EARNINGS PER SHARE - Computation of Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Numerator
Net income attributable to Wabtec common shareholders - basic	$ 556	$ 413	$ 325
Add: dividends declared - preferred shares	0	0	1
Net income attributable to Wabtec common shareholders - diluted	$ 556	$ 413	$ 326
Denominator
Basic weighted average shares outstanding (in shares)	187.7	189.9	170.5
Assumed conversion of preferred shares (in shares)	0.0	0.0	6.4
Assumed conversion of dilutive stock-based compensation plans (in shares)	0.4	0.5	0.4
Weighted average shares outstanding - diluted (in shares)	188.1	190.4	177.3
Net income per common share attributable to Wabtec shareholders
Basic (in dollars per share)	$ 2.96	$ 2.18	$ 1.91
Diluted (in dollars per share)	$ 2.96	$ 2.17	$ 1.84