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Jointly-Owned Facilities and Assets - Table (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Jointly-Owned Facilities and Assets [Line Items]
Plant in Service	$ 826.9	$ 813.0
Accumulated Depreciation	393.4	361.2
Construction Work in Progress	2.8	3.3
Transmission Assets | Transmission Assets
Jointly-Owned Facilities and Assets [Line Items]
Plant in Service	101.0	101.0
Accumulated Depreciation	23.6	21.1
Construction Work in Progress	$ 0.0	$ 0.0
Transmission Assets | Transmission Assets | Minimum
Jointly-Owned Facilities and Assets [Line Items]
% Ownership	9.30%	9.30%
Transmission Assets | Transmission Assets | Maximum
Jointly-Owned Facilities and Assets [Line Items]
% Ownership	14.70%	14.70%
Boswell Unit 4 | Boswell Unit 4
Jointly-Owned Facilities and Assets [Line Items]
Plant in Service	$ 725.9	$ 712.0
Accumulated Depreciation	369.8	340.1
Construction Work in Progress	$ 2.8	$ 3.3
% Ownership	80.00%	80.00%

X

- Definition

The period end amount owned by the reporting utility of a jointly owned utility plant in service.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 980
-SubTopic 360
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 10.C)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479960/980-360-S99-1

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- Definition

The period end amount of construction work in progress at a jointly owned electricity generation plant.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 980
-SubTopic 360
-Name Accounting Standards Codification
-Section S99
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-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479960/980-360-S99-1

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- Definition

The period end amount of accumulated depreciation in a jointly owned electricity generation plant.

+ References

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-SubTopic 360
-Name Accounting Standards Codification
-Section S99
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-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479960/980-360-S99-1

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- Definition

The proportionate share of interest (percent) in a jointly owned utility plant.

+ References

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-SubTopic 360
-Name Accounting Standards Codification
-Section S99
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-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479960/980-360-S99-1

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