Revenue from Contracts with Customers Revenue From Contracts with Customers - Disaggregation (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	$ 2,577.5		$ 4,752.7
Other revenue	28.6		53.6
Total revenues	2,606.1	$ 2,812.0	4,806.3	$ 4,937.2
Negative surcharge	(10.5)		(14.6)
Residential
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	240.3		416.0
Commercial & Industrial
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	100.7		168.3
Large delivery service
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	44.1		83.6
Off-system sales and capacity releases
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	21.9		37.1
Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	(3.3)		(2.8)
Total Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	403.7		702.2
Retail
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	1,405.6		2,635.3
Wholesale
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	93.8		153.8
Energy Marketing
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	552.1		1,021.0
Pipeline
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	22.4		41.8
Peaking
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	8.1		10.1
Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.7		1.7
Electricity Generation
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	11.6		23.3
Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	79.5		163.5
Total Non-Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	2,173.8		4,050.5
Eliminations
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	(124.1)		(234.6)
Other revenue	(0.7)		(1.8)
Total revenues	(124.8)	(188.9)	(236.4)	(286.0)
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	(24.5)		(47.4)
Eliminations | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	(0.8)		(1.5)
Eliminations | Total Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	(25.3)		(48.9)
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	(46.4)		(93.9)
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	(51.7)		(90.4)
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	(0.7)		(1.4)
Eliminations | Total Non-Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	(98.8)		(185.7)
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	98.8	129.0	185.7	207.2
Eliminations | UGI Utilities
Disaggregation of Revenue [Line Items]
Total revenues	25.3	58.7	48.9	76.4
Operating Segments | AmeriGas Propane
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	956.9		1,760.4
Other revenue	14.7		31.4
Total revenues	971.6	1,040.3	1,791.8	1,827.6
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	874.6		1,596.5
Operating Segments | AmeriGas Propane | Wholesale
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	25.2		46.2
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	57.1		117.7
Operating Segments | AmeriGas Propane | Total Non-Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	956.9		1,760.4
Operating Segments | UGI International
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	775.0		1,477.3
Other revenue	8.2		16.6
Total revenues	783.2	$ 909.6	1,493.9	$ 1,693.8
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	531.0		1,038.8
Operating Segments | UGI International | Wholesale
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	68.6		107.6
Operating Segments | UGI International | Energy Marketing
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	162.7		305.8
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	12.7		25.1
Operating Segments | UGI International | Total Non-Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	775.0		1,477.3
Operating Segments | Midstream and Marketing
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	540.7		998.5
Other revenue	1.7		3.3
Total revenues	542.4		1,001.8
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	435.8		809.1
Operating Segments | Midstream and Marketing | Pipeline
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	22.4		41.8
Operating Segments | Midstream and Marketing | Peaking
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	59.8		100.5
Operating Segments | Midstream and Marketing | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0.7		1.7
Operating Segments | Midstream and Marketing | Electricity Generation
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	11.6		23.3
Operating Segments | Midstream and Marketing | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	10.4		22.1
Operating Segments | Midstream and Marketing | Total Non-Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	540.7		998.5
Operating Segments | UGI Utilities
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	429.0		751.1
Other revenue	0.6		1.2
Total revenues	429.6		752.3
Operating Segments | UGI Utilities | Residential
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	240.3		416.0
Operating Segments | UGI Utilities | Commercial & Industrial
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	100.7		168.3
Operating Segments | UGI Utilities | Large delivery service
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	44.1		83.6
Operating Segments | UGI Utilities | Off-system sales and capacity releases
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	46.4		84.5
Operating Segments | UGI Utilities | Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	(2.5)		(1.3)
Operating Segments | UGI Utilities | Total Utility
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	429.0		751.1
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	4.1		2.9
Total revenues	4.1		2.9
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