Spin-off of Distribution Business - Additional Information (Detail) - Now Inc [Member] $ in Millions		3 Months Ended	6 Months Ended
May. 22, 2014	Jun. 30, 2014 USD ($)	Jun. 30, 2014 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Ratio of common stock sharing	4
Sales prior to the spin-off		$ 91	$ 231
Purchases prior to the spin-off		$ 32	$ 82

For a disposal group that is a component of the entity (discontinued operation), in the period in which the operations are initially classified as discontinued, the amounts of intercompany revenue that were previously eliminated in consolidation for periods before the disposal transaction (in situations where revenue and cost producing activities with the disposed component will continue after disposal).

No definition available.

Name:	nov_DiscontinuedOperationIntercompanyAmountsWithDiscontinuedOperationBeforeDisposalTransactionRevenue1
Namespace Prefix:	nov_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration