| Document and Entity Information | Oct. 19, 2020 |
| Cover [Abstract] | |
| Security 12b Title | Common Stock, $0.001 par value per share |
| Trading Symbol | GTX* |
| Security Exchange Name | NYSEArca |
| Amendment Flag | false |
| Entity Central Index Key | 0001735707 |
| Document Type | 8-K |
| Document Period End Date | Oct. 19, 2020 |
| Entity Registrant Name | GARRETT MOTION INC. |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 1-38636 |
| Entity Tax Identification Number | 82-4873189 |
| Entity Address, Address Line One | La Pièce 16 |
| Entity Address, City or Town | Rolle |
| Entity Address, Country | CH |
| Entity Address, Postal Zip Code | 1180 |
| City Area Code | 41 21 |
| Local Phone Number | 695 30 00 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
