v2.3.0.11
Document and Entity Information (USD $)
In Millions, except Share data
6 Months Ended
Jun. 30, 2011
Jul. 15, 2011
Jun. 30, 2010
Document and Entity Information [Abstract]      
Document type 10-Q    
Document period end date Jun. 30, 2011
Amendment flag false    
Entity registrant name UNION PACIFIC CORPORATION    
Entity central index key 0000100885    
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   488,088,696  
Entity public float     $ 34,575
Document fiscal year focus 2011    
Document fiscal period focus Q2