| Cover Page | Apr. 13, 2020 |
| Entity Information [Line Items] | |
| Document Type | 8-K |
| Document Period End Date | Apr. 13, 2020 |
| Entity Registrant Name | MARRIOTT INTERNATIONAL INC /MD/ |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 1-13881 |
| Entity Tax Identification Number | 52-2055918 |
| Entity Address, Address Line One | 10400 Fernwood Road, |
| Entity Address, City or Town | Bethesda, |
| Entity Address, State or Province | MD |
| Entity Address, Postal Zip Code | 20817 |
| City Area Code | 301 |
| Local Phone Number | 380-3000 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Amendment Flag | false |
| Entity Central Index Key | 0001048286 |
| Nasdaq Global Select Market | |
| Entity Information [Line Items] | |
| Title of 12(b) Security | Class A Common Stock, $0.01 par value |
| Trading Symbol | MAR |
| Security Exchange Name | NASDAQ |
| Chicago Stock Exchange | |
| Entity Information [Line Items] | |
| Title of 12(b) Security | Class A Common Stock, $0.01 par value |
| Trading Symbol | MAR |
| Security Exchange Name | CHX |
