v3.10.0.1
Document and Entity Information - shares
6 Months Ended
Jun. 30, 2018
Jul. 13, 2018
Document Information [Line Items]    
Entity Registrant Name United Continental Holdings, Inc.  
Entity Central Index Key 0000100517  
Current Fiscal Year End Date --12-31  
Entity Filer Category Large Accelerated Filer  
Document Type 10-Q  
Document Period End Date Jun. 30, 2018  
Document Fiscal Year Focus 2018  
Document Fiscal Period Focus Q2  
Amendment Flag false  
Trading Symbol UAL  
Entity Common Stock, Shares Outstanding   272,603,972
United Airlines, Inc.    
Document Information [Line Items]    
Entity Registrant Name United Airlines, Inc.  
Entity Central Index Key 0000319687  
Current Fiscal Year End Date --12-31  
Entity Filer Category Non-accelerated Filer  
Entity Common Stock, Shares Outstanding   1,000