Debt - Schedule of Long-term Debt (Footnotes) (Details) - USD ($)	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Debt Instrument [Line Items]
Long-term debt	$ 6,600,000,000	$ 6,632,000,000
Senior Secured Notes | Mountaineer senior notes
Debt Instrument [Line Items]
Long-term debt		180,000,000
Unamortized premium	$ 19,000,000	21,000,000
Senior Secured Notes | Mountaineer senior notes | Minimum
Debt Instrument [Line Items]
Interest rate	3.50%
Senior Secured Notes | Mountaineer senior notes | Maximum
Debt Instrument [Line Items]
Interest rate	4.49%
UGI International
Debt Instrument [Line Items]
Fixed rate	3.10%
Long-term debt	$ 739,000,000	$ 682,000,000
UGI International | Term Loan | Variable-rate term loan
Debt Instrument [Line Items]
Effective interest rate (as a percentage)		1.89%
UGI International | UGI Utilities Senior Notes: | 2.50% Senior Notes due December 2029
Debt Instrument [Line Items]
Effective interest rate (as a percentage)	4.95%
Interest rate	2.50%
Midstream & Marketing
Debt Instrument [Line Items]
Fixed rate	4.53%
Long-term debt	$ 820,000,000	$ 710,000,000
Midstream & Marketing | Term Loan | Variable-rate term loan
Debt Instrument [Line Items]
Effective interest rate (as a percentage)	7.82%	5.13%
Quarterly Installments	$ 2,000,000
Utilities
Debt Instrument [Line Items]
Long-term debt	$ 1,649,000,000	$ 1,656,000,000
Utilities | Variable-rate term loan
Debt Instrument [Line Items]
Fixed rate	2.82%
Utilities | Term Loan | Variable-rate term loan
Debt Instrument [Line Items]
Effective interest rate (as a percentage)	3.92%	3.92%
Quarterly Installments	$ 2,000,000
UGI Corporation
Debt Instrument [Line Items]
Long-term debt	$ 1,007,000,000	$ 1,015,000,000
UGI Corporation | 3-year Term loan
Debt Instrument [Line Items]
Fixed rate	0.70%
UGI Corporation | 7-Year Term Loan
Debt Instrument [Line Items]
Fixed rate	0.70%
UGI Corporation | Term Loan | 3-year Term loan
Debt Instrument [Line Items]
Effective interest rate (as a percentage)	2.77%	2.67%
UGI Corporation | Term Loan | 5-year Term Loan
Debt Instrument [Line Items]
Effective interest rate (as a percentage)	7.79%	4.15%
Quarterly Installments	$ 9,000,000
UGI Corporation | Term Loan | 7-Year Term Loan
Debt Instrument [Line Items]
Effective interest rate (as a percentage)	4.73%	3.53%
UGI Corporation | Line of Credit
Debt Instrument [Line Items]
Effective interest rate (as a percentage)	7.80%	5.61%