XML 77 R61.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Debt - Debt (Parenthetical) (Detail) - USD ($) | 12 Months Ended |
--- | --- | ---
Dec. 31, 2017 | Dec. 31, 2016 | Nov. 29, 2017
Senior Notes, Interest at 1.35% Payable Semiannually, Principal Due on December 1, 2017 [Member] |  |  |
Debt Instrument [Line Items] |  |  |
Senior note face amount | $ 500,000,000 | $ 500,000,000 |
Senior notes interest rate | 1.35% | 1.35% | 1.35%
Senior note due date | Dec. 01, 2017 | Dec. 01, 2017 |
Senior Notes, Interest at 2.60% Payable Semiannually, Principal Due on December 1, 2022 [Member] |  |  |
Debt Instrument [Line Items] |  |  |
Senior note face amount | $ 1,400,000,000 | $ 1,400,000,000 |
Senior notes interest rate | 2.60% | 2.60% |
Senior note due date | Dec. 01, 2022 | Dec. 01, 2022 |
Senior Notes, Interest at 3.95% Payable Semiannually, Principal Due on December 1, 2042 [Member] |  |  |
Debt Instrument [Line Items] |  |  |
Senior note face amount | $ 1,100,000,000 | $ 1,100,000,000 |
Senior notes interest rate | 3.95% | 3.95% |
Senior note due date | Dec. 01, 2042 | Dec. 01, 2042 |

X
- Definition Face (par) amount of debt instrument at time of issuance. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 55 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=64930739&loc=d3e28878-108400 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399 + Details
Name: | us-gaap_DebtInstrumentFaceAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Contractual interest rate for funds borrowed, under the debt agreement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(1)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

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_DebtInstrumentLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(2)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_DebtInstrumentMaturityDate
Namespace Prefix: | us-gaap_
Data Type: | xbrli:dateItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_DebtInstrumentAxis=nov_SeniorNotesDueOnDecemberOneTwoThousandSeventeenMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=nov_SeniorNotesDueOnDecemberOneTwoThousandTwentyTwoMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=nov_SeniorNotesDueOnDecemberOneTwoThousandFortyTwoMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |