SEGMENT INFORMATION - Segment Financial Information (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Segment Reporting Information [Line Items]
Total sales	$ 1,927	$ 1,830
Income (loss) from operations	239	192
Interest expense and other, net	(39)	(34)
Income (loss) before income taxes	200	158
Freight Segment
Segment Reporting Information [Line Items]
Total sales	1,322	1,183
Transit Segment
Segment Reporting Information [Line Items]
Total sales	605	647
Operating Segments | Freight Segment
Segment Reporting Information [Line Items]
Total sales	1,335	1,195
Income (loss) from operations	189	142
Interest expense and other, net	0	0
Income (loss) before income taxes	189	142
Operating Segments | Transit Segment
Segment Reporting Information [Line Items]
Total sales	613	657
Income (loss) from operations	65	70
Interest expense and other, net	0	0
Income (loss) before income taxes	65	70
Corporate Activities and Elimination
Segment Reporting Information [Line Items]
Total sales	(21)	(22)
Income (loss) from operations	(15)	(20)
Interest expense and other, net	(39)	(34)
Income (loss) before income taxes	(54)	(54)
Corporate Activities and Elimination | Freight Segment
Segment Reporting Information [Line Items]
Total sales	13	12
Corporate Activities and Elimination | Transit Segment
Segment Reporting Information [Line Items]
Total sales	$ 8	$ 10