Revenue from Contracts with Customers - Schedule of Disaggregation of Revenue By Reportable Segment (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	$ 7,348	$ 6,452	$ 7,211
Other revenues	99	107	109
Total revenues	7,447	6,559	7,320
Negative surcharge			6
Residential
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	568	563	553
Commercial & Industrial
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	218	215	226
Large delivery service
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	148	142	138
Off-system sales and capacity releases
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	51	48	46
Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	21	14	15
Total Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	1,006	982	978
Retail
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	3,957	3,499	4,008
Wholesale
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	328	211	233
Energy Marketing
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	1,564	1,233	1,521
Pipeline
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	181	168	95
Peaking
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	16	6	17
Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	8	7	2
Electricity Generation
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	13	34	43
Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	275	312	314
Total Non-Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	6,342	5,470	6,233
Eliminations
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	(288)	(229)	(302)
Other revenues	(3)	(3)	(4)
Total revenues	(291)	(232)	(306)
Eliminations | Residential
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Eliminations | Commercial & Industrial
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Eliminations | Large delivery service
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Eliminations | Off-system sales and capacity releases
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	(62)	(45)	(65)
Eliminations | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	(2)	(2)	(3)
Eliminations | Total Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	(64)	(47)	(68)
Eliminations | Retail
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Eliminations | Wholesale
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Eliminations | Energy Marketing
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	(126)	(79)	(134)
Eliminations | Pipeline
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Eliminations | Peaking
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	(98)	(100)	(97)
Eliminations | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Eliminations | Electricity Generation
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Eliminations | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	(3)	(3)
Eliminations | Total Non-Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	(224)	(182)	(234)
Eliminations | AmeriGas Propane
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Eliminations | UGI International
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Eliminations | Midstream & Marketing
Disaggregation of Revenue [Line Items]
Total revenues	224	182	235
Eliminations | UGI Utilities
Disaggregation of Revenue [Line Items]
Total revenues	64	47	68
Operating Segments | AmeriGas Propane
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	2,548	2,315	2,618
Other revenues	66	66	64
Total revenues	2,614	2,381	2,682
Operating Segments | AmeriGas Propane | Residential
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Operating Segments | AmeriGas Propane | Commercial & Industrial
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Operating Segments | AmeriGas Propane | Large delivery service
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Operating Segments | AmeriGas Propane | Off-system sales and capacity releases
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Operating Segments | AmeriGas Propane | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Operating Segments | AmeriGas Propane | Total Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Operating Segments | AmeriGas Propane | Retail
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	2,203	2,037	2,341
Operating Segments | AmeriGas Propane | Wholesale
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	139	63	64
Operating Segments | AmeriGas Propane | Energy Marketing
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Operating Segments | AmeriGas Propane | Pipeline
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Operating Segments | AmeriGas Propane | Peaking
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Operating Segments | AmeriGas Propane | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Operating Segments | AmeriGas Propane | Electricity Generation
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Operating Segments | AmeriGas Propane | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	206	215	213
Operating Segments | AmeriGas Propane | Total Non-Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	2,548	2,315	2,618
Operating Segments | UGI International
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	2,617	2,104	2,339
Other revenues	34	23	33
Total revenues	2,651	2,127	2,372
Operating Segments | UGI International | Residential
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Operating Segments | UGI International | Commercial & Industrial
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Operating Segments | UGI International | Large delivery service
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Operating Segments | UGI International | Off-system sales and capacity releases
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Operating Segments | UGI International | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Operating Segments | UGI International | Total Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Operating Segments | UGI International | Retail
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	1,754	1,462	1,667
Operating Segments | UGI International | Wholesale
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	189	148	169
Operating Segments | UGI International | Energy Marketing
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	605	434	448
Operating Segments | UGI International | Pipeline
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Operating Segments | UGI International | Peaking
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Operating Segments | UGI International | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Operating Segments | UGI International | Electricity Generation
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Operating Segments | UGI International | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	69	60	55
Operating Segments | UGI International | Total Non-Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	2,617	2,104	2,339
Operating Segments | Midstream & Marketing
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	1,401	1,233	1,510
Other revenues	5	14	6
Total revenues	1,406	1,247	1,516
Operating Segments | Midstream & Marketing | Residential
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Operating Segments | Midstream & Marketing | Commercial & Industrial
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Operating Segments | Midstream & Marketing | Large delivery service
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Operating Segments | Midstream & Marketing | Off-system sales and capacity releases
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Operating Segments | Midstream & Marketing | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Operating Segments | Midstream & Marketing | Total Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Operating Segments | Midstream & Marketing | Retail
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Operating Segments | Midstream & Marketing | Wholesale
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Operating Segments | Midstream & Marketing | Energy Marketing
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	1,085	878	1,207
Operating Segments | Midstream & Marketing | Pipeline
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	181	168	95
Operating Segments | Midstream & Marketing | Peaking
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	114	106	114
Operating Segments | Midstream & Marketing | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	8	7	2
Operating Segments | Midstream & Marketing | Electricity Generation
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	13	34	43
Operating Segments | Midstream & Marketing | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	40	49
Operating Segments | Midstream & Marketing | Total Non-Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	1,401	1,233	1,510
Operating Segments | UGI Utilities
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	1,070	1,029	1,046
Other revenues	9	1	3
Total revenues	1,079	1,030	1,049
Operating Segments | UGI Utilities | Residential
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	568	563	553
Operating Segments | UGI Utilities | Commercial & Industrial
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	218	215	226
Operating Segments | UGI Utilities | Large delivery service
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	148	142	138
Operating Segments | UGI Utilities | Off-system sales and capacity releases
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	113	93	111
Operating Segments | UGI Utilities | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	23	16	18
Operating Segments | UGI Utilities | Total Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	1,070	1,029	1,046
Operating Segments | UGI Utilities | Retail
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Operating Segments | UGI Utilities | Wholesale
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Operating Segments | UGI Utilities | Energy Marketing
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Operating Segments | UGI Utilities | Pipeline
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Operating Segments | UGI Utilities | Peaking
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Operating Segments | UGI Utilities | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Operating Segments | UGI Utilities | Electricity Generation
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Operating Segments | UGI Utilities | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Operating Segments | UGI Utilities | Total Non-Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Corporate & Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Other revenues	(12)	6	7
Total revenues	(12)	6	7
Corporate & Other | Residential
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Corporate & Other | Commercial & Industrial
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Corporate & Other | Large delivery service
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Corporate & Other | Off-system sales and capacity releases
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Corporate & Other | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Corporate & Other | Total Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Corporate & Other | Retail
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Corporate & Other | Wholesale
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Corporate & Other | Energy Marketing
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Corporate & Other | Pipeline
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Corporate & Other | Peaking
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Corporate & Other | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Corporate & Other | Electricity Generation
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Corporate & Other | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	0	0
Corporate & Other | Total Non-Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	$ 0	$ 0	$ 0