Revenue from Contracts with Customers - Disaggregation (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	$ 1,975.8	$ 2,175.2
Other revenue	30.8	25.0
Total revenues	2,006.6	2,200.2
Negative surcharge		4.1
Residential
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	184.1	175.7
Commercial & Industrial
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	67.9	67.6
Large delivery service
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	41.3	39.5
Off-system sales and capacity releases
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	16.4	15.2
Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	4.4	0.5
Total Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	314.1	298.5
Retail
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	1,094.4	1,229.7
Wholesale
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	65.8	60.0
Energy Marketing
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	362.9	468.9
Pipeline
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	43.2	19.4
Peaking
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	3.9	2.0
Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	1.8	1.0
Electricity Generation
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	8.8	11.7
Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	80.9	84.0
Total Non-Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	1,661.7	1,876.7
Eliminations
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	(78.9)	(110.5)
Other revenue	(0.8)	(1.1)
Total revenues	(79.7)	(111.6)
Eliminations | Residential
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Eliminations | Commercial & Industrial
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Eliminations | Large delivery service
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Eliminations | Off-system sales and capacity releases
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	(14.1)	(22.9)
Eliminations | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	(0.6)	(0.7)
Eliminations | Total Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	(14.7)	(23.6)
Eliminations | Retail
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Eliminations | Wholesale
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Eliminations | Energy Marketing
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	(25.6)	(47.5)
Eliminations | Pipeline
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Eliminations | Peaking
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	(37.7)	(38.7)
Eliminations | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Eliminations | Electricity Generation
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Eliminations | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	(0.9)	(0.7)
Eliminations | Total Non-Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	(64.2)	(86.9)
Eliminations | AmeriGas Propane
Disaggregation of Revenue [Line Items]
Total revenues	0.0	0.0
Eliminations | UGI International
Disaggregation of Revenue [Line Items]
Total revenues	0.0	0.0
Eliminations | Midstream and Marketing
Disaggregation of Revenue [Line Items]
Total revenues	64.2	86.9
Eliminations | UGI Utilities
Disaggregation of Revenue [Line Items]
Total revenues	14.7	23.6
Operating Segments | AmeriGas Propane
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	712.4	803.5
Other revenue	18.0	16.7
Total revenues	730.4	820.2
Operating Segments | AmeriGas Propane | Residential
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Operating Segments | AmeriGas Propane | Commercial & Industrial
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Operating Segments | AmeriGas Propane | Large delivery service
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	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	0.0
Operating Segments | AmeriGas Propane | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Operating Segments | AmeriGas Propane | Total Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Operating Segments | AmeriGas Propane | Retail
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	631.2	721.9
Operating Segments | AmeriGas Propane | Wholesale
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	22.0	21.0
Operating Segments | AmeriGas Propane | Energy Marketing
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Operating Segments | AmeriGas Propane | Pipeline
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Operating Segments | AmeriGas Propane | Peaking
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Operating Segments | AmeriGas Propane | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Operating Segments | AmeriGas Propane | Electricity Generation
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Operating Segments | AmeriGas Propane | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	59.2	60.6
Operating Segments | AmeriGas Propane | Total Non-Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	712.4	803.5
Operating Segments | UGI International
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	643.2	702.3
Other revenue	8.2	8.4
Total revenues	651.4	710.7
Operating Segments | UGI International | Residential
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Operating Segments | UGI International | Commercial & Industrial
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Operating Segments | UGI International | Large delivery service
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	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	0.0
Operating Segments | UGI International | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Operating Segments | UGI International | Total Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Operating Segments | UGI International | Retail
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	463.2	507.8
Operating Segments | UGI International | Wholesale
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	43.8	39.0
Operating Segments | UGI International | Energy Marketing
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	123.9	143.1
Operating Segments | UGI International | Pipeline
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Operating Segments | UGI International | Peaking
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Operating Segments | UGI International | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Operating Segments | UGI International | Electricity Generation
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Operating Segments | UGI International | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	12.3	12.4
Operating Segments | UGI International | Total Non-Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	643.2	702.3
Operating Segments | Midstream and Marketing
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	370.3	457.8
Other revenue	2.2	1.6
Total revenues	372.5	459.4
Operating Segments | Midstream and Marketing | Residential
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Operating Segments | Midstream and Marketing | Commercial & Industrial
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Operating Segments | Midstream and Marketing | Large delivery service
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Operating Segments | Midstream and Marketing | Off-system sales and capacity releases
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Operating Segments | Midstream and Marketing | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Operating Segments | Midstream and Marketing | Total Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Operating Segments | Midstream and Marketing | Retail
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Operating Segments | Midstream and Marketing | Wholesale
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Operating Segments | Midstream and Marketing | Energy Marketing
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	264.6	373.3
Operating Segments | Midstream and Marketing | Pipeline
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	43.2	19.4
Operating Segments | Midstream and Marketing | Peaking
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	41.6	40.7
Operating Segments | Midstream and Marketing | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	1.8	1.0
Operating Segments | Midstream and Marketing | Electricity Generation
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	8.8	11.7
Operating Segments | Midstream and Marketing | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	10.3	11.7
Operating Segments | Midstream and Marketing | Total Non-Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	370.3	457.8
Operating Segments | UGI Utilities
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	328.8	322.1
Other revenue	0.5	0.6
Total revenues	329.3	322.7
Operating Segments | UGI Utilities | Residential
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	184.1	175.7
Operating Segments | UGI Utilities | Commercial & Industrial
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	67.9	67.6
Operating Segments | UGI Utilities | Large delivery service
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	41.3	39.5
Operating Segments | UGI Utilities | Off-system sales and capacity releases
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	30.5	38.1
Operating Segments | UGI Utilities | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	5.0	1.2
Operating Segments | UGI Utilities | Total Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	328.8	322.1
Operating Segments | UGI Utilities | Retail
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Operating Segments | UGI Utilities | Wholesale
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Operating Segments | UGI Utilities | Energy Marketing
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Operating Segments | UGI Utilities | Pipeline
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Operating Segments | UGI Utilities | Peaking
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Operating Segments | UGI Utilities | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Operating Segments | UGI Utilities | Electricity Generation
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Operating Segments | UGI Utilities | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Operating Segments | UGI Utilities | Total Non-Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Corporate & Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Other revenue	2.7	(1.2)
Total revenues	2.7	(1.2)
Corporate & Other | Residential
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Corporate & Other | Commercial & Industrial
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Corporate & Other | Large delivery service
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Corporate & Other | Off-system sales and capacity releases
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Corporate & Other | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Corporate & Other | Total Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Corporate & Other | Retail
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Corporate & Other | Wholesale
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Corporate & Other | Energy Marketing
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Corporate & Other | Pipeline
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Corporate & Other | Peaking
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Corporate & Other | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Corporate & Other | Electricity Generation
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Corporate & Other | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Corporate & Other | Total Non-Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	$ 0.0	$ 0.0