Commitments and Contingencies - Contingencies (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017 USD ($) record_of_decision	Sep. 30, 2023 USD ($) subsidiary	Mar. 24, 2023 person	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)
Loss Contingencies [Line Items]
Environmental expenditures cap during year		$ 5
Damage from Fire, Explosion or Other Hazard
Loss Contingencies [Line Items]
Number of fatalities | person			7
Number of injuries | person			11
CPG, PNG and UGI Gas COAs
Loss Contingencies [Line Items]
Accrued liabilities for environmental investigation and remediation costs related to CPG-COA and PNG-COA		$ 52		$ 53
UGI Utilities, Inc. | CPG and PNG
Loss Contingencies [Line Items]
Number of subsidiaries acquired with similar histories | subsidiary		2
AmeriGas OLP | Saranac Lake, New York | New York State Department of Environment Conservation Remediation Plan
Loss Contingencies [Line Items]
Accrued liabilities for environmental investigation and remediation costs related to CPG-COA and PNG-COA				$ 8	$ 8
Number of records of decisions drafted | record_of_decision	3
Estimated remediation plan cost	$ 28