Revenue Recognition (Disaggregation of Revenue) (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Disaggregation of Revenue [Line Items]
Sales	$ 12,600.0	$ 12,698.6	$ 10,323.0
Operating Segments
Disaggregation of Revenue [Line Items]
Sales	$ 12,600.0	$ 12,698.6	$ 10,323.0
Percent sales by supply mode	100.00%	100.00%	100.00%
Americas | Operating Segments
Disaggregation of Revenue [Line Items]
Sales	$ 5,369.3	$ 5,368.9	$ 4,167.6
Asia | Operating Segments
Disaggregation of Revenue [Line Items]
Sales	3,216.1	3,143.3	2,920.8
Europe | Operating Segments
Disaggregation of Revenue [Line Items]
Sales	2,963.1	3,086.1	2,345.6
Middle East and India | Operating Segments
Disaggregation of Revenue [Line Items]
Sales	162.5	129.5	99.3
Corporate and other | Operating Segments
Disaggregation of Revenue [Line Items]
Sales	889.0	970.8	789.7
On-site | Operating Segments
Disaggregation of Revenue [Line Items]
Sales	$ 6,179.2	$ 6,633.1	$ 5,061.4
Percent sales by supply mode	49.00%	52.00%	49.00%
On-site | Americas | Operating Segments
Disaggregation of Revenue [Line Items]
Sales	$ 3,143.9	$ 3,423.1	$ 2,469.5
On-site | Asia | Operating Segments
Disaggregation of Revenue [Line Items]
Sales	1,923.0	1,833.9	1,718.8
On-site | Europe | Operating Segments
Disaggregation of Revenue [Line Items]
Sales	1,036.6	1,298.2	802.4
On-site | Middle East and India | Operating Segments
Disaggregation of Revenue [Line Items]
Sales	75.7	77.9	70.7
On-site | Corporate and other | Operating Segments
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0	0.0
Merchant | Operating Segments
Disaggregation of Revenue [Line Items]
Sales	$ 5,531.8	$ 5,094.7	$ 4,471.9
Percent sales by supply mode	44.00%	40.00%	43.00%
Merchant | Americas | Operating Segments
Disaggregation of Revenue [Line Items]
Sales	$ 2,225.4	$ 1,945.8	$ 1,698.1
Merchant | Asia | Operating Segments
Disaggregation of Revenue [Line Items]
Sales	1,293.1	1,309.4	1,202.0
Merchant | Europe | Operating Segments
Disaggregation of Revenue [Line Items]
Sales	1,926.5	1,787.9	1,543.2
Merchant | Middle East and India | Operating Segments
Disaggregation of Revenue [Line Items]
Sales	86.8	51.6	28.6
Merchant | Corporate and other | Operating Segments
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0	0.0
Sale of Equipment | Operating Segments
Disaggregation of Revenue [Line Items]
Sales	$ 889.0	$ 970.8	$ 789.7
Percent sales by supply mode	7.00%	8.00%	8.00%
Sale of Equipment | Americas | Operating Segments
Disaggregation of Revenue [Line Items]
Sales	$ 0.0	$ 0.0	$ 0.0
Sale of Equipment | Asia | Operating Segments
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0	0.0
Sale of Equipment | Europe | Operating Segments
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0	0.0
Sale of Equipment | Middle East and India | Operating Segments
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0	0.0
Sale of Equipment | Corporate and other | Operating Segments
Disaggregation of Revenue [Line Items]
Sales	$ 889.0	$ 970.8	$ 789.7