Revenue from Contracts with Customers - Disaggregation (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	$ 1,331.8		$ 6,084.5
Other revenue	31.9		85.5
Total revenues	1,363.7	$ 1,440.9	6,170.0	$ 6,378.1
Negative surcharge	(3.3)		11.3
Residential
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	78.1		494.1
Commercial & Industrial
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	34.2		202.5
Large delivery service
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	27.8		111.4
Off-system sales and capacity releases
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	4.0		41.1
Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	8.3		5.5
Total Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	152.4		854.6
Retail
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	754.1		3,389.4
Wholesale
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	44.5		198.3
Energy Marketing
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	274.8		1,295.8
Pipeline
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	17.6		59.4
Peaking
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	3.2		13.3
Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.1		1.8
Electricity Generation
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	8.9		32.2
Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	76.2		239.7
Total Non-Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	1,179.4		5,229.9
Eliminations
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	(38.9)		(273.5)
Other revenue	(0.7)		(2.5)
Total revenues	(39.6)	(44.4)	(276.0)	(330.4)
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	(10.1)		(57.5)
Eliminations | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	(0.8)		(2.3)
Eliminations | Total Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	(10.9)		(59.8)
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	(23.7)		(117.6)
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	(3.2)		(93.6)
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	(1.1)		(2.5)
Eliminations | Total Non-Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	(28.0)		(213.7)
Eliminations | AmeriGas Propane
Disaggregation of Revenue [Line Items]
Total revenues	0.0	0.0	0.0	0.0
Eliminations | UGI International
Disaggregation of Revenue [Line Items]
Total revenues	0.0	0.0	0.0	0.0
Eliminations | Midstream and Marketing
Disaggregation of Revenue [Line Items]
Total revenues	28.0	34.2	213.7	241.4
Eliminations | UGI Utilities
Disaggregation of Revenue [Line Items]
Total revenues	10.9	9.6	59.8	86.0
Operating Segments | AmeriGas Propane
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	462.9		2,223.3
Other revenue	15.8		47.2
Total revenues	478.7	528.4	2,270.5	2,356.0
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 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	405.9		2,002.4
Operating Segments | AmeriGas Propane | Wholesale
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	8.8		55.0
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	48.2		165.9
Operating Segments | AmeriGas Propane | Total Non-Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	462.9		2,223.3
Operating Segments | UGI International
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	478.9		1,956.2
Other revenue	7.7		24.3
Total revenues	486.6	$ 533.6	1,980.5	$ 2,227.4
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	348.2		1,387.0
Operating Segments | UGI International | Wholesale
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	35.7		143.3
Operating Segments | UGI International | Energy Marketing
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	80.4		386.2
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	14.6		39.7
Operating Segments | UGI International | Total Non-Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	478.9		1,956.2
Operating Segments | Midstream and Marketing
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	265.6		1,264.1
Other revenue	1.7		5.0
Total revenues	267.3		1,269.1
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	218.1		1,027.2
Operating Segments | Midstream and Marketing | Pipeline
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	17.6		59.4
Operating Segments | Midstream and Marketing | Peaking
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	6.4		106.9
Operating Segments | Midstream and Marketing | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.1		1.8
Operating Segments | Midstream and Marketing | Electricity Generation
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	8.9		32.2
Operating Segments | Midstream and Marketing | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	14.5		36.6
Operating Segments | Midstream and Marketing | Total Non-Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	265.6		1,264.1
Operating Segments | UGI Utilities
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	163.3		914.4
Other revenue	0.6		1.8
Total revenues	163.9		916.2
Operating Segments | UGI Utilities | Residential
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	78.1		494.1
Operating Segments | UGI Utilities | Commercial & Industrial
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	34.2		202.5
Operating Segments | UGI Utilities | Large delivery service
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	27.8		111.4
Operating Segments | UGI Utilities | Off-system sales and capacity releases
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	14.1		98.6
Operating Segments | UGI Utilities | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	9.1		7.8
Operating Segments | UGI Utilities | Total Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	163.3		914.4
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	6.8		9.7
Total revenues	6.8		9.7
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