Supplementary Financial Information - Schedule of Inventories by Major Category (Details) - USD ($) $ in Millions	Jun. 30, 2025	Dec. 31, 2024
Inventories by Major Category
Materials and supplies	$ 544	$ 533
Fuel stock	382	403
Natural gas in storage	39	34
Total inventories	$ 965	$ 970

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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Aggregated amount of unprocessed materials to be used in manufacturing or production process and supplies that will be consumed. This amount is net of valuation reserves and adjustments.

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Energy Related Inventory, Natural Gas in Storage, Net of Reserves

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Energy Related Inventory, Other Fossil Fuel, Net of Reserves

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