Equity Method Investments - Schedule of Equity Method Investments (Details) - USD ($) $ in Millions	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Schedule of Equity Method Investments [Line Items]
Carrying Value	$ 299	$ 130	$ 174
Aurum Renewables
Schedule of Equity Method Investments [Line Items]
Ownership Interest	40.00%
Midstream & Marketing
Schedule of Equity Method Investments [Line Items]
Carrying Value	$ 264	109
Midstream & Marketing | Aurum Renewables
Schedule of Equity Method Investments [Line Items]
Carrying Value	45	0
Midstream & Marketing | Pine Run
Schedule of Equity Method Investments [Line Items]
Carrying Value	$ 77	$ 68
Ownership Interest	49.00%	49.00%
Midstream & Marketing | MBL Bioenergy
Schedule of Equity Method Investments [Line Items]
Carrying Value	$ 122	$ 23
Ownership Interest	99.99%	99.99%
Midstream & Marketing | Other
Schedule of Equity Method Investments [Line Items]
Carrying Value	$ 20	$ 18
UGI International
Schedule of Equity Method Investments [Line Items]
Carrying Value	$ 35	$ 21