XML 91 R75.htm IDEA: XBRL DOCUMENT v3.25.3
Income Taxes - Schedule of Reconciliation of U.S. Federal Statutory Tax Rate to Effective Tax Rate (Details)
 12 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2023
Operating Loss Carryforwards [Line Items]      
U.S. federal statutory tax rate 21.00% 21.00% 21.00%
Difference in tax rate due to:      
Goodwill impairment not deductible for tax 0.00% 11.60% (7.30%)
State income taxes, net of federal benefit 4.60% 6.80% (1.70%)
Investment tax credits (12.70%) (6.80%) 0.50%
Valuation allowance adjustments (8.80%) (6.30%) 1.10%
Regulated entity depreciation normalization (2.00%) (4.50%) 0.70%
Notional interest deduction (1.70%) (3.80%) 0.70%
Nontaxable sale of equity investment 1.50% 0.00% 0.00%
State NOL adjustment upon disposition 0.00% 2.40% 0.00%
Uncertain tax positions 0.80% (2.40%) (0.70%)
Impairment of equity investment 0.00% 2.20% 0.00%
Federal refund interest accrual (0.50%) (1.10%) 0.00%
Effects of foreign operations (0.60%) 0.10% 3.10%
Other, net 1.70% (1.90%) 0.60%
Effective tax rate 2.60% 20.90% 18.20%
Effects of tax rate changes – State, net of federal benefit      
Difference in tax rate due to:      
Effects of tax rate changes – State, net of federal benefit (0.70%) 3.60% 0.20%