v3.19.1
Document and Entity Information - shares
3 Months Ended
Mar. 31, 2019
Apr. 30, 2019
Document and Entity Information [Abstract]    
Document Type 10-Q  
Amendment Flag false  
Document Period End Date Mar. 31, 2019  
Document Fiscal Year Focus 2019  
Document Fiscal Period Focus Q1  
Trading Symbol MAR  
Entity Registrant Name MARRIOTT INTERNATIONAL INC /MD/  
Entity Central Index Key 0001048286  
Current Fiscal Year End Date --12-31  
Entity Filer Category Large Accelerated Filer  
Entity Emerging Growth Company false  
Entity Small Business false  
Entity Common Stock, Shares Outstanding   332,988,834