RESTRUCTURING (Details) - Integration 2.0 $ in Millions	3 Months Ended
	Mar. 31, 2023 USD ($)	Mar. 31, 2022 USD ($)	Dec. 31, 2021 USD ($) facility employee
Restructuring Cost and Reserve [Line Items]
Restructuring period		3 years
Restructuring charges	$ 9	$ 0	$ 78
Number of facilities to be closed | facility			15
Number of positions eliminated | employee			1,100
Transit Segment
Restructuring Cost and Reserve [Line Items]
Restructuring charges	7
Freight Segment
Restructuring Cost and Reserve [Line Items]
Restructuring charges	2
Cost of Goods Sold
Restructuring Cost and Reserve [Line Items]
Restructuring charges	4
Selling, General and Administrative Expenses
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 5
Minimum
Restructuring Cost and Reserve [Line Items]
Total expected costs		135
Maximum
Restructuring Cost and Reserve [Line Items]
Total expected costs		$ 165