Capitalization and Short-Term Borrowings - Weighted Average Assumptions Used in Estimating Fair Value (Details) - Performance Shares	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-Free Interest Rate	4.03%	0.85%	0.19%
Remaining Term at Date of Grant (Years)	2 years 9 months 18 days	2 years 9 months 18 days	2 years 9 months 18 days
Expected Volatility	31.60%	29.70%	29.10%