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Business Segments and Geographic Areas - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Segment Reporting [Abstract]
Revenue from shipyard customer	9.00%	10.00%	12.00%

X

- Definition

Revenue from shipyard customer.

+ References

No definition available.

+ Details

Name:	nov_RevenueFromCustomer
Namespace Prefix:	nov_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

X

- Details

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