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Retirement Plans (Fair Value Asset Allocation) (Details) - USD ($) $ in Millions | Sep. 30, 2023 | Sep. 30, 2022
--- | --- | ---
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | $ 239.8 | $ 251.8
Fair Value, Inputs, Level 1 [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 194.2 | 201.7
Fair Value, Inputs, Level 2 [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 45.6 | 50.1
Equity Securities [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 71.2 | 74.6
Equity Securities [Member] | Fair Value, Inputs, Level 1 [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 71.2 | 74.6
Equity Securities [Member] | Fair Value, Inputs, Level 2 [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 0.0 | 0.0
Large Cap Growth Funds [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets |  | 37.2
Large Cap Growth Funds [Member] | Fair Value, Inputs, Level 1 [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets |  | 37.2
Large Cap Growth Funds [Member] | Fair Value, Inputs, Level 2 [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets |  | 0.0
Large Cap Index Funds [Member] [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 35.6 |
Large Cap Index Funds [Member] [Member] | Fair Value, Inputs, Level 1 [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 35.6 |
Large Cap Index Funds [Member] [Member] | Fair Value, Inputs, Level 2 [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 0.0 |
International Stocks [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 35.6 | 37.4
International Stocks [Member] | Fair Value, Inputs, Level 1 [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 35.6 | 37.4
International Stocks [Member] | Fair Value, Inputs, Level 2 [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 0.0 | 0.0
Fixed Income Funds [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 166.7 | 175.3
Fixed Income Funds [Member] | Fair Value, Inputs, Level 1 [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 121.1 | 125.2
Fixed Income Funds [Member] | Fair Value, Inputs, Level 2 [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 45.6 | 50.1
Cash and Cash Equivalents [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 1.9 | 1.9
Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 1.9 | 1.9
Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 2 [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | $ 0.0 | $ 0.0

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