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Basis of Presentation - Additional Information (Details) shares in Millions			9 Months Ended
	Oct. 01, 2018 shares	Sep. 12, 2018 USD ($)	Sep. 30, 2019
Indemnification and Reimbursement Agreement
Basis Of Presentation [Line Items]
Agreement termination date		Dec. 31, 2048
Agreement termination description		The Indemnification and Reimbursement Agreement provides that the agreement will terminate upon the earlier of (x) December 31, 2048 or (y) December 31st of the third consecutive year during which certain amounts owed to Honeywell during each such year were less than $25 million as converted into Euros in accordance with the terms of the agreement.	The Indemnification and Reimbursement Agreement provides that the agreement will terminate upon the earlier of (x) December 31, 2048 or (y) December 31st of the third consecutive year during which certain amounts owed to Honeywell during each such year were less than $25 million as converted into Euros in accordance with the terms of the agreement.
Bendix
Basis Of Presentation [Line Items]
Percentage of asbestos and environmental liabilities liable to pay		100.00%	100.00%
Honeywell
Basis Of Presentation [Line Items]
Conversion common stock shareowner received ratio	0.1
Description of conversion common stock shareowner received ratio	Each Honeywell stockholder of record received one share of Garrett common stock for every 10 shares of Honeywell common stock held on the record date.
Shares of Garrett common stock distributed \| shares	74
Honeywell \| Indemnification and Reimbursement Agreement
Basis Of Presentation [Line Items]
Percentage of net insurance receipts		90.00%
Honeywell \| Indemnification and Reimbursement Agreement \| Maximum
Basis Of Presentation [Line Items]
Liability for asbestos and environmental claims maximum amount converted into euros \| $		$ 25,000,000
Honeywell \| Bendix \| Indemnification and Reimbursement Agreement
Basis Of Presentation [Line Items]
Percentage of asbestos and environmental liabilities liable to pay		90.00%
Garrett Motion Inc. \| Honeywell
Basis Of Presentation [Line Items]
Pro rata distribution of outstanding shares, percentage	100.00%