Benefit Plans (Other Changes in Plan Assets and Benefit Obligation Recognized in Accumulated Other Comprehensive Income, Regulatory Assets And Regulatory Liabilities) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Defined Benefit Plan Disclosure [Line Items]
Prior service cost for the period, net of income tax benefit/(expense)	$ (0.2)	$ (0.1)	$ 0.3
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)	2.7	(12.4)
Postretirement [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Funded (Unfunded) Status of Plan	8.6	7.9
Pension [Member]
Defined Benefit Plan Disclosure [Line Items]
Reversal of amortization item, Net actuarial (gain) / loss	(3.2)	(2.1)	(0.6)
Reversal of amortization item, Prior service cost / (credit)	(1.0)	(1.0)	(1.0)
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax	(12.3)	(5.7)	0.5
Total recognized in net periodic benefit cost and Accumulated other comprehensive income, Regulatory assets and Regulatory liabilities	(7.2)	(0.3)	3.3
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, before Tax	(8.1)	(2.6)	0.7
Prior service cost for the period, net of income tax benefit/(expense)	0.0	0.0	$ 1.4
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)	2.7	(12.4)
Defined Benefit Plan, Funded (Unfunded) Status of Plan	$ (7.5)	$ (22.3)