Commitments and Contingencies (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017 record_of_decision	Dec. 31, 2008 lb	Dec. 31, 2007 lb	Dec. 31, 2019 USD ($) subsidiary	Sep. 30, 2019 USD ($)	Dec. 31, 2018 USD ($)	Sep. 30, 2017 USD ($)
Loss Contingencies
Environmental expenditures cap during calendar year				$ 5.4
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				$ 49.5	$ 50.4	$ 50.5
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				$ 7.5
Loss contingency, number of remediation plans | record_of_decision	3
Estimated remediation plan cost							$ 27.7