v2.3.0.11
Account Receivable (Details) (USD $)
 3 Months Ended 6 Months Ended
Jun. 30, 2011
Jun. 30, 2010
Jun. 30, 2011
Jun. 30, 2010
Dec. 31, 2010
Accounts Receivable Details [Abstract]          
Allowance for doubtful accounts $ 6,000,000   $ 6,000,000   $ 5,000,000
Allowance for doubtful accounts - receivables not expected to collected in one year 49,000,000   49,000,000   51,000,000
Receivables Securitization Facility [Abstract]          
Total capacity to transfer undivided interests to investors under the receivables securitization facility 600,000,000   600,000,000   600,000,000
Value of the outstanding undivided interest held by investors under the receivables securitization facility 100,000,000   100,000,000   100,000,000
Accounts receivable supporting the undivided interest held by investors 1,100,000,000   1,100,000,000   960,000,000
Value of interest retained by Union Pacific Receivables, Inc. 1,100,000,000   1,100,000,000   960,000,000
Receivables collected by the Railroad 4,600,000,000 4,000,000,000 8,900,000,000 7,700,000,000  
Cost of the receivables securitization facility $ 1,000,000 $ 1,000,000 $ 2,000,000 $ 3,000,000