Reportable Segment Information - Sales by Geography as a Percentage of Consolidated Sales (Details) - Geographic Concentration Risk - Sales Revenue, Net	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Segment Reporting Information [Line Items]
Concentration risk	100.00%	100.00%	100.00%
North America
Segment Reporting Information [Line Items]
Concentration risk	74.00%	74.00%	75.00%
EMEA (Europe, Middle East and Africa)
Segment Reporting Information [Line Items]
Concentration risk	8.00%	7.00%	7.00%
Asia Pacific
Segment Reporting Information [Line Items]
Concentration risk	13.00%	14.00%	14.00%
Latin America
Segment Reporting Information [Line Items]
Concentration risk	5.00%	5.00%	4.00%