Commitments and Contingencies (Details)	9 Months Ended
	Jun. 30, 2017 USD ($) subsidiary	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)
UGI Gas | Environmental Issue
Loss Contingencies [Line Items]
Environmental expenditures cap during year	$ 2,500,000
CPG MGP | Environmental Issue
Loss Contingencies [Line Items]
Environmental expenditures cap during year	1,800,000
PNG MGP | Environmental Issue
Loss Contingencies [Line Items]
Environmental expenditures cap during year	$ 1,100,000
PNG-COA
Loss Contingencies [Line Items]
Option to termination agreement by either party effective at end of any two-year period beginning with the original effective date in March 2004 (in years)	2 years
CPG, PNG and UGI Gas COAs
Loss Contingencies [Line Items]
Accrual for environmental loss contingencies	$ 55,185,000	$ 55,063,000	$ 56,006,000
PNG and CPG
Loss Contingencies [Line Items]
Number of subsidiaries acquired with similar histories | subsidiary	2