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Regulatory Matters (Regulatory Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Regulated Operations [Line Items]
Regulatory Liabilities	$ 2,012.6	$ 1,980.0
Regulatory Liability, Current	236.8	137.4
Regulatory Liability, Noncurrent	1,775.8	1,842.6
Deferred Derivative Gain (Loss)
Regulated Operations [Line Items]
Regulatory Liabilities	90.0	34.2
Customer Assistance Programs
Regulated Operations [Line Items]
Regulatory Liabilities	32.9	13.2
Rate Refunds
Regulated Operations [Line Items]
Regulatory Liabilities	51.4	8.2
Overrecovered Gas And Fuel Costs
Regulated Operations [Line Items]
Regulatory Liabilities	20.6	5.4
Cost Of Removal
Regulated Operations [Line Items]
Regulatory Liabilities	675.9	749.5
Regulatory Effects Of Accounting For Income Taxes
Regulated Operations [Line Items]
Regulatory Liabilities	996.3	1,040.8
Other Postretirement Costs
Regulated Operations [Line Items]
Regulatory Liabilities	66.8	75.9
Other Liabilities
Regulated Operations [Line Items]
Regulatory Liabilities	$ 78.7	$ 52.8

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Regulated Operations [Line Items]

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The amount for the individual regulatory liability as itemized in a table of regulatory liabilities as of the end of the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 980
-SubTopic 405
-Section 25
-Paragraph 1
-URI https://asc.fasb.org/extlink&oid=6500807&loc=d3e48068-110394

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The amount for the individual regulatory current liability as itemized in a table of regulatory current liabilities as of the end of the period.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 980
-SubTopic 405
-Section 25
-Paragraph 1
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The amount for the individual regulatory noncurrent liability as itemized in a table of regulatory noncurrent liabilities as of the end of the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.24)
-URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

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