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Organization (Narrative) (Details) $ in Millions | 3 Months Ended |  |
--- | --- | --- | ---
Dec. 31, 2023 USD ($) business_segments | Dec. 31, 2022 USD ($) | Sep. 30, 2023 USD ($) | Sep. 30, 2022 USD ($)
Segment Reporting Information [Line Items] |  |  |  |
Restructuring | $ 7.8 | $ 0.7 | $ 6.6 | $ 3.3
Restructuring Reserve, Accrual Adjustment | 6.6 | (3.7) |  |
Gain (Loss) on Sale of Properties |  | 4.0 |  |
Restructuring and other charges | 6.6 | (3.7) |  |
Pension costs (benefits) other then service | $ 1.0 | $ 0.9 |  |
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent | 21.00% | 21.00% |  |
Number of Reportable Segments | business_segments | 2 |  |  |
Other Sundry Liabilities, Noncurrent | $ 3.9 |  |  |
Proceeds from Other Equity, Gross Amount | 4.8 |  |  |
Intercompany Loan related to NMTC | 12.2 |  |  |
Investment Fund Contribution for NMTC | 16.5 |  |  |
Sub-CDE loan from NMTC | 16.2 |  |  |
Cybersecurity Related |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Restructuring Reserve, Accrual Adjustment | 1.5 |  |  |
Mueller Co. [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Restructuring and other charges | $ 0.2 | $ 0.0 |  |

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