SEGMENT INFORMATION - Sales by Product (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Segment Reporting Information [Line Items]
Total sales	$ 1,927	$ 1,830
Freight Segment
Segment Reporting Information [Line Items]
Total sales	1,322	1,183
Transit Segment
Segment Reporting Information [Line Items]
Total sales	605	647
Equipment | Freight Segment
Segment Reporting Information [Line Items]
Total sales	274	262
Components | Freight Segment
Segment Reporting Information [Line Items]
Total sales	229	203
Digital Electronics | Freight Segment
Segment Reporting Information [Line Items]
Total sales	153	156
Services
Segment Reporting Information [Line Items]
Total sales	422	345
Services | Freight Segment
Segment Reporting Information [Line Items]
Total sales	666	562
Original Equipment Manufacturer | Transit Segment
Segment Reporting Information [Line Items]
Total sales	292	287
Aftermarket | Transit Segment
Segment Reporting Information [Line Items]
Total sales	$ 313	$ 360