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v3.23.3

Note 1 - Summary of Significant Accounting Policies (Details Textual) - USD ($) $ in Millions |  | 12 Months Ended
--- | --- | ---
Apr. 01, 2023 | Sep. 30, 2023 | Sep. 30, 2022 | Sep. 30, 2021
Number of Reportable Segments |  | 3 |  |
Difference Between Replacement Cost of Gas Storage and Inventory Basis Amount |  | $ 21.1 | $ 37.3 |
Goodwill |  | 1,171.6 | 1,171.6 |
Payments to Acquire Businesses, Gross | $ 37.0 | 37.0 | (0.0) | $ (0.0)
Restricted Cash |  | 20.2 | $ 14.0 |
Gas Utility [Member] |  |  |  |
Goodwill |  | $ 210.2 |  |
Spire Alabama Inc [Member] |  |  |  |
Public Utilities, Property, Plant and Equipment, Disclosure of Composite Depreciation Rate for Plants in Service |  | 3.00% | 3.00% | 3.00%
Financing Receivable, after Allowance for Credit Loss |  | $ 6.7 | $ 7.1 |
Spire Alabama Inc [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] |  |  |  |
Financing Receivable, before Allowance for Credit Loss |  | $ 0.3 | $ 0.3 |
Spire Missouri [Member] |  |  |  |
Public Utilities, Property, Plant and Equipment, Disclosure of Composite Depreciation Rate for Plants in Service |  | 3.00% | 3.00% | 3.00%
Goodwill |  | $ 210.2 | $ 210.2 |

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