Revenue from Contracts with Customers - Schedule of Disaggregated Revenues By Reportable Segment (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	$ 7,147	$ 7,045	$ 8,761
Other revenues	140	165	167
Total revenues	7,287	7,210	8,928
Eliminations
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	(350)	(266)	(323)
Other revenues	0	0	(3)
Total revenues	(350)	(266)	(326)
Eliminations | Utilities
Disaggregation of Revenue [Line Items]
Total revenues	80	49	74
Eliminations | Midstream & Marketing
Disaggregation of Revenue [Line Items]
Total revenues	270	217	251
Eliminations | UGI International
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Eliminations | AmeriGas Propane
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Operating Segments | Utilities
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	1,736	1,552	1,816
Other revenues	25	46	38
Total revenues	1,761	1,598	1,854
Operating Segments | Midstream & Marketing
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	1,483	1,368	1,845
Other revenues	0	1	2
Total revenues	1,483	1,369	1,847
Operating Segments | UGI International
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	2,077	2,240	2,927
Other revenues	42	39	38
Total revenues	2,119	2,279	2,965
Operating Segments | AmeriGas Propane
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	2,201	2,193	2,496
Other revenues	75	78	85
Total revenues	2,276	2,271	2,581
Corporate & Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	(42)	0
Other revenues	(2)	1	7
Total revenues	(2)	(41)	7
Total Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	1,656	1,503	1,742
Total Utility | Eliminations
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	(80)	(49)	(74)
Total Utility | Operating Segments | Utilities
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	1,736	1,552	1,816
Total Utility | Operating Segments | Midstream & Marketing
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Total Utility | Operating Segments | UGI International
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Total Utility | Operating Segments | AmeriGas Propane
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Total Utility | Corporate & Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Residential
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	970	873	1,020
Residential | Eliminations
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Residential | Operating Segments | Utilities
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	970	873	1,020
Residential | Operating Segments | Midstream & Marketing
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Residential | Operating Segments | UGI International
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Residential | Operating Segments | AmeriGas Propane
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Residential | Corporate & Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Commercial & Industrial
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	385	344	413
Commercial & Industrial | Eliminations
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Commercial & Industrial | Operating Segments | Utilities
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	385	344	413
Commercial & Industrial | Operating Segments | Midstream & Marketing
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Commercial & Industrial | Operating Segments | UGI International
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Commercial & Industrial | Operating Segments | AmeriGas Propane
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Commercial & Industrial | Corporate & Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Large delivery service
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	196	183	177
Large delivery service | Eliminations
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Large delivery service | Operating Segments | Utilities
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	196	183	177
Large delivery service | Operating Segments | Midstream & Marketing
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Large delivery service | Operating Segments | UGI International
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Large delivery service | Operating Segments | AmeriGas Propane
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Large delivery service | Corporate & Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Off-system sales and capacity releases
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	74	67	89
Off-system sales and capacity releases | Eliminations
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	(79)	(48)	(73)
Off-system sales and capacity releases | Operating Segments | Utilities
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	153	115	162
Off-system sales and capacity releases | Operating Segments | Midstream & Marketing
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Off-system sales and capacity releases | Operating Segments | UGI International
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Off-system sales and capacity releases | Operating Segments | AmeriGas Propane
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Off-system sales and capacity releases | Corporate & Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	31	36	43
Other | Eliminations
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	(1)	(1)	(1)
Other | Operating Segments | Utilities
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	32	37	44
Other | Operating Segments | Midstream & Marketing
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Other | Operating Segments | UGI International
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Other | Operating Segments | AmeriGas Propane
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Other | Corporate & Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Total Non-Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	5,491	5,542	7,019
Total Non-Utility | Eliminations
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	(270)	(217)	(249)
Total Non-Utility | Operating Segments | Utilities
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Total Non-Utility | Operating Segments | Midstream & Marketing
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	1,483	1,368	1,845
Total Non-Utility | Operating Segments | UGI International
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	2,077	2,240	2,927
Total Non-Utility | Operating Segments | AmeriGas Propane
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	2,201	2,193	2,496
Total Non-Utility | Corporate & Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	(42)	0
Retail
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	3,738	3,733	3,952
Retail | Eliminations
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Retail | Operating Segments | Utilities
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Retail | Operating Segments | Midstream & Marketing
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Retail | Operating Segments | UGI International
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	1,785	1,816	1,768
Retail | Operating Segments | AmeriGas Propane
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	1,953	1,917	2,184
Retail | Corporate & Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Wholesale
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	231	270	325
Wholesale | Eliminations
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Wholesale | Operating Segments | Utilities
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Wholesale | Operating Segments | Midstream & Marketing
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Wholesale | Operating Segments | UGI International
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	156	180	207
Wholesale | Operating Segments | AmeriGas Propane
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	75	90	118
Wholesale | Corporate & Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Energy Marketing
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	998	980	2,139
Energy Marketing | Eliminations
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	(159)	(96)	(143)
Energy Marketing | Operating Segments | Utilities
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Energy Marketing | Operating Segments | Midstream & Marketing
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	1,099	948	1,410
Energy Marketing | Operating Segments | UGI International
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	58	170	872
Energy Marketing | Operating Segments | AmeriGas Propane
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Energy Marketing | Corporate & Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	(42)	0
Reduction in revenue		42
Pipeline
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	225	246	251
Pipeline | Eliminations
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Pipeline | Operating Segments | Utilities
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Pipeline | Operating Segments | Midstream & Marketing
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	225	246	251
Pipeline | Operating Segments | UGI International
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Pipeline | Operating Segments | AmeriGas Propane
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Pipeline | Corporate & Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Peaking
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	27	10	31
Peaking | Eliminations
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	(111)	(121)	(106)
Peaking | Operating Segments | Utilities
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Peaking | Operating Segments | Midstream & Marketing
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	138	131	137
Peaking | Operating Segments | UGI International
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Peaking | Operating Segments | AmeriGas Propane
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Peaking | Corporate & Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	21	16	14
Other | Eliminations
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Other | Operating Segments | Utilities
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Other | Operating Segments | Midstream & Marketing
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	21	16	14
Other | Operating Segments | UGI International
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Other | Operating Segments | AmeriGas Propane
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Other | Corporate & Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Electricity Generation
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		27	33
Electricity Generation | Eliminations
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		0	0
Electricity Generation | Operating Segments | Utilities
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		0	0
Electricity Generation | Operating Segments | Midstream & Marketing
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		27	33
Electricity Generation | Operating Segments | UGI International
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		0	0
Electricity Generation | Operating Segments | AmeriGas Propane
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		0	0
Electricity Generation | Corporate & Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		0	0
Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	251	260	274
Other | Eliminations
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Other | Operating Segments | Utilities
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Other | Operating Segments | Midstream & Marketing
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Other | Operating Segments | UGI International
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	78	74	80
Other | Operating Segments | AmeriGas Propane
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	173	186	194
Other | Corporate & Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	$ 0	$ 0	$ 0