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New Accounting Standards | 6 Months Ended
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Jun. 30, 2026
Accounting Standards Update and Change in Accounting Principle [Abstract] |
New Accounting Pronouncements | New Ac counti ng Standards - MGE Energy and MGE. In November 2024, the Financial Accounting Standards Board issued authoritative guidance within the codification's Income Statement - Reporting Comprehensive Income topic, which added disclosure requirements for the disaggregation of certain income statement expenses. The authoritative guidance will become effective for annual reporting periods beginning after December 15, 2026, and interim periods beginning after December 15, 2027. MGE will adopt the standard as of the effective date. The adoption of this standard will not have a material impact on MGE Energy's and MGE's financial statements. In September 2025, the Financial Accounting Standards Board issued authoritative guidance within the codification’s Internal-Use Software topic, which amends certain aspects of the accounting for and disclosure of software costs. The authoritative guidance will become effective for annual reporting periods beginning after December 15, 2027, and interim periods within those annual reporting periods; early adoption is permitted as of the beginning of an annual reporting period. MGE will adopt the standard as of the effective date. The adoption of this standard is not expected to have a material impact on MGE Energy's and MGE’s financial statements. In May 2026, the Financial Accounting Standards Board issued authoritative guidance within the codification’s Environmental Credits topic, which establishes a comprehensive model for the recognition, measurement, presentation, and disclosure of environmental credits and related obligations. The authoritative guidance will become effective for annual reporting periods beginning after December 15, 2027, and interim periods within those annual reporting periods; early adoption is permitted. MGE will adopt the standard as of the effective date. The adoption of this standard is not expected to have a material impact on MGE Energy's and MGE’s financial statements.

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- Definition The entire disclosure for change in accounting principle. 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