Inventories - Components of Inventories (Details) - USD ($) $ in Millions	Jun. 30, 2021	Sep. 30, 2020	Jun. 30, 2020
Inventory
Total inventories	$ 296	$ 241	$ 201
Non-utility LPG and natural gas
Inventory
Total inventories	187	164	135
Gas Utility natural gas
Inventory
Total inventories	16	20	11
Materials, supplies and other
Inventory
Total inventories	$ 93	$ 57	$ 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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