Capitalization and Short-Term Borrowings - Weighted Average Assumptions Used in Estimating Fair Value (Details) - Performance Shares	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-Free Interest Rate	4.36%	4.03%	0.85%
Remaining Term at Date of Grant (Years)	2 years 11 months 23 days	2 years 9 months 18 days	2 years 9 months 18 days
Expected Volatility	23.90%	31.60%	29.70%