Equity Method Investments - Schedule of Equity Method Investments (Details) - USD ($) $ in Millions	Sep. 30, 2025	Sep. 30, 2024
Schedule of Equity Method Investments [Line Items]
Carrying Value	$ 400	$ 370
Midstream & Marketing
Schedule of Equity Method Investments [Line Items]
Carrying Value	396	359
UGI International
Schedule of Equity Method Investments [Line Items]
Carrying Value	$ 4	10
Aurum Renewables
Schedule of Equity Method Investments [Line Items]
Ownership Interest	40.00%
Aurum Renewables | Midstream & Marketing
Schedule of Equity Method Investments [Line Items]
Carrying Value	$ 46	$ 47
Ownership Interest		40.00%
Pine Run | Midstream & Marketing
Schedule of Equity Method Investments [Line Items]
Carrying Value	$ 101	$ 86
Ownership Interest	49.00%	49.00%
MBL Bioenergy | Midstream & Marketing
Schedule of Equity Method Investments [Line Items]
Carrying Value	$ 222	$ 206
Ownership Interest	99.99%	99.99%
Other | Midstream & Marketing
Schedule of Equity Method Investments [Line Items]
Carrying Value	$ 27	$ 20
Other
Schedule of Equity Method Investments [Line Items]
Carrying Value	$ 0	$ 1