Consolidated Statement of Cash Flows - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Operating Activities [Abstract]
Net Income	$ 94.1	$ 89.2
AFUDC – Equity	(2.4)	(1.7)
Income from Equity Investments – Net of Dividends	3.8	1.8
Loss (Gain) on Investments and Property, Plant and Equipment	2.1	(0.7)
Depreciation Expense	181.3	173.4
Amortization of PSAs	(6.3)	(8.6)
Amortization of Other Intangible Assets and Other Assets	6.3	7.4
Deferred Income Tax Benefit	(19.7)	(19.4)
Share-Based and ESOP Compensation Expense	4.2	4.6
Defined Benefit Pension and Postretirement Benefit Expense (Benefit)	(2.2)	3.3
Fuel Adjustment Clause	(3.5)	(30.1)
Bad Debt Expense	1.4	0.9
Residential Interim Rate Adjustment	(5.9)	0.0
Changes in Operating Assets and Liabilities [Abstract]
Accounts Receivable	3.2	0.8
Inventories	(261.4)	(15.4)
Prepayments and Other	(7.7)	7.9
Accounts Payable	8.0	4.0
Other Current Liabilities	63.5	20.7
Cash Contributions to Defined Benefit Pension Plans	0.0	(10.3)
Changes in Regulatory and Other Non-Current Assets	28.0	(11.2)
Changes in Regulatory and Other Non-Current Liabilities	(5.6)	(7.4)
Cash provided by Operating Activities	81.2	209.2
Investing Activities [Abstract]
Proceeds from Sale of Available-for-sale Securities	1.7	3.3
Payments for Purchase of Available-for-sale Securities	(1.7)	(3.0)
Payments to Acquire Businesses, Net of Cash Acquired	(155.0)	0.0
Payments for Equity Method Investments	(5.1)	(17.4)
Additions to Property, Plant and Equipment	(152.0)	(384.3)
Other Investing Activities	1.0	4.3
Cash used in Investing Activities	(311.1)	(397.1)
Financing Activities [Abstract]
Proceeds from Issuance of Common Stock	244.4	31.0
Equity Issuance Costs	(8.1)	0.0
Proceeds from Issuance of Short-Term and Long-Term Debt	720.5	510.6
Repayments of Short-Term and Long-Term Debt	(771.0)	(280.9)
Proceeds from Non-controlling Interest in Subsidiaries - Net	155.7	28.9
Dividends on Common Stock	(108.6)	(98.7)
Other Financing Activities	(2.1)	(2.8)
Cash provided by Financing Activities	230.8	188.1
Change in Cash, Cash Equivalents and Restricted Cash	0.9	0.2
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	$ 48.6	$ 65.4