Condensed Consolidated Statements of Operations - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Revenues	$ 262.1	$ 188.2	$ 652.3	$ 511.5
Operating costs and expenses
Net fuel cost	0.0	0.0	0.0	0.5
Utilities Operating Expense, Purchased Power	180.2	83.9	361.6	209.3
Operating expenses:
Operation and maintenance	48.8	40.1	132.7	112.9
Depreciation and amortization	20.0	18.9	59.6	56.9
Taxes other than income taxes	20.4	21.0	63.6	62.1
Gain (Loss) on Sale of Assets and Asset Impairment Charges, excluding Discontinued Operations	0.0	0.0	(0.6)	0.0
Costs and Expenses	269.4	163.9	616.9	441.7
Operating income / (loss)	(7.3)	24.3	35.4	69.8
Other expense, net:
Interest expense	(18.1)	(15.8)	(50.1)	(47.0)
Other income	1.6	(0.8)	2.0	0.3
Total other expense, net	(16.5)	(16.6)	(48.1)	(46.7)
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	(23.8)	7.7	(12.7)	23.1
Income tax benefit from continuing operations	(4.1)	(0.8)	(8.6)	(0.2)
Net income / (loss) from continuing operations	(19.7)	8.5	(4.1)	23.3
Loss from discontinued operations before income tax	0.0	0.0	0.0	(1.0)
Income tax benefit from discontinued operations	0.0	0.0	0.0	(0.2)
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	0.0	0.0	0.0	(0.8)
Net income / (loss)	(19.7)	8.5	(4.1)	22.5
Subsidiaries [Member]
Revenues	259.9	186.1	645.6	504.8
Operating costs and expenses
Net fuel cost	0.0	0.0	0.0	0.5
Utilities Operating Expense, Purchased Power	179.8	83.7	360.6	208.5
Operating expenses:
Operation and maintenance	48.2	39.3	131.3	111.6
Depreciation and amortization	19.8	18.6	58.7	55.8
Taxes other than income taxes	20.4	21.0	63.4	62.0
Gain (Loss) on Sale of Assets and Asset Impairment Charges, excluding Discontinued Operations	0.0	0.0	(0.6)	0.0
Costs and Expenses	268.2	162.6	613.4	438.4
Operating income / (loss)	(8.3)	23.5	32.2	66.4
Other expense, net:
Interest expense	(8.4)	(6.1)	(21.1)	(18.1)
Other income	1.1	(1.3)	0.2	(1.6)
Total other expense, net	(7.3)	(7.4)	(20.9)	(19.7)
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	(15.6)	16.1	11.3	46.7
Income tax benefit from continuing operations	(5.5)	2.7	(2.8)	6.4
Net income / (loss)	$ (10.1)	$ 13.4	$ 14.1	$ 40.3