Inventories, Net Inventories, Net (Details) - USD ($) $ in Millions	Sep. 30, 2025	Sep. 30, 2024
Inventories, Net
Materials and supplies inventory	$ 986	$ 931
Fuel inventory	278	286
Renewable energy certificates/emissions allowance inventory, net	12	11
Allowance for inventory obsolescence	(83)	(73)
Inventories, net	$ 1,193	$ 1,155

Carrying amount as of the balance sheet date of merchandise, goods, commodities, or supplies relating to a source of usable power held for future sale or future use in manufacturing or production process.

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Amount after valuation and LIFO reserves of inventory expected to be sold, or consumed within one year or operating cycle, if longer.

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Gross amount of unprocessed materials to be used in manufacturing or production process and supplies that will be consumed.

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Amount of valuation reserve for inventory.

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Amount, after of valuation reserves and allowances, of inventory, classified as other, expected to be sold, or consumed within one year or operating cycle, if longer.

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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.

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