| Document and Entity Information | Oct. 21, 2021 |
| Cover [Abstract] | |
| Entity Address, Country | LU |
| Amendment Flag | false |
| Entity Central Index Key | 0001525773 |
| Document Type | 8-K |
| Document Period End Date | Oct. 21, 2021 |
| Entity Registrant Name | Intelsat S.A. |
| Entity Incorporation State Country Code | N4 |
| Entity File Number | 001-35878 |
| Entity Tax Identification Number | 98-1009418 |
| Entity Address, Address Line One | 4 rue Albert Borschette |
| Entity Address, City or Town | Luxembourg |
| Entity Address, Postal Zip Code | L-1246 |
| City Area Code | +352 27 |
| Local Phone Number | 84-1600 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
