Revenue from Contracts with Customers Revenue From Contracts with Customers - Disaggregation (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	May 17, 2018
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 2,175.2
Other revenue	25.0
Revenues	2,200.2	$ 2,125.2
Negative surcharge			$ (4.1)
Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	175.7
Commercial & Industrial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	67.6
Large delivery service
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	39.5
Off-system sales and capacity releases
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	15.2
Other (b)
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.5
Total Utility
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	298.5
Retail
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,229.7
Wholesale
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	60.0
Energy Marketing
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	468.9
Pipeline
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	19.4
Peaking
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	2.0
Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1.0
Electricity Generation
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	11.7
Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	84.0
Total Non-Utility
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,876.7
Eliminations
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	(110.5)
Other revenue	(1.1)
Revenues	(111.6)	(97.1)
Eliminations | Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Eliminations | Commercial & Industrial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Eliminations | Large delivery service
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Eliminations | Off-system sales and capacity releases
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	(22.9)
Eliminations | Other (b)
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	(0.7)
Eliminations | Total Utility
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	(23.6)
Eliminations | Retail
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Eliminations | Wholesale
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Eliminations | Energy Marketing
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	(47.5)
Eliminations | Pipeline
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Eliminations | Peaking
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	(38.7)
Eliminations | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Eliminations | Electricity Generation
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Eliminations | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	(0.7)
Eliminations | Total Non-Utility
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	(86.9)
Eliminations | AmeriGas Propane
Disaggregation of Revenue [Line Items]
Revenues	0.0	0.0
Eliminations | UGI International
Disaggregation of Revenue [Line Items]
Revenues	0.0	0.0
Eliminations | Midstream and Marketing
Disaggregation of Revenue [Line Items]
Revenues	86.9	78.2
Eliminations | UGI Utilities
Disaggregation of Revenue [Line Items]
Revenues	23.6	17.7
Operating Segments | AmeriGas Propane
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	803.5
Other revenue	16.7
Revenues	820.2	787.3
Operating Segments | AmeriGas Propane | Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Operating Segments | AmeriGas Propane | Commercial & Industrial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Operating Segments | AmeriGas Propane | Large delivery service
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Operating Segments | AmeriGas Propane | Off-system sales and capacity releases
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Operating Segments | AmeriGas Propane | Other (b)
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Operating Segments | AmeriGas Propane | Total Utility
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Operating Segments | AmeriGas Propane | Retail
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	721.9
Operating Segments | AmeriGas Propane | Wholesale
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	21.0
Operating Segments | AmeriGas Propane | Energy Marketing
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Operating Segments | AmeriGas Propane | Pipeline
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Operating Segments | AmeriGas Propane | Peaking
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Operating Segments | AmeriGas Propane | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Operating Segments | AmeriGas Propane | Electricity Generation
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Operating Segments | AmeriGas Propane | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	60.6
Operating Segments | AmeriGas Propane | Total Non-Utility
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	803.5
Operating Segments | UGI International
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	702.3
Other revenue	8.4
Revenues	710.7	784.2
Operating Segments | UGI International | Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Operating Segments | UGI International | Commercial & Industrial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Operating Segments | UGI International | Large delivery service
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Operating Segments | UGI International | Off-system sales and capacity releases
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Operating Segments | UGI International | Other (b)
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Operating Segments | UGI International | Total Utility
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Operating Segments | UGI International | Retail
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	507.8
Operating Segments | UGI International | Wholesale
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	39.0
Operating Segments | UGI International | Energy Marketing
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	143.1
Operating Segments | UGI International | Pipeline
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Operating Segments | UGI International | Peaking
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Operating Segments | UGI International | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Operating Segments | UGI International | Electricity Generation
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Operating Segments | UGI International | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	12.4
Operating Segments | UGI International | Total Non-Utility
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	702.3
Operating Segments | Midstream and Marketing
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	457.8
Other revenue	1.6
Revenues	459.4	249.8
Operating Segments | Midstream and Marketing | Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Operating Segments | Midstream and Marketing | Commercial & Industrial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Operating Segments | Midstream and Marketing | Large delivery service
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Operating Segments | Midstream and Marketing | Off-system sales and capacity releases
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Operating Segments | Midstream and Marketing | Other (b)
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Operating Segments | Midstream and Marketing | Total Utility
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Operating Segments | Midstream and Marketing | Retail
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Operating Segments | Midstream and Marketing | Wholesale
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Operating Segments | Midstream and Marketing | Energy Marketing
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	373.3
Operating Segments | Midstream and Marketing | Pipeline
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	19.4
Operating Segments | Midstream and Marketing | Peaking
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	40.7
Operating Segments | Midstream and Marketing | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1.0
Operating Segments | Midstream and Marketing | Electricity Generation
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	11.7
Operating Segments | Midstream and Marketing | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	11.7
Operating Segments | Midstream and Marketing | Total Non-Utility
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	457.8
Operating Segments | UGI Utilities
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	322.1
Other revenue	0.6
Revenues	322.7	305.4
Operating Segments | UGI Utilities | Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	175.7
Operating Segments | UGI Utilities | Commercial & Industrial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	67.6
Operating Segments | UGI Utilities | Large delivery service
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	39.5
Operating Segments | UGI Utilities | Off-system sales and capacity releases
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	38.1
Operating Segments | UGI Utilities | Other (b)
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1.2
Operating Segments | UGI Utilities | Total Utility
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	322.1
Operating Segments | UGI Utilities | Retail
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Operating Segments | UGI Utilities | Wholesale
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Operating Segments | UGI Utilities | Energy Marketing
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Operating Segments | UGI Utilities | Pipeline
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Operating Segments | UGI Utilities | Peaking
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Operating Segments | UGI Utilities | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Operating Segments | UGI Utilities | Electricity Generation
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Operating Segments | UGI Utilities | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Operating Segments | UGI Utilities | Total Non-Utility
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Corporate & Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Other revenue	(1.2)
Revenues	(1.2)	$ (1.5)
Corporate & Other | Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Corporate & Other | Commercial & Industrial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Corporate & Other | Large delivery service
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Corporate & Other | Off-system sales and capacity releases
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Corporate & Other | Other (b)
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Corporate & Other | Total Utility
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Corporate & Other | Retail
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Corporate & Other | Wholesale
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Corporate & Other | Energy Marketing
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Corporate & Other | Pipeline
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Corporate & Other | Peaking
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Corporate & Other | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Corporate & Other | Electricity Generation
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Corporate & Other | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0.0
Corporate & Other | Total Non-Utility
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 0.0