Fair Value (Fair Value of Assets and Liabilities Measured on Recurring Basis) (Details) - USD ($) $ in Millions	Mar. 31, 2026	Dec. 31, 2025
Long-term Debt	$ 1,798.8	$ 1,798.3
Level 1 [Member]
Total Assets	7.6	8.3
Level 2 [Member]
Total Assets	0.0	0.0
Level 3 [Member]
Total Assets	0.0	0.0
Fair Value [Member]
Total Assets	7.6	8.3
Money Market Funds [Member] \| Level 1 [Member]
Investments, Fair Value Disclosure	0.3	0.8
Money Market Funds [Member] \| Level 2 [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] \| Fair Value [Member]
Investments, Fair Value Disclosure	0.3	0.8
Debt [Member] \| Level 1 [Member]
Debt	0.0	0.0
Debt [Member] \| Level 2 [Member]
Debt	1,838.0	1,684.3
Debt [Member] \| Level 3 [Member]
Debt	17.8	16.4
Debt [Member] \| Fair Value [Member]
Debt	1,855.8	1,700.7
Mutual Fund \| Level 1 [Member]
Investments, Fair Value Disclosure	7.3	7.5
Mutual Fund \| Level 2 [Member]
Investments, Fair Value Disclosure	0.0	0.0
Mutual Fund \| Level 3 [Member]
Investments, Fair Value Disclosure	0.0	0.0
Mutual Fund \| Fair Value [Member]
Investments, Fair Value Disclosure	7.3	7.5
Line of Credit \| Level 1 [Member]
Debt	0.0	0.0
Line of Credit \| Level 2 [Member]
Debt	31.8	0.0
Line of Credit \| Level 3 [Member]
Debt	0.0	0.0
Line of Credit \| Fair Value [Member]
Debt	$ 31.8	$ 0.0