Guarantor Subsidiaries Financial Information - Income Statement (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Condensed Financial Statements, Captions [Line Items]
Total net sales	$ 2,001.7	$ 1,077.8	$ 5,831.6	$ 3,245.7
Total cost of sales	(1,402.3)	(775.8)	(4,228.5)	(2,308.8)
Gross profit	599.4	302.0	1,603.1	936.9
Total operating expenses	(430.3)	(176.8)	(1,166.1)	(556.9)
Income from operations	169.1	125.2	437.0	380.0
Interest expense, net	(57.7)	(23.7)	(160.8)	(75.9)
Other income (expense), net	1.9	1.2	(4.1)	6.0
Equity earnings (loss)	0.0	0.0	0.0	0.0
Income from operations before income taxes	113.3	102.7	272.1	310.1
Income tax benefit (expense)	(22.7)	(16.6)	(82.6)	(53.2)
Net income	90.6	86.1	189.5	256.9
Less: Net loss attributable to noncontrolling interest	0.5	1.6	1.5	3.7
Net income attributable to Wabtec shareholders	91.1	87.7	191.0	260.6
Comprehensive income attributable to Wabtec shareholders	(88.3)	38.2	(21.0)	99.9
Elimination
Condensed Financial Statements, Captions [Line Items]
Total net sales	(451.9)	(60.4)	(994.3)	(178.9)
Total cost of sales	362.0	34.2	775.3	105.1
Gross profit	(89.9)	(26.2)	(219.0)	(73.8)
Total operating expenses	0.0	0.0	0.0	0.0
Income from operations	(89.9)	(26.2)	(219.0)	(73.8)
Interest expense, net	0.0	0.0	0.0	0.0
Other income (expense), net	0.0	0.0	0.0	0.0
Equity earnings (loss)	(141.9)	(188.9)	(582.9)	(635.2)
Income from operations before income taxes	(231.8)	(215.1)	(801.9)	(709.0)
Income tax benefit (expense)	0.0	0.0	0.0	0.0
Net income	(231.8)	(215.1)	(801.9)	(709.0)
Less: Net loss attributable to noncontrolling interest	0.0	0.0	0.0	0.0
Net income attributable to Wabtec shareholders	(231.8)	(215.1)	(801.9)	(709.0)
Comprehensive income attributable to Wabtec shareholders	(231.8)	(215.1)	(801.9)	(709.0)
Parent | Reportable Legal Entities
Condensed Financial Statements, Captions [Line Items]
Total net sales	174.3	169.4	553.1	499.2
Total cost of sales	(126.6)	(122.9)	(428.5)	(364.5)
Gross profit	47.7	46.5	124.6	134.7
Total operating expenses	(70.9)	(37.1)	(235.9)	(122.5)
Income from operations	(23.2)	9.4	(111.3)	12.2
Interest expense, net	(58.8)	(23.0)	(159.8)	(75.1)
Other income (expense), net	23.0	(1.5)	44.6	7.7
Equity earnings (loss)	125.1	97.1	402.4	331.0
Income from operations before income taxes	66.1	82.0	175.9	275.8
Income tax benefit (expense)	24.9	5.7	14.9	(15.2)
Net income	91.0	87.7	190.8	260.6
Less: Net loss attributable to noncontrolling interest	0.0	0.0	0.0	0.0
Net income attributable to Wabtec shareholders	91.0	87.7	190.8	260.6
Comprehensive income attributable to Wabtec shareholders	91.0	87.7	190.8	261.2
Guarantors | Reportable Legal Entities
Condensed Financial Statements, Captions [Line Items]
Total net sales	900.4	118.5	2,133.9	374.6
Total cost of sales	(617.8)	(75.0)	(1,520.1)	(236.7)
Gross profit	282.6	43.5	613.8	137.9
Total operating expenses	(80.7)	(14.7)	(177.9)	(40.7)
Income from operations	201.9	28.8	435.9	97.2
Interest expense, net	3.3	3.2	9.9	9.3
Other income (expense), net	(9.3)	0.0	(16.0)	(0.7)
Equity earnings (loss)	16.8	91.8	180.5	304.2
Income from operations before income taxes	212.7	123.8	610.3	410.0
Income tax benefit (expense)	(35.3)	0.0	(77.9)	0.0
Net income	177.4	123.8	532.4	410.0
Less: Net loss attributable to noncontrolling interest	0.0	0.0	0.0	0.0
Net income attributable to Wabtec shareholders	177.4	123.8	532.4	410.0
Comprehensive income attributable to Wabtec shareholders	177.4	123.8	532.4	410.0
Non-Guarantors | Reportable Legal Entities
Condensed Financial Statements, Captions [Line Items]
Total net sales	1,378.9	850.3	4,138.9	2,550.8
Total cost of sales	(1,019.9)	(612.1)	(3,055.2)	(1,812.7)
Gross profit	359.0	238.2	1,083.7	738.1
Total operating expenses	(278.7)	(125.0)	(752.3)	(393.7)
Income from operations	80.3	113.2	331.4	344.4
Interest expense, net	(2.2)	(3.9)	(10.9)	(10.1)
Other income (expense), net	(11.8)	2.7	(32.7)	(1.0)
Equity earnings (loss)	0.0	0.0	0.0	0.0
Income from operations before income taxes	66.3	112.0	287.8	333.3
Income tax benefit (expense)	(12.3)	(22.3)	(19.6)	(38.0)
Net income	54.0	89.7	268.2	295.3
Less: Net loss attributable to noncontrolling interest	0.5	1.6	1.5	3.7
Net income attributable to Wabtec shareholders	54.5	91.3	269.7	299.0
Comprehensive income attributable to Wabtec shareholders	$ (124.9)	$ 41.8	$ 57.7	$ 137.7