Fair Value (Fair Value of Assets and Liabilities Measured on Recurring Basis) (Details) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Level 1 [Member]
Total Assets	$ 0.4	$ 0.4
Level 1 [Member] \| Subsidiaries [Member]
Total Assets	0.4	0.4
Level 2 [Member]
Total Assets	7.1	9.0
Level 2 [Member] \| Subsidiaries [Member]
Total Assets	7.1	9.0
Level 3 [Member]
Total Assets	0.0	0.0
Level 3 [Member] \| Subsidiaries [Member]
Total Assets	0.0	0.0
Fair Value [Member]
Total Assets	7.5	9.4
Fair Value [Member] \| Subsidiaries [Member]
Total Assets	7.5	9.4
Money Market Funds [Member] \| Level 1 [Member]
Investments, Fair Value Disclosure	0.4	0.4
Money Market Funds [Member] \| Level 1 [Member] \| Subsidiaries [Member]
Investments, Fair Value Disclosure	0.4	0.4
Money Market Funds [Member] \| Level 2 [Member]
Investments, Fair Value Disclosure	0.0	0.0
Money Market Funds [Member] \| Level 2 [Member] \| Subsidiaries [Member]
Investments, Fair Value Disclosure	0.0	0.0
Money Market Funds [Member] \| Level 3 [Member]
Investments, Fair Value Disclosure	0.0	0.0
Money Market Funds [Member] \| Level 3 [Member] \| Subsidiaries [Member]
Investments, Fair Value Disclosure	0.0	0.0
Money Market Funds [Member] \| Fair Value [Member]
Investments, Fair Value Disclosure	0.4	0.4
Money Market Funds [Member] \| Fair Value [Member] \| Subsidiaries [Member]
Investments, Fair Value Disclosure	0.4	0.4
Equity Securities [Member] \| Level 1 [Member]
Investments, Fair Value Disclosure	0.0	0.0
Equity Securities [Member] \| Level 1 [Member] \| Subsidiaries [Member]
Investments, Fair Value Disclosure	0.0	0.0
Equity Securities [Member] \| Level 2 [Member]
Investments, Fair Value Disclosure	3.8	5.1
Equity Securities [Member] \| Level 2 [Member] \| Subsidiaries [Member]
Investments, Fair Value Disclosure	3.8	5.1
Equity Securities [Member] \| Level 3 [Member]
Investments, Fair Value Disclosure	0.0	0.0
Equity Securities [Member] \| Level 3 [Member] \| Subsidiaries [Member]
Investments, Fair Value Disclosure	0.0	0.0
Equity Securities [Member] \| Fair Value [Member]
Investments, Fair Value Disclosure	3.8	5.1
Equity Securities [Member] \| Fair Value [Member] \| Subsidiaries [Member]
Investments, Fair Value Disclosure	3.8	5.1
Debt Securities [Member] \| Level 1 [Member]
Investments, Fair Value Disclosure	0.0	0.0
Debt Securities [Member] \| Level 1 [Member] \| Subsidiaries [Member]
Investments, Fair Value Disclosure	0.0	0.0
Debt Securities [Member] \| Level 2 [Member]
Investments, Fair Value Disclosure	3.3	3.9
Debt Securities [Member] \| Level 2 [Member] \| Subsidiaries [Member]
Investments, Fair Value Disclosure	3.3	3.9
Debt Securities [Member] \| Level 3 [Member]
Investments, Fair Value Disclosure	0.0	0.0
Debt Securities [Member] \| Level 3 [Member] \| Subsidiaries [Member]
Investments, Fair Value Disclosure	0.0	0.0
Debt Securities [Member] \| Fair Value [Member]
Investments, Fair Value Disclosure	3.3	3.9
Debt Securities [Member] \| Fair Value [Member] \| Subsidiaries [Member]
Investments, Fair Value Disclosure	3.3	3.9
Debt [Member] \| Level 1 [Member]
Debt	0.0	0.0
Debt [Member] \| Level 1 [Member] \| Subsidiaries [Member]
Debt	0.0	0.0
Debt [Member] \| Level 2 [Member]
Debt	1,399.6	1,502.5
Debt [Member] \| Level 2 [Member] \| Subsidiaries [Member]
Debt	647.2	625.4
Debt [Member] \| Level 3 [Member]
Debt	17.1	17.2
Debt [Member] \| Level 3 [Member] \| Subsidiaries [Member]
Debt	17.1	17.2
Debt [Member] \| Fair Value [Member]
Debt	1,416.7	1,519.7
Debt [Member] \| Fair Value [Member] \| Subsidiaries [Member]
Debt	$ 664.3	$ 642.6

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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-Publisher FASB
-Name Accounting Standards Codification
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Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method.

+ References

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