Guarantor Subsidiaries Financial Information - Balance Sheet (Details) - USD ($) $ in Millions	Sep. 30, 2019	Jun. 30, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2017
Condensed Financial Statements, Captions [Line Items]
Preferred stock, outstanding (in shares)	0		0
Cash and cash equivalents	$ 587.4		$ 2,342.3	$ 2,135.4		$ 233.4
Receivables, net	1,673.3		1,146.8
Inventories	1,957.3		844.9
Current assets - other	192.4		115.6
Total current assets	4,410.4		4,449.6
Property, plant and equipment, net	1,622.7		563.8
Goodwill	8,103.2		2,396.5
Investment in subsidiaries	0.0		0.0
Other intangibles, net	4,207.0		1,129.9
Other long-term assets	557.6		109.4
Total Assets	18,900.9		8,649.2
Current liabilities	3,198.9		1,646.6
Inter-company	0.0		0.0
Long-term debt	4,633.5		3,792.8
Long-term liabilities - other	1,339.1		340.7
Total Liabilities	9,171.5		5,780.1
Shareholders' equity	9,696.4		2,865.2
Noncontrolling interest	33.0		3.9
Total Equity	9,729.4	$ 9,835.2	2,869.1	2,910.4	$ 2,874.6	2,828.5
Total Liabilities and Equity	18,900.9		8,649.2
Elimination
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	0.0		0.0	0.0		0.0
Receivables, net	0.0		0.0
Inventories	0.0		0.0
Current assets - other	0.0		0.0
Total current assets	0.0		0.0
Property, plant and equipment, net	0.0		0.0
Goodwill	0.0		0.0
Investment in subsidiaries	(22,974.1)		(10,730.1)
Other intangibles, net	0.0		0.0
Other long-term assets	0.0		0.0
Total Assets	(22,974.1)		(10,730.1)
Current liabilities	0.0		0.0
Inter-company	0.0		0.0
Long-term debt	0.0		0.0
Long-term liabilities - other	0.0		0.0
Total Liabilities	0.0		0.0
Shareholders' equity	(22,974.1)		(10,730.1)
Noncontrolling interest	0.0		0.0
Total Equity	(22,974.1)		(10,730.1)
Total Liabilities and Equity	(22,974.1)		(10,730.1)
Parent | Reportable Legal Entities
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	9.8		1,782.6	1,760.8		0.9
Receivables, net	134.9		106.8
Inventories	143.2		149.7
Current assets - other	18.0		11.9
Total current assets	305.9		2,051.0
Property, plant and equipment, net	65.5		51.6
Goodwill	512.1		25.3
Investment in subsidiaries	16,823.1		6,708.0
Other intangibles, net	37.3		29.3
Other long-term assets	47.8		8.8
Total Assets	17,791.7		8,874.0
Current liabilities	424.0		264.5
Inter-company	2,838.8		1,947.5
Long-term debt	4,422.3		3,779.7
Long-term liabilities - other	410.2		17.1
Total Liabilities	8,095.3		6,008.8
Shareholders' equity	9,681.4		2,865.2
Noncontrolling interest	15.0		0.0
Total Equity	9,696.4		2,865.2
Total Liabilities and Equity	17,791.7		8,874.0
Guarantors | Reportable Legal Entities
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	110.0		(0.1)	0.1		0.7
Receivables, net	235.2		61.5
Inventories	751.0		69.1
Current assets - other	24.7		0.7
Total current assets	1,120.9		131.2
Property, plant and equipment, net	44.5		24.8
Goodwill	283.2		283.2
Investment in subsidiaries	6,151.0		4,022.1
Other intangibles, net	76.7		78.5
Other long-term assets	162.3		0.1
Total Assets	7,838.6		4,539.9
Current liabilities	1,107.4		91.0
Inter-company	(2,170.4)		(1,436.2)
Long-term debt	0.0		0.0
Long-term liabilities - other	174.8		48.6
Total Liabilities	(888.2)		(1,296.6)
Shareholders' equity	8,726.8		5,836.5
Noncontrolling interest	0.0		0.0
Total Equity	8,726.8		5,836.5
Total Liabilities and Equity	7,838.6		4,539.9
Non-Guarantors | Reportable Legal Entities
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	467.6		559.8	$ 374.5		$ 231.8
Receivables, net	1,303.2		978.5
Inventories	1,063.1		626.1
Current assets - other	149.7		103.0
Total current assets	2,983.6		2,267.4
Property, plant and equipment, net	1,512.7		487.4
Goodwill	7,307.9		2,088.0
Investment in subsidiaries	0.0		0.0
Other intangibles, net	4,093.0		1,022.1
Other long-term assets	347.5		100.5
Total Assets	16,244.7		5,965.4
Current liabilities	1,667.5		1,291.1
Inter-company	(668.4)		(511.3)
Long-term debt	211.2		13.1
Long-term liabilities - other	754.1		275.0
Total Liabilities	1,964.4		1,067.9
Shareholders' equity	14,262.3		4,893.6
Noncontrolling interest	18.0		3.9
Total Equity	14,280.3		4,897.5
Total Liabilities and Equity	$ 16,244.7		$ 5,965.4
Series A Preferred Stock | Wabtec
Condensed Financial Statements, Captions [Line Items]
Preferred stock, outstanding (in shares)	15,000