Commitments and Contingencies (Details)		6 Months Ended	12 Months Ended			20 Months Ended
	Nov. 07, 2017	Mar. 31, 2019 USD ($) subsidiary	Dec. 31, 2017 record_of_decision	Dec. 31, 2008 lb	Dec. 31, 2007 lb	Jul. 01, 2019 USD ($)	Sep. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)
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		5,400,000
CPG, PNG and UGI Gas COAs
Loss Contingencies
Accrual for environmental loss contingencies		$ 50,800,000					$ 51,000,000	$ 51,900,000
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
Loss contingency, number of remediation plans | record_of_decision			3
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