Utility Regulatory Assets and Liabilities and Regulatory Matters - Narrative (Details) - USD ($) $ in Millions									6 Months Ended	12 Months Ended
	Oct. 11, 2019	Jan. 28, 2019	Oct. 27, 2018	Oct. 25, 2018	May 17, 2018	Jan. 26, 2018	Jun. 30, 2017	Oct. 19, 2016	Jun. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Regulatory Assets [Line Items]
Regulatory asset, amortization period			20 years
UGI South
Regulatory Assets [Line Items]
PUC temporary rates order, percent of reduction in base rate revenues					4.71%
UGI North
Regulatory Assets [Line Items]
PUC temporary rates order, percent of reduction in base rate revenues					2.87%
UGI Central
Regulatory Assets [Line Items]
PUC temporary rates order, percent of reduction in base rate revenues					6.34%
Pennsylvania Public Utility Commission | UGI Gas
Regulatory Assets [Line Items]
Requested operating revenue increase		$ 71.1
Proposed negative surcharge		4.50%
Tax benefit to be returned									$ 24.0
Pennsylvania Public Utility Commission | Electric Utility
Regulatory Assets [Line Items]
Requested operating revenue increase				$ 3.2		$ 7.7
Requested annual base distribution revenue increase						$ 9.2
Tax Cuts and Jobs Act Of 2017, customer billing credit			$ 0.2
Pennsylvania Public Utility Commission | PNG
Regulatory Assets [Line Items]
Base distribution rate increase							$ 11.3
Postretirement benefit overcollections
Regulatory Assets [Line Items]
Regulatory liability, amortization period								10 years
Gas Utility
Regulatory Assets [Line Items]
Fair value of unrealized gains (losses)										$ (2.2)	$ 2.9
Minimum
Regulatory Assets [Line Items]
Average remaining depreciable lives of the associated property										1 year
Maximum
Regulatory Assets [Line Items]
Average remaining depreciable lives of the associated property										65 years
Maximum | Removal Costs, Net
Regulatory Assets [Line Items]
Regulatory asset, amortization period										5 years
Subsequent Event | Pennsylvania Public Utility Commission | UGI Gas
Regulatory Assets [Line Items]
Energy Efficiency and Conservation and Growth extension tariff, extension term	5 years
Base distribution rate increase	$ 30.0