Revenue Recognition - Disaggregation of Revenue by Operating Segment and by Geographic Region (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Disaggregation of Revenue [Line Items]
Sales	$ 1,730.2	$ 1,665.1	$ 1,657.2	$ 1,642.3	$ 1,729.5	$ 1,698.7	$ 1,651.2	$ 1,586.6	$ 6,694.8	$ 6,666.0	$ 6,311.3
North America
Disaggregation of Revenue [Line Items]
Sales									4,014.3	3,964.1	3,801.8
Europe, Middle East and Africa
Disaggregation of Revenue [Line Items]
Sales									1,249.8	1,286.8	1,193.7
Asia Pacific
Disaggregation of Revenue [Line Items]
Sales									908.6	933.3	866.4
Latin America
Disaggregation of Revenue [Line Items]
Sales									522.1	$ 481.8	$ 449.4
Architecture & Software
Disaggregation of Revenue [Line Items]
Sales									3,021.9
Architecture & Software | North America
Disaggregation of Revenue [Line Items]
Sales									1,752.1
Architecture & Software | Europe, Middle East and Africa
Disaggregation of Revenue [Line Items]
Sales									654.2
Architecture & Software | Asia Pacific
Disaggregation of Revenue [Line Items]
Sales									426.4
Architecture & Software | Latin America
Disaggregation of Revenue [Line Items]
Sales									189.2
Control Products & Solutions
Disaggregation of Revenue [Line Items]
Sales									3,672.9
Control Products & Solutions | North America
Disaggregation of Revenue [Line Items]
Sales									2,262.2
Control Products & Solutions | Europe, Middle East and Africa
Disaggregation of Revenue [Line Items]
Sales									595.6
Control Products & Solutions | Asia Pacific
Disaggregation of Revenue [Line Items]
Sales									482.2
Control Products & Solutions | Latin America
Disaggregation of Revenue [Line Items]
Sales									$ 332.9