Commitments and Contingencies (Details)	3 Months Ended	12 Months Ended
	Dec. 31, 2020 USD ($) subsidiary	Dec. 31, 2017 USD ($) record_of_decision	Dec. 31, 2008 lb	Dec. 31, 2007 lb	Sep. 30, 2020 USD ($)	Dec. 31, 2019 USD ($)
Loss Contingencies
Environmental expenditures cap during calendar year	$ 5,000,000
Amount of propane in cylinders before reduction (in pounds) | lb				17
Amount of propane in cylinders after reduction (in pounds) | lb			15
CPG, PNG and UGI Gas COAs
Loss Contingencies
Accrual for environmental loss contingencies	$ 49,000,000				$ 53,000,000	$ 50,000,000
UGI Utilities | PNG and CPG
Loss Contingencies
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
Accrual for environmental loss contingencies	$ 8,000,000
Loss contingency, number of remediation plans | record_of_decision		3
Estimated remediation plan cost		$ 28,000,000