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Summary of Significant Accounting Policies - Components of Energy Supply Obligations (Detail) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023	Sep. 30, 2023
Contractual Obligation [Line Items]
Energy Supply Obligations-Current	$ 12.8	$ 15.0	$ 18.7
Exchange Gas Obligation
Contractual Obligation [Line Items]
Energy Supply Obligations-Current	8.8	6.4	13.1
Renewable Energy Portfolio Standards
Contractual Obligation [Line Items]
Energy Supply Obligations-Current	$ 4.0	$ 8.6	$ 5.6

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- Definition

Current liabilities attributable to energy marketing activities (trading activities). Current energy marketing (trading activities) are when entities engage in both financial and physical trading to increase profits, manage their commodity price risk and enhance system reliability. They may trade electricity, coal, natural gas and oil. These entities typically use a variety of financial instruments, including forward contracts, options and swaps.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(20))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

+ Details

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- Definition

Contractual Obligation [Line Items]

+ References

No definition available.

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