Earnings Per Share - Computation of Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Earnings Per Share Numerator Activity [Abstract]
Net income attributable to Wabtec shareholders	$ 124.8	$ 86.8	$ 237.2	$ 198.4
Less: dividends declared - common shares and non-vested restricted stock	(22.5)	(22.8)	(45.4)	(45.8)
Undistributed earnings	$ 102.3	$ 64.0	$ 191.8	$ 152.6
Percentage allocated to common shareholders	99.80%	99.70%	99.70%	99.70%
Undistributed earnings allocated to common shareholders	$ 102.1	$ 63.8	$ 191.2	$ 152.1
Add: dividends declared - common shares	22.4	22.8	45.3	45.7
Numerator for basic earnings per common share	124.5	86.6	236.5	197.8
Numerator for diluted earnings per common share	$ 124.5	$ 86.6	$ 236.5	$ 197.8
Denominator
Basic weighted average common shares outstanding (in shares)	188.6	189.8	188.5	190.3
Assumed conversion of dilutive stock-based compensation plans (in shares)	0.3	0.4	0.4	0.5
Denominator for diluted earnings per common share adjusted weighted average shares and assumed conversion (in shares)	188.9	190.2	188.9	190.8
Net income attributable to Wabtec shareholders per common share
Basic (in dollars per share)	$ 0.66	$ 0.46	$ 1.25	$ 1.04
Diluted (in dollars per share)	$ 0.66	$ 0.46	$ 1.25	$ 1.04
Basic weighted-average common shares outstanding and non-vested restricted stock expected to vest (in shares)	189.0	190.3	189.0	190.8