Net Completed Plant Net Completed Plant (Details) - USD ($) $ in Millions	Sep. 30, 2025	Sep. 30, 2024
Completed Plant
Accumulated depreciation	$ 38,716	$ 38,793
Net completed plant	32,858	32,196
Property, Plant and Equipment, Gross	71,574	70,989
Coal-fired
Completed Plant
Completed plant cost	19,029	20,177
Accumulated depreciation	15,760	16,635
Net completed plant	3,269	3,542
Gas and oil-fired
Completed Plant
Completed plant cost	7,746	7,051
Accumulated depreciation	2,274	2,112
Net completed plant	5,472	4,939
Nuclear
Completed Plant
Completed plant cost	27,091	26,800
Accumulated depreciation	14,682	14,149
Net completed plant	12,409	12,651
Transmission
Completed Plant
Completed plant cost	10,323	9,964
Accumulated depreciation	3,542	3,450
Net completed plant	6,781	6,514
Hydroelectric
Completed Plant
Completed plant cost	4,391	4,307
Accumulated depreciation	1,352	1,288
Net completed plant	3,039	3,019
Other electrical plant
Completed Plant
Completed plant cost	2,068	1,763
Accumulated depreciation	678	737
Net completed plant	1,390	1,026
Multipurpose dams
Completed Plant
Completed plant cost	900	900
Accumulated depreciation	419	413
Net completed plant	481	487
Other stewardship
Completed Plant
Completed plant cost	26	27
Accumulated depreciation	9	9
Net completed plant	$ 17	$ 18

Completed Plant

No definition available.

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- Definition

Period end amount of property, plant and equipment (PPE) related to utility distribution less the cumulative amount of depreciation, depletion and amortization related to PPE that has been recognized in the Income Statement.

+ References

No definition available.

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- Definition

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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-Publisher FASB
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- Definition

Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(8))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
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