Document and Entity Information - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2016
Feb. 15, 2017
Jun. 30, 2016
Document and Entity Information [Abstract]      
Document Type 10-K    
Document Period End Date Dec. 31, 2016    
Document Fiscal Period Focus Q4    
Document Fiscal Year Focus 2016    
Amendment Flag false    
Entity Registrant Name Marathon Oil Corp    
Entity Central Index Key 0000101778    
Entity Current Reporting Status Yes    
Entity Voluntary Filers No    
Current Fiscal Year End Date --12-31    
Entity Filer Category Large Accelerated Filer    
Entity Well Known Seasoned Issuer Yes    
Entity Common Stock, Shares Outstanding   847,201,196  
Entity Public Float     $ 12,696