Commitments and Contingencies - Additional Information (Details)				3 Months Ended			12 Months Ended
	Dec. 18, 2020 USD ($)	Oct. 01, 2018 USD ($) Installment	Sep. 12, 2018 USD ($)	Mar. 31, 2021 USD ($) $ / shares	Mar. 31, 2020 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2022 USD ($)	Jan. 11, 2021 USD ($)	Sep. 30, 2020 USD ($)
Loss Contingencies [Line Items]
Make-whole premium claim amount				$ 0					$ 15,000,000
Brazilian Tax Authorities
Loss Contingencies [Line Items]
Estimated amount of contingency including penalties and interest				27,000,000
Right to offset federal tax				$ 27,000,000
Debtors
Loss Contingencies [Line Items]
Common stock exchange rate for cancellation per share | $ / shares				$ 6.25
Honeywell Indemnity Agreement
Loss Contingencies [Line Items]
Loss contingency payable			$ 175,000,000
Minimum amount agreed to maintain for termination			25,000,000
Agreement termination description				The Honeywell Indemnity 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.
Indemnification and Reimbursement Agreement
Loss Contingencies [Line Items]
Minimum amount agreed to maintain for termination			$ 25,000,000
Agreement termination description				The Honeywell Indemnity 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.
Honeywell International Inc | PSA and The Transaction, The Amended Plan
Loss Contingencies [Line Items]
Litigation cash payment at emergence				$ 375,000,000
Option for partial payment period at emergence				18 months
Honeywell International Inc | PSA and The Transaction, The Amended Plan | Series B Preferred Stock
Loss Contingencies [Line Items]
Preferred stock issued payable annually in 2023				$ 100,000,000
Preferred stock issued payable annually in 2024				100,000,000
Preferred stock issued payable annually in 2025				100,000,000
Preferred stock issued payable annually in 2026				100,000,000
Preferred stock issued payable annually in 2027				100,000,000
Preferred stock issued payable annually in 2028				100,000,000
Preferred stock issued payable annually in 2029				100,000,000
Preferred stock issued payable annually in 2030				100,000,000
Option to prepay preferred stock at call price				$ 584,000,000
Discount rate				7.25%
Option for partial payment of preferred stock reducing present value				$ 400,000,000
Honeywell International Inc | PSA and The Transaction, The Amended Plan | Series B Preferred Stock | Scenario Forecast
Loss Contingencies [Line Items]
Preferred stock issued payable in instalments								$ 35,000,000
Honeywell International Inc | Tax Matters Agreement
Loss Contingencies [Line Items]
Obligation payment connection with mandatory transition tax claim		$ 240,000,000								$ 273,000,000
Number of annual installments | Installment		5
Mandatory transition tax rate first installment		8.00%
Mandatory transition tax rate second installment		8.00%
Mandatory transition tax rate third installment		15.00%
Mandatory transition tax rate fourth installment		20.00%
Mandatory transition tax rate fifth installment		25.00%
Payments related Tax Matters Agreement						$ 19,000,000	$ 18,000,000
Honeywell International Inc | Minimum [Member]
Loss Contingencies [Line Items]
Loss contingency, owes	$ 1,900,000,000
Honeywell International Inc | Honeywell Indemnity Agreement
Loss Contingencies [Line Items]
Percentage of net insurance receipts			90.00%
Payment made in connection with the Indemnification and Reimbursement Agreement					$ 35,000,000
Description of indemnification agreement				As of the Spin-Off date of October 1, 2018, Garrett ASASCO is obligated to make payments to Honeywell in amounts equal to 90% of certain Honeywell asbestos-related liability payments and accounts payable, primarily related to the Bendix business in the United States, as well as certain environmental-related liability payments and accounts payable and non-United States asbestos-related liability payments and accounts payable, in each case related to legacy elements of the Business, including the legal costs of defending and resolving such liabilities, less 90% of Honeywell’s net insurance receipts and, as may be applicable, certain other recoveries associated with such liabilities. Pursuant to the terms of this Honeywell Indemnity Agreement, Garrett ASASCO is responsible for paying to Honeywell such amounts, up to a cap of an amount equal to the Euro-to-U.S. dollar exchange rate determined by Honeywell as of a date within two business days prior to the date of the Distribution (1.16977 USD = 1 EUR) equivalent of $175 million in respect of such liabilities arising in any given calendar year.
Honeywell International Inc | Indemnification and Reimbursement Agreement
Loss Contingencies [Line Items]
Percentage of net insurance receipts			90.00%
Bendix | Honeywell International Inc | Honeywell Indemnity Agreement
Loss Contingencies [Line Items]
Percentage of asbestos and environmental liabilities liable to pay			90.00%
Bendix | Honeywell International Inc | Indemnification and Reimbursement Agreement
Loss Contingencies [Line Items]
Percentage of asbestos and environmental liabilities liable to pay			90.00%