Income Taxes (Components of Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Income Taxes [Line Items]
Relating to utility property, net	$ 255.5	$ 218.2
Deferred Tax Liabilities, Regulatory Assets and Liabilities	8.7	34.4
Compensation and employee benefits	3.7	4.5
Total deferred tax liabilities	271.0	257.1
Long-term debt	0.0	4.7
Other	3.1	0.0
Deferred Income Tax Liabilities, Net	233.0	249.6
Operating Loss Carryforwards	33.2	0.0
Deferred Tax Assets, Other	4.8	2.8
Deferred Tax Assets, Gross	$ 38.0	$ 7.5