Fair Value Measurements (Schedule of the Carrying Values and Fair Values of Financial Instruments) (Details) - USD ($) $ in Millions	Mar. 31, 2023	Sep. 30, 2022
Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, including current portion and related party, carrying value	$ 9,133.9	$ 7,634.1
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, including current portion and related party, fair value	8,409.1	6,721.2
Forward exchange contracts | Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	110.2	138.6
Derivative liabilities	84.8	275.3
Forward exchange contracts | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	110.2	138.6
Derivative liabilities	84.8	275.3
Interest Rate Management Contracts | Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	15.6	50.5
Derivative liabilities	85.0	91.2
Interest Rate Management Contracts | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	15.6	50.5
Derivative liabilities	$ 85.0	$ 91.2