Fair Value Measurements (Schedule of the Carrying Values and Fair Values of Financial Instruments) (Details) - USD ($) $ in Millions	Sep. 30, 2021	Sep. 30, 2020
Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, including current portion carrying value	$ 7,634.8	$ 7,900.1
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, including current portion fair value	7,812.2	8,278.4
Forward exchange contracts | Carrying Value
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 | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	49.3	83.6
Derivative liabilities	88.8	83.5
Interest rate management contracts | Carrying Value
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 | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	34.1	59.7
Derivative liabilities	$ 32.7	$ 2.1