Inventories (Details) - USD ($) $ in Millions	Sep. 30, 2022	Sep. 30, 2021
Public Utilities, Inventory
Total inventories	$ 665	$ 469
Non-utility LPG and natural gas
Public Utilities, Inventory
Total inventories	335	278
Gas Utility natural gas
Public Utilities, Inventory
Total inventories	166	68
Energy certificates
Public Utilities, Inventory
Total inventories	70	53
Materials, supplies and other
Public Utilities, Inventory
Total inventories	$ 94	$ 70