Revenue from Contracts with Customers - Schedule of Disaggregated Revenues By Reportable Segment (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	$ 7,045	$ 8,761	$ 9,981
Other revenues	165	167	125
Total revenues	7,210	8,928	10,106
Eliminations
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	(266)	(323)	(474)
Other revenues	0	(3)	(3)
Total revenues	(266)	(326)	(477)
Eliminations | Utilities
Disaggregation of Revenue [Line Items]
Total revenues	49	74	105
Eliminations | Midstream & Marketing
Disaggregation of Revenue [Line Items]
Total revenues	217	251	369
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	1,552	1,816	1,615
Other revenues	46	38	5
Total revenues	1,598	1,854	1,620
Operating Segments | Midstream & Marketing
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	1,368	1,845	2,324
Other revenues	1	2	2
Total revenues	1,369	1,847	2,326
Operating Segments | UGI International
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	2,240	2,927	3,652
Other revenues	39	38	34
Total revenues	2,279	2,965	3,686
Operating Segments | AmeriGas Propane
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	2,193	2,496	2,864
Other revenues	78	85	79
Total revenues	2,271	2,581	2,943
Corporate & Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	(42)	0	0
Other revenues	1	7	8
Total revenues	(41)	7	8
Total Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	1,503	1,742	1,510
Total Utility | Eliminations
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	(49)	(74)	(105)
Total Utility | Operating Segments | Utilities
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	1,552	1,816	1,615
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	873	1,020	875
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	873	1,020	875
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	344	413	365
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	344	413	365
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	183	177	171
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	183	177	171
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	67	89	76
Off-system sales and capacity releases | Eliminations
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	(48)	(73)	(104)
Off-system sales and capacity releases | Operating Segments | Utilities
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	115	162	180
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	36	43	23
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	37	44	24
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	5,542	7,019	8,471
Total Non-Utility | Eliminations
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	(217)	(249)	(369)
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	1,368	1,845	2,324
Total Non-Utility | Operating Segments | UGI International
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	2,240	2,927	3,652
Total Non-Utility | Operating Segments | AmeriGas Propane
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	2,193	2,496	2,864
Total Non-Utility | Corporate & Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	(42)	0	0
Retail
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	3,733	3,952	4,436
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	1,816	1,768	1,997
Retail | Operating Segments | AmeriGas Propane
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	1,917	2,184	2,439
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	270	325	496
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	180	207	278
Wholesale | Operating Segments | AmeriGas Propane
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	90	118	218
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	980	2,139	2,951
Energy Marketing | Eliminations
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	(96)	(143)	(264)
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	948	1,410	1,917
Energy Marketing | Operating Segments | UGI International
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	170	872	1,298
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	(42)	0	0
Reduction in revenue	42
Pipeline
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	246	251	211
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	246	251	211
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	10	31	48
Peaking | Eliminations
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	(121)	(106)	(105)
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	131	137	153
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	16	14	9
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	16	14	9
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	34
Electricity Generation | Eliminations
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Electricity Generation | Operating Segments | Utilities
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Electricity Generation | Operating Segments | Midstream & Marketing
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	27	33	34
Electricity Generation | Operating Segments | UGI International
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Electricity Generation | Operating Segments | AmeriGas Propane
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Electricity Generation | 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	260	274	286
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	74	80	79
Other | Operating Segments | AmeriGas Propane
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	186	194	207
Other | Corporate & Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	$ 0	$ 0	$ 0