CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Operating Activities:
Net Income	$ 45.2	$ 41.4	$ 36.1
Adjustments to Reconcile Net Income to Cash Provided by Operating Activities:
Depreciation and Amortization	67.4	62.6	59.5
Deferred Tax Provision	7.4	11.0	10.8
Changes in Working Capital Items:
Accounts Receivable	(1.2)	(6.9)	(4.9)
Accrued Revenue	9.4	(11.6)	(10.3)
Regulatory Liabilities	(1.5)	5.5	4.0
Exchange Gas Receivable	8.6	(10.6)	(2.5)
Accounts Payable	(20.9)	16.2	19.2
Other Changes in Working Capital Items	1.0	1.4	0.7
Deferred Regulatory and Other Charges	(8.5)	(6.5)	(2.7)
Other, net	0.1	(4.8)	(2.1)
Cash Provided by Operating Activities	107.0	97.7	107.8
Investing Activities:
Property, Plant and Equipment Additions	(141.0)	(122.1)	(115.0)
Cash Used In Investing Activities	(141.0)	(122.1)	(115.0)
Financing Activities:
Proceeds from (Repayment of) Short-Term Debt, net	46.0	51.9	9.4
Issuance of Long-Term Debt	25.0	0.0	0.0
Repayment of Long-Term Debt	(6.9)	(10.4)	(25.8)
Long-Term Debt Issuance Costs	(0.2)	0.0	0.0
(Decrease) Increase in Capital Lease Obligations	0.3	(0.1)	(0.1)
Net Increase (Decrease) in Exchange Gas Financing	(7.6)	9.6	2.3
Dividends Paid	(26.2)	(25.1)	(23.6)
Proceeds from Issuance of Common Stock	1.1	1.0	45.5
Cash Provided by (Used In) Financing Activities	31.5	26.9	7.7
Net Increase (Decrease) in Cash and Cash Equivalents	(2.5)	2.5	0.5
Cash and Cash Equivalents at Beginning of Year	9.0	6.5	6.0
Cash and Cash Equivalents at End of Year	6.5	9.0	6.5
Supplemental Information:
Interest Paid	30.9	26.0	26.0
Income Taxes Paid	0.0	1.2	1.4
Payments on Capital Leases	0.2	0.2	0.2
Capital Expenditures Included in Accounts Payable	7.5	7.3	4.9
Right-of-Use Assets Obtained in Exchange for Lease Obligations	$ 2.7	$ 1.1	$ 0.7