Inventories - Components of Inventories (Details) - USD ($) $ in Millions	Mar. 31, 2022	Sep. 30, 2021	Mar. 31, 2021
Inventory
Total inventories	$ 398	$ 469	$ 268
Non-utility LPG and natural gas
Inventory
Total inventories	253	278	179
Gas Utility natural gas
Inventory
Total inventories	6	68	3
Energy certificates
Inventory
Total inventories	63	53	31
Materials, supplies and other
Inventory
Total inventories	$ 76	$ 70	$ 55

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

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Publisher FASB
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