Equity - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions				3 Months Ended	12 Months Ended
	Jan. 31, 2025	Jun. 06, 2023	Apr. 12, 2023	Jun. 30, 2023	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 04, 2024	Feb. 13, 2024	Apr. 30, 2021
Class Of Stock [Line Items]
Stock repurchase program, authorized amount								$ 250	$ 350
Preferred Stock dividends						$ 42	$ 83
Payments for dividends of convertible preferred stock					$ 0	25	0
Stock repurchased during period (in shares)					33,493,224
Stock repurchase program, fair value assumptions, dividend yield		0.00%
Stock repurchase program, fair value assumptions, expected volatility		40.00%
Stock repurchase program, fair value assumptions, risk free interest rate		4.23%
Forward contract indexed to equity, settlement, share, fair value		$ 4
Loss on remeasurement		13			$ 0	13	0
Stock repurchased during period, value					296		6
Excise tax on share repurchases					3	8
Stock repurchased during period, transaction-related costs					$ 9
Common stock, dividends, per share, declared (in US dollar per share)					$ 0.06
Subsequent event
Class Of Stock [Line Items]
Payments of ordinary dividends, common stock	$ 12
Retained Deficit
Class Of Stock [Line Items]
Preferred Stock dividends						42	83
Stock repurchased during period, value							$ 2
Excise tax on share repurchases		$ 6				8
Centerbridge Partners, L.P. and Oaktree Capital Management, L.P. | Related Party
Class Of Stock [Line Items]
Payments for dividends of convertible preferred stock			$ 9
Series A Preferred Stock
Class Of Stock [Line Items]
Stock repurchase program, authorized amount			$ 570
Stock repurchase program, volume-weighted average share price calculation trading days		15 days	15 days
Stock repurchase program, volume-weighted average share price			$ 8.177
Shares of Garrett common stock distributed		175,337,712
Stock repurchase program, starting price (in USD per share)		$ 8.25
Stock repurchased during period, value						567
Series A Preferred Stock | Retained Deficit
Class Of Stock [Line Items]
Stock repurchased during period, value		$ 201				201
Series A Preferred Stock | Centerbridge Partners, L.P. and Oaktree Capital Management, L.P. | Related Party
Class Of Stock [Line Items]
Payments for repurchase of convertible preferred stock		$ 570
Stock repurchased during period (in shares)		69,707,719
Shares of Garrett common stock distributed			65,334,277
Series A Preferred Stock | Accumulate Dividend
Class Of Stock [Line Items]
Preferred stock, dividends per share, declared				$ 0.853509
Series A Preferred Stock | Additional Amounts
Class Of Stock [Line Items]
Preferred stock, dividends per share, declared				$ 0.144375
Preferred Stock dividends		$ 35
Payments for dividends of convertible preferred stock		25
Series A Preferred Stock | Additional Amounts | Centerbridge Partners, L.P. and Oaktree Capital Management, L.P. | Related Party
Class Of Stock [Line Items]
Payments for repurchase of convertible preferred stock		$ 10
Series A Preferred Stock | Minimum
Class Of Stock [Line Items]
Stock repurchase program (in USD per share)			$ 7.875
Series A Preferred Stock | Maximum
Class Of Stock [Line Items]
Stock repurchase program (in USD per share)			$ 8.50
Series A Preferred Stock | Centerbridge, Oaktree And Additional Investors
Class Of Stock [Line Items]
Preferred stock, shares issued (in shares)										247,757,290
Common Stock
Class Of Stock [Line Items]
Issuance of common stock for preference dividends (in shares)		25,577,517
Conversion of stock, shares issued (in shares)		175,337,712
Stock repurchased during period, value						213
Common Stock | Retained Deficit
Class Of Stock [Line Items]
Stock repurchased during period, value						$ 213
Common Stock | Centerbridge Partners, L.P. and Oaktree Capital Management, L.P. | Related Party
Class Of Stock [Line Items]
Issuance of common stock for preference dividends (in shares)			6,819,540