Revenue Recognition - Disaggregation of Revenue by Operating Segment and Major Typles of Products or Services (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Disaggregation of Revenue [Line Items]
Sales	$ 1,657.2	$ 1,651.2	$ 3,299.5	$ 3,237.8
Products
Disaggregation of Revenue [Line Items]
Sales	1,112.0		2,238.0
Solutions & Services
Disaggregation of Revenue [Line Items]
Sales	545.2		1,061.5
Architecture & Software
Disaggregation of Revenue [Line Items]
Sales	739.7		1,492.8
Architecture & Software | Products
Disaggregation of Revenue [Line Items]
Sales	739.7		1,492.8
Architecture & Software | Solutions & Services
Disaggregation of Revenue [Line Items]
Sales	0.0		0.0
Control Products & Solutions
Disaggregation of Revenue [Line Items]
Sales	917.5		1,806.7
Control Products & Solutions | Products
Disaggregation of Revenue [Line Items]
Sales	372.3		745.2
Control Products & Solutions | Solutions & Services
Disaggregation of Revenue [Line Items]
Sales	$ 545.2		$ 1,061.5