Note 17 - Leases - Year-end Balance Sheet and Weighted-average Information About Operating Lease (Details) (Parentheticals) - USD ($) $ in Millions |
Sep. 30, 2024 |
Sep. 30, 2023 |
---|---|---|
Assets [Abstract] | ||
Regulatory and Other Assets, Noncurrent | $ 2,775.5 | $ 2,726.7 |
Liabilities, Current [Abstract] | ||
Other Liabilities, Current | 193.2 | 183.2 |
Liabilities, Noncurrent [Abstract] | ||
Other Liabilities, Noncurrent | $ 140.6 | $ 139.6 |
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration] | Regulatory and Other Assets, Noncurrent | Regulatory and Other Assets, Noncurrent |
US Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration] | Other Liabilities, Current | Other Liabilities, Current |
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration] | Other Liabilities, Noncurrent | Other Liabilities, Noncurrent |