Fair Value Measurements (Schedule of Recurring Fair Value Measurements) (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Millions	Mar. 31, 2025	Sep. 30, 2024
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Assets at Fair Value	$ 239.2	$ 142.6
Total Liabilities at Fair Value	123.9	100.6
Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Assets at Fair Value	0.0	0.0
Total Liabilities at Fair Value	0.0	0.0
Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Assets at Fair Value	239.2	142.6
Total Liabilities at Fair Value	123.9	100.6
Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Assets at Fair Value	0.0	0.0
Total Liabilities at Fair Value	0.0	0.0
Forward exchange contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	51.6	100.8
Derivative liabilities	86.8	59.2
Forward exchange contracts | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	0.0	0.0
Derivative liabilities	0.0	0.0
Forward exchange contracts | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	51.6	100.8
Derivative liabilities	86.8	59.2
Forward exchange contracts | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	0.0	0.0
Derivative liabilities	0.0	0.0
Interest Rate Management Contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	187.6	41.8
Derivative liabilities	37.1	41.4
Interest Rate Management Contracts | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	0.0	0.0
Derivative liabilities	0.0	0.0
Interest Rate Management Contracts | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	187.6	41.8
Derivative liabilities	37.1	41.4
Interest Rate Management Contracts | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	0.0	0.0
Derivative liabilities	$ 0.0	$ 0.0