Document and Entity Information (USD $)
In Billions, except Share data, unless otherwise specified
3 Months Ended
Mar. 31, 2011
May 02, 2011
Jun. 30, 2010
Document and Entity Information [Abstract]      
Entity Registrant Name NATIONAL OILWELL VARCO INC    
Entity Central Index Key 0001021860    
Document Type 10-Q    
Document Period End Date Mar. 31, 2011    
Amendment Flag false    
Document Fiscal Year Focus 2011    
Document Fiscal Period Focus Q1    
Current Fiscal Year End Date --12-31    
Entity Well-known Seasoned Issuer Yes    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Filer Category Large Accelerated Filer    
Entity Public Float     $ 13.9
Entity Common Stock, Shares Outstanding   423,077,225