Commitments and Contingencies (Details)		9 Months Ended	20 Months Ended
	Nov. 07, 2017	Jun. 30, 2018 USD ($) subsidiary lb	Jul. 01, 2019 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)
Loss Contingencies
Capital contributions		$ 0
Amount of propane in cylinders before reduction (in pounds) | lb		17
Amount of propane in cylinders after reduction (in pounds) | lb		15
UGI Gas | Environmental Matters
Loss Contingencies
Environmental expenditures cap during calendar year		$ 2,500,000
CPG MGP | Environmental Matters
Loss Contingencies
Environmental expenditures cap during calendar year		1,800,000
PNG MGP | Environmental Matters
Loss Contingencies
Environmental expenditures cap during calendar year		1,100,000
CPG, PNG and UGI Gas COAs
Loss Contingencies
Accrual for environmental loss contingencies		$ 52,200,000		$ 54,300,000	$ 55,200,000
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					$ 7,500,000
Estimated remediation plan cost						$ 27,700,000
Capital Unit, Class B
Loss Contingencies
Weighted average price of common units, volume, period	20 days
Basis spread on dividend yield	1.30%
Conversion of stock, period subsequent to initial issuance, election one	5 years
Conversion of stock, conversion ratio	1
Conversion of stock, period subsequent to initial issuance, election two	6 years
Minimum | Capital Unit, Class B
Loss Contingencies
Conversion of stock, closing trading price, percentage	110.00%
Forecast
Loss Contingencies
Capital contributions			$ 225,000,000