Document and Entity Information Document
9 Months Ended
Sep. 30, 2018
Document and Entity Information  
Entity Registrant Name CATERPILLAR INC
Entity Central Index Key 0000018230
Document Type 10-Q
Document Period End Date Sep. 30, 2018
Amendment Flag false
Entity Emerging Growth Company false
Entity Small Business false
Current Fiscal Year End Date --12-31
Entity Current Reporting Status Yes
Entity Filer Category Large Accelerated Filer
Entity Common Stock, Shares Outstanding 590,106,711
Document Fiscal Year Focus 2018
Document Fiscal Period Focus Q3