Condensed Consolidated Statements of Operations - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Revenues	$ 240.1	$ 199.3
Operating costs and expenses
Utilities Operating Expense, Purchased Power	122.2	90.8
Operating expenses:
Operation and maintenance	54.0	40.8
Depreciation and amortization	19.8	19.5
Taxes other than income taxes	25.5	22.0
Gain (Loss) on Sale of Assets and Asset Impairment Charges, excluding Discontinued Operations	0.0	(0.6)
Costs and Expenses	221.5	172.5
Operating income	18.6	26.8
Other expense, net:
Interest expense	(18.1)	(15.5)
Other income	1.8	0.4
Total other expense, net	(16.3)	(15.1)
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	2.3	11.7
Income tax expense / (benefit)	1.1	(3.7)
Net income	1.2	15.4
Subsidiaries [Member]
Revenues	237.8	197.0
Operating costs and expenses
Utilities Operating Expense, Purchased Power	122.0	90.5
Operating expenses:
Operation and maintenance	53.2	40.2
Depreciation and amortization	19.4	19.2
Taxes other than income taxes	25.5	21.9
Gain (Loss) on Sale of Assets and Asset Impairment Charges, excluding Discontinued Operations	0.0	(0.6)
Costs and Expenses	220.1	171.2
Operating income	17.7	25.8
Other expense, net:
Interest expense	(8.3)	(5.9)
Other income	1.5	(0.3)
Total other expense, net	(6.8)	(6.2)
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	10.9	19.6
Income tax expense / (benefit)	1.3	2.7
Net income	$ 9.6	$ 16.9