in year five | $ 33 |  |
Expected years of defined benefit plans | 5 years |  |
Expected future benefit amounts to pay, total | $ 324 |  |
United States [Member] |  |  |
Compensation Related Costs Disclosure [Line Items] |  |  |
Number of U.S retirees and spouses participate in defined benefit health care plans | Employees | 1,950 |  |
Number of U.S. employees participate in defined benefit health care plans | Employees | 40 |  |

X
- Definition Compensation Related Costs Disclosure [Line Items] + References No definition available. + Details
Name: | nov_CompensationRelatedCostsDisclosureLineItems
Namespace Prefix: | nov_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Defined Benefit Plan Estimated Future Employer Contributions. + References No definition available. + Details
Name: | nov_DefinedBenefitPlanEstimatedFutureEmployerContributions
Namespace Prefix: | nov_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Defined benefit plan number of United States employees participate in defined benefit health care plans. + References No definition available. + Details
Name: | nov_DefinedBenefitPlanNumberOfEmployeesParticipateInDefinedBenefitHealthCarePlans
Namespace Prefix: | nov_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of retirees and spouses participate in defined benefit health care plans. + References No definition available. + Details
Name: | nov_DefinedBenefitPlanNumberOfRetireesAndSpousesParticipateInDefinedBenefitHealthCarePlans
Namespace Prefix: | nov_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Expected years of Defined Benefit Plans. + References No definition available. + Details
Name: | nov_ExpectedTermOfDefinedBenefitPlans
Namespace Prefix: | nov_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of benefits for defined benefit plan expected to be paid in fifth fiscal year following latest fiscal year. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (f) -URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of net periodic benefit cost (credit) for defined benefit plan. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (h) -URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of cost for defined contribution plan. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 70 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=49170846&loc=d3e28014-114942 + Details
Name: | us-gaap_DefinedContributionPlanCostRecognized
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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