Document and Entity Information - shares
3 Months Ended
Mar. 31, 2018
Apr. 13, 2018
Document And Entity Information [Abstract]    
Entity Registrant Name GENERAL MOTORS COMPANY  
Entity Central Index Key 0001467858  
Current Fiscal Year End Date --12-31  
Entity Filer Category Large Accelerated Filer  
Document Type 10-Q  
Document Period End Date Mar. 31, 2018  
Document Fiscal Year Focus 2018  
Document Fiscal Period Focus Q1  
Amendment Flag false  
Entity Common Stock, Shares Outstanding   1,409,232,569
Entity Current Reporting Status Yes