Revenue Recognition - Disaggregation of Revenue by Operating Segment and Major Types of Products or Services (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Mar. 31, 2019
Disaggregation of Revenue [Line Items]
Sales	$ 1,681.3	$ 1,657.2	$ 3,365.8	$ 3,299.5
Products
Disaggregation of Revenue [Line Items]
Sales	1,136.1	1,112.0	2,276.4	2,238.0
Solutions & Services
Disaggregation of Revenue [Line Items]
Sales	545.2	545.2	1,089.4	1,061.5
Architecture & Software
Disaggregation of Revenue [Line Items]
Sales	757.1	739.7	1,508.7	1,492.8
Architecture & Software | Products
Disaggregation of Revenue [Line Items]
Sales	757.1	739.7	1,508.7	1,492.8
Architecture & Software | Solutions & Services
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0	0.0	0.0
Control Products & Solutions
Disaggregation of Revenue [Line Items]
Sales	924.2	917.5	1,857.1	1,806.7
Control Products & Solutions | Products
Disaggregation of Revenue [Line Items]
Sales	379.0	372.3	767.7	745.2
Control Products & Solutions | Solutions & Services
Disaggregation of Revenue [Line Items]
Sales	$ 545.2	$ 545.2	$ 1,089.4	$ 1,061.5