Condensed Consolidated Balance Sheets - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 44.3	$ 26.6
Accounts Receivable, after Allowance for Credit Loss, Current	89.6	71.5
Inventories	20.9	14.4
Taxes applicable to subsequent years	20.3	83.1
Regulatory assets, current	27.2	24.5
Income Taxes Receivable, Current	3.6	2.7
Prepayments and other current assets	11.4	7.6
Total current assets	217.3	230.4
Property, plant & equipment:
Property, plant & equipment	2,120.9	1,990.4
Less: Accumulated depreciation and amortization	(483.5)	(464.0)
Property, plant and equipment, net of depreciation	1,637.4	1,526.4
Construction work in process	183.5	174.4
Total net property, plant & equipment	1,820.9	1,700.8
Other non-current assets:
Regulatory assets, non-current	134.9	176.8
Intangible assets, net of amortization	50.1	33.7
Other non-current assets	29.8	30.1
Total other non-current assets	214.8	240.6
Total assets	2,253.0	2,171.8
Current liabilities:
Current portion of long-term debt	100.2	65.2
Accounts payable	94.2	111.0
Accrued taxes	91.4	85.1
Accrued interest	20.4	15.3
Contract with Customer, Liability, Current	15.5	15.0
Regulatory liabilities, current	38.1	14.6
Other current liabilities	17.0	17.1
Total current liabilities	376.8	323.3
Non-current liabilities:
Long-term debt	1,535.4	1,395.3
Deferred Tax Liabilities, Net	184.1	187.9
Taxes payable	0.4	83.6
Regulatory liabilities, non-current	217.9	229.3
Pension, retiree and other benefits	53.1	62.3
Other deferred credits	10.6	11.5
Total non-current liabilities	2,001.5	1,969.9
Commitments and contingencies
Common shareholder's equity:
Common stock	0.0	0.0
Other paid-in capital	2,601.3	2,601.3
Accumulated other comprehensive income	(4.6)	(4.8)
Retained Earnings (Accumulated Deficit)	(2,722.0)	(2,717.9)
Total common shareholder's equity	(125.3)	(121.4)
Total liabilities and shareholder's equity	$ 2,253.0	$ 2,171.8
Common Stock, Shares Authorized	1,500	1,500
Common stock, shares issued	1	1
Subsidiaries [Member]
Current assets:
Cash and cash equivalents	$ 27.6	$ 14.4
Accounts Receivable, after Allowance for Credit Loss, Current	89.6	71.9
Inventories	20.9	14.4
Taxes applicable to subsequent years	20.2	83.0
Regulatory assets, current	27.2	24.5
Income Taxes Receivable, Current	24.9	28.1
Prepayments and other current assets	12.6	8.0
Total current assets	223.0	244.3
Property, plant & equipment:
Property, plant & equipment	2,685.9	2,571.3
Less: Accumulated depreciation and amortization	(1,068.3)	(1,062.6)
Property, plant and equipment, net of depreciation	1,617.6	1,508.7
Construction work in process	180.3	170.5
Total net property, plant & equipment	1,797.9	1,679.2
Other non-current assets:
Regulatory assets, non-current	134.9	176.8
Intangible assets, net of amortization	48.8	32.4
Other non-current assets	30.1	29.9
Total other non-current assets	213.8	239.1
Total assets	2,234.7	2,162.6
Current liabilities:
Current portion of long-term debt	55.2	0.2
Accounts payable	93.4	111.5
Accrued taxes	89.1	85.1
Accrued interest	7.9	2.6
Contract with Customer, Liability, Current	15.1	14.9
Regulatory liabilities, current	38.1	14.6
Other current liabilities	13.7	13.0
Total current liabilities	312.5	241.9
Non-current liabilities:
Long-term debt	712.7	574.1
Deferred Tax Liabilities, Net	183.9	183.4
Taxes payable	0.4	83.5
Regulatory liabilities, non-current	217.9	229.3
Pension, retiree and other benefits	53.1	62.3
Other deferred credits	5.2	5.9
Total non-current liabilities	1,173.2	1,138.5
Commitments and contingencies
Par value common shares (in USD per share)	$ 0.01	$ 0.01
Common shareholder's equity:
Common stock	$ 0.4	$ 0.4
Other paid-in capital	788.6	822.5
Accumulated other comprehensive income	(29.8)	(31.8)
Retained Earnings (Accumulated Deficit)	(10.2)	(8.9)
Total common shareholder's equity	749.0	782.2
Total liabilities and shareholder's equity	$ 2,234.7	$ 2,162.6
Common Stock, Shares, Outstanding	41,172,173	41,172,173
Common Stock, Shares Authorized	50,000,000	50,000,000