Equity Method Investments - Schedule of Equity Method Investments (Details) - USD ($) $ in Millions	Jun. 30, 2024	Sep. 30, 2023	Jun. 30, 2023
Schedule of Equity Method Investments [Line Items]
Carrying Value	$ 349	$ 299	$ 252
Midstream & Marketing
Schedule of Equity Method Investments [Line Items]
Carrying Value	339	264	217
Midstream & Marketing | Aurum Renewables
Schedule of Equity Method Investments [Line Items]
Carrying Value	$ 46	$ 45	$ 31
Ownership Interest	40.00%	40.00%	40.00%
Midstream & Marketing | Pine Run
Schedule of Equity Method Investments [Line Items]
Carrying Value	$ 83	$ 77	$ 75
Ownership Interest	49.00%	49.00%	49.00%
Midstream & Marketing | MBL Bioenergy
Schedule of Equity Method Investments [Line Items]
Carrying Value	$ 190	$ 122	$ 93
Ownership Interest	99.99%	99.99%	99.99%
Midstream & Marketing | Other
Schedule of Equity Method Investments [Line Items]
Carrying Value	$ 20	$ 20	$ 18
UGI International
Schedule of Equity Method Investments [Line Items]
Carrying Value	$ 10	$ 35	$ 35