Condensed Consolidated Statements of Operations - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Revenues	$ 188.2	$ 178.8	$ 511.5	$ 505.1
Operating costs and expenses
Net fuel cost	0.0	0.4	0.5	1.3
Utilities Operating Expense, Purchased Power	83.9	66.0	209.3	178.0
Operating expenses:
Operation and maintenance	40.1	48.0	112.9	138.8
Depreciation and amortization	18.9	18.6	56.9	54.8
Taxes other than income taxes	21.0	17.7	62.1	59.6
Costs and Expenses	163.9	150.7	441.7	432.5
Operating income	24.3	28.1	69.8	72.6
Other expense, net:
Interest expense	(15.8)	(17.1)	(47.0)	(55.4)
Gain (Loss) on Extinguishment of Debt	0.0	(31.7)	0.0	(31.7)
Other income / (expense)	(0.8)	1.0	0.3	0.9
Total other expense, net	(16.6)	(47.8)	(46.7)	(86.2)
Income / (loss) from continuing operations before income tax	7.7	(19.7)	23.1	(13.6)
Income tax benefit from continuing operations	(0.8)	(10.4)	(0.2)	(7.7)
Net income / (loss) from continuing operations	8.5	(9.3)	23.3	(5.9)
Income / (loss) from discontinued operations before income tax	0.0	1.4	(1.0)	(0.6)
Income tax expense / (benefit) from discontinued operations	0.0	0.3	(0.2)	0.8
Net income / (loss) from discontinued operations	0.0	1.1	(0.8)	3.1
Net income / (loss)	8.5	(8.2)	22.5	(2.8)
Subsidiaries [Member]
Revenues	186.1	177.0	504.8	499.1
Operating costs and expenses
Net fuel cost	0.0	0.4	0.5	1.3
Utilities Operating Expense, Purchased Power	83.7	65.7	208.5	177.1
Operating expenses:
Operation and maintenance	39.3	47.9	111.6	137.8
Depreciation and amortization	18.6	18.2	55.8	53.7
Taxes other than income taxes	21.0	17.8	62.0	59.6
Costs and Expenses	162.6	150.0	438.4	429.5
Operating income	23.5	27.0	66.4	69.6
Other expense, net:
Interest expense	(6.1)	(5.9)	(18.1)	(18.5)
Other income / (expense)	(1.3)	0.2	(1.6)	(1.4)
Total other expense, net	(7.4)	(5.7)	(19.7)	(19.9)
Income / (loss) from continuing operations before income tax	16.1	21.3	46.7	49.7
Income tax benefit from continuing operations	2.7	3.5	6.4	2.4
Net income / (loss)	$ 13.4	$ 17.8	$ 40.3	$ 47.3