CONSOLIDATED BALANCE SHEETS (UNAUDITED) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Current assets
Cash and cash equivalents	$ 11.4	$ 1.3
Accounts receivable, net	53.8	59.2
Accrued unbilled revenues	40.8	53.1
Inventories	16.6	16.0
Regulatory assets	29.1	71.9
Prepaid taxes	18.1	23.0
Prepayments and other	6.3	4.6
Total current assets	176.1	229.1
Property, Plant and Equipment, Net [Abstract]
Property, plant and equipment, net	2,452.4	2,359.4
Other assets
Regulatory assets	216.8	224.4
Other	3.9	3.1
Total other assets	220.7	227.5
Total assets	2,849.2	2,816.0
Current liabilities
Short-term debt	0.0	65.0
Accounts payable	35.2	53.6
Accounts payable to affiliates	17.2	19.0
Dividends payable to parent	18.2	14.7
Regulatory liabilities	42.5	78.9
Taxes accrued	12.6	6.8
Environmental liabilities	3.9	5.7
Accrued interest	9.0	9.3
Other	16.0	20.7
Total current liabilities	154.6	273.7
Deferred credits and other liabilities
Deferred income taxes	303.9	298.1
Deferred investment tax credits	6.1	6.5
Regulatory liabilities	354.3	370.8
Environmental liabilities	16.6	17.8
Customer advances	20.5	18.5
Pension and employee benefit obligations	27.0	33.4
Other	23.2	22.6
Total deferred credits and other liabilities	751.6	767.7
Capitalization
Long-term debt	906.0	808.0
Common Stock - 1,000,000 shares authorized of $100 par value; 933,000 shares outstanding at Sept. 30, 2020 and Dec. 31, 2019, respectively	$ 93.3	$ 93.3
Common stock, shares authorized (in shares)	1,000,000	1,000,000
Common stock, par value (in dollars per share)	$ 100	$ 100
Common stock, shares outstanding (in shares)	933,000	933,000
Additional paid in capital	$ 577.8	$ 537.3
Retained earnings	365.9	336.0
Total common stockholder's equity	1,037.0	966.6
Total liabilities and equity	$ 2,849.2	$ 2,816.0