Fair Value Measurements (Schedule of Recurring Fair Value Measurements) (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Millions	Sep. 30, 2021	Sep. 30, 2020
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Assets at Fair Value	$ 83.4	$ 143.3
Total Liabilities at Fair Value	121.5	85.6
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	83.4	143.3
Total Liabilities at Fair Value	121.5	85.6
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	49.3	83.6
Derivative liabilities	88.8	83.5
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	49.3	83.6
Derivative liabilities	88.8	83.5
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	34.1	59.7
Derivative liabilities	32.7	2.1
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	34.1	59.7
Derivative liabilities	32.7	2.1
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