Revenue from Contracts with Customers - Disaggregation (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	$ 1,903.0	$ 1,975.0
Other revenue	29.0	32.0
Total revenues	1,932.0	2,007.0
Total Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	284.0	314.0
Residential
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	165.0	184.0
Commercial & Industrial
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	60.0	68.0
Large delivery service
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	40.0	41.0
Off-system sales and capacity releases
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	15.0	17.0
Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	4.0	4.0
Total Non-Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	1,619.0	1,661.0
Retail
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	1,055.0	1,094.0
Wholesale
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	59.0	66.0
Energy Marketing
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	380.0	363.0
Pipeline
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	45.0	43.0
Peaking
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	2.0	4.0
Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	2.0	2.0
Electricity Generation
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	4.0	9.0
Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	72.0	80.0
Eliminations
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	(77.0)	(79.0)
Other revenue	(1.0)	(1.0)
Total revenues	(78.0)	(80.0)
Eliminations | Total Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	(15.0)	(15.0)
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	(14.0)	(14.0)
Eliminations | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	(1.0)	(1.0)
Eliminations | Total Non-Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	(62.0)	(64.0)
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	(26.0)	(26.0)
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	(36.0)	(38.0)
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	0.0	0.0
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 & Marketing
Disaggregation of Revenue [Line Items]
Total revenues	(62.0)	(64.0)
Eliminations | UGI Utilities
Disaggregation of Revenue [Line Items]
Total revenues	(15.0)	(15.0)
Operating Segments | AmeriGas Propane
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	647.0	712.0
Other revenue	19.0	18.0
Total revenues	666.0	730.0
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 | 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 Non-Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	647.0	712.0
Operating Segments | AmeriGas Propane | Retail
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	572.0	631.0
Operating Segments | AmeriGas Propane | Wholesale
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	19.0	22.0
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	56.0	59.0
Operating Segments | UGI International
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	694.0	643.0
Other revenue	6.0	8.0
Total revenues	700.0	651.0
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 | 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 Non-Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	694.0	643.0
Operating Segments | UGI International | Retail
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	483.0	463.0
Operating Segments | UGI International | Wholesale
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	40.0	44.0
Operating Segments | UGI International | Energy Marketing
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	155.0	124.0
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	16.0	12.0
Operating Segments | Midstream & Marketing
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	340.0	370.0
Other revenue	1.0	3.0
Total revenues	341.0	373.0
Operating Segments | Midstream & Marketing | Total Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Operating Segments | Midstream & Marketing | Residential
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Operating Segments | Midstream & Marketing | Commercial & Industrial
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Operating Segments | Midstream & Marketing | Large delivery service
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	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	0.0
Operating Segments | Midstream & Marketing | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Operating Segments | Midstream & Marketing | Total Non-Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	340.0	370.0
Operating Segments | Midstream & Marketing | Retail
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Operating Segments | Midstream & Marketing | Wholesale
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Operating Segments | Midstream & Marketing | Energy Marketing
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	251.0	265.0
Operating Segments | Midstream & Marketing | Pipeline
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	45.0	43.0
Operating Segments | Midstream & Marketing | Peaking
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	38.0	42.0
Operating Segments | Midstream & Marketing | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	2.0	2.0
Operating Segments | Midstream & Marketing | Electricity Generation
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	4.0	9.0
Operating Segments | Midstream & Marketing | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	9.0
Operating Segments | UGI Utilities
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	299.0	329.0
Other revenue	1.0	0.0
Total revenues	300.0	329.0
Operating Segments | UGI Utilities | Total Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	299.0	329.0
Operating Segments | UGI Utilities | Residential
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	165.0	184.0
Operating Segments | UGI Utilities | Commercial & Industrial
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	60.0	68.0
Operating Segments | UGI Utilities | Large delivery service
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	40.0	41.0
Operating Segments | UGI Utilities | Off-system sales and capacity releases
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	29.0	31.0
Operating Segments | UGI Utilities | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	5.0	5.0
Operating Segments | UGI Utilities | Total Non-Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
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
Corporate & Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
Other revenue	3.0	4.0
Total revenues	3.0	4.0
Corporate & Other | Total Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.0	0.0
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 Non-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