Utility Regulatory Assets and Liabilities and Regulatory Matters - Narrative (Details) - USD ($)								12 Months Ended
	Oct. 08, 2020	Jan. 28, 2020	Oct. 11, 2019	Jan. 28, 2019	Oct. 27, 2018	Oct. 25, 2018	Oct. 19, 2016	Sep. 30, 2020	Sep. 30, 2019
Regulatory Assets [Line Items]
Regulatory asset, amortization period					20 years
UGI Gas
Regulatory Assets [Line Items]
Public utilities, tax benefits, effective period				12 months
Pennsylvania Public Utility Commission | UGI Gas
Regulatory Assets [Line Items]
Public utilities, requested rate increase (decrease), amount		$ 75,000,000		$ 71,000,000
Approved rate increase (decrease), amount			$ 30,000,000
Energy Efficiency and Conservation and Growth extension tariff, extension term			5 years
Tax benefit to be returned				$ 24,000,000
Pennsylvania Public Utility Commission | UGI Gas | Subsequent Event
Regulatory Assets [Line Items]
Regulatory asset, amortization period	10 years
Approved rate increase (decrease), amount	$ 20,000,000
Property, plant and equipment, net threshold	2,875,000,000
Pennsylvania Public Utility Commission | UGI Gas | Beginning January 1, 2021 | Subsequent Event
Regulatory Assets [Line Items]
Approved rate increase (decrease), amount	10,000,000
Pennsylvania Public Utility Commission | UGI Gas | Beginning July 1, 2021 | Subsequent Event
Regulatory Assets [Line Items]
Approved rate increase (decrease), amount	$ 10,000,000
Pennsylvania Public Utility Commission | Electric Utility
Regulatory Assets [Line Items]
Approved rate increase (decrease), amount						$ 3,000,000
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)								$ 8,000,000	$ (2,000,000)
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