Credit Facilities, Short-term Borrowings and Long-term Debt (Narrative) (Details)		6 Months Ended	12 Months Ended
	Nov. 15, 2023 USD ($)	Mar. 31, 2025 USD ($)	Sep. 30, 2024 USD ($)
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity		$ 1,025,695,000
Outstanding borrowings		261,100,000
Borrowings outstanding		261,100,000	$ 217,000,000
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity		1,000,000,000
Line of credit facility, maximum borrowing capacity extension		1,500,000,000
Outstanding borrowings		261,100,000
Principal amount borrowing outstanding		$ 261,100,000	$ 217,000,000
Effective interest rate		0.0548	0.0582
Foreign Lines of Credit and Overdraft Facilities [Member]
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity		$ 25,600,000
Borrowings outstanding		$ 0	$ 0
Minimum [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt Instrument, Variable Interest Rate, Type [Extensible Enumeration]		Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]
Basis spread on variable rate		0.875%
Maximum [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt Instrument, Variable Interest Rate, Type [Extensible Enumeration]		Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]
Basis spread on variable rate		1.75%
Series H and K Notes [Member]
Debt Instrument [Line Items]
Payment of principal balance	$ 75,000,000