Benefit Plans Asset Holdings (Details) - USD ($)	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Defined Benefit Plan Disclosure
Target Allocation	100.00%
Plan Asset Allocations	100.00%	100.00%
Growth Assets
Defined Benefit Plan Disclosure
Target Allocation	68.00%
Plan Asset Allocations	59.00%	58.00%
Defensive growth assets
Defined Benefit Plan Disclosure
Target Allocation	20.00%
Plan Asset Allocations	23.00%	25.00%
Defensive Assets
Defined Benefit Plan Disclosure
Target Allocation	12.00%
Plan Asset Allocations	18.00%	17.00%
Other Post-retirement Benefits
Defined Benefit Plan Disclosure
Actuarial assumption COLA	$ 0.0277	$ 0.0444	$ 0.06