Condensed Consolidated Statements of Operations - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Revenues	$ 227.5	$ 224.2	$ 663.1	$ 666.3
OPERATING COSTS AND EXPENSES:
Net purchased power cost	84.3	67.2	243.5	276.9
Operation and maintenance	66.9	56.6	188.9	170.7
Depreciation and amortization	25.7	20.6	69.4	60.9
Taxes other than income taxes	28.1	25.2	84.4	77.4
Loss on asset disposal	0.0	0.0	1.3	0.0
Costs and Expenses	205.0	169.6	587.5	585.9
OPERATING INCOME	22.5	54.6	75.6	80.4
OTHER INCOME / (EXPENSE), NET:
Interest expense, net	(21.1)	(7.8)	(62.2)	(45.2)
Other income, net	1.4	1.4	5.1	4.7
Total other expense, net	(19.7)	(6.4)	(57.1)	(40.5)
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	2.8	48.2	18.5	39.9
Income tax expense / (benefit)	(7.5)	9.6	(4.6)	5.3
NET INCOME	10.3	38.6	23.1	34.6
Subsidiaries [Member]
Revenues	225.4	222.0	656.6	659.5
OPERATING COSTS AND EXPENSES:
Net purchased power cost	84.1	67.2	242.8	276.4
Operation and maintenance	66.3	56.7	187.8	169.1
Depreciation and amortization	25.2	20.3	68.0	59.9
Taxes other than income taxes	28.1	25.2	84.2	77.3
Loss on asset disposal	0.0	0.0	1.1	0.0
Costs and Expenses	203.7	169.4	583.9	582.7
OPERATING INCOME	21.7	52.6	72.7	76.8
OTHER INCOME / (EXPENSE), NET:
Interest expense, net	(11.8)	1.3	(34.7)	(16.7)
Other income, net	0.7	1.2	3.2	4.0
Total other expense, net	(11.1)	2.5	(31.5)	(12.7)
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	10.6	55.1	41.2	64.1
Income tax expense / (benefit)	(1.9)	11.5	4.2	11.3
NET INCOME	$ 12.5	$ 43.6	$ 37.0	$ 52.8