Commitments and Contingencies (Details)	3 Months Ended
	Dec. 31, 2017 USD ($) subsidiary	Sep. 30, 2017 USD ($)	Dec. 31, 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	1,750,000
PNG MGP | Environmental Issue
Loss Contingencies [Line Items]
Environmental expenditures cap during year	1,100,000
CPG, PNG and UGI Gas COAs
Loss Contingencies [Line Items]
Accrual for environmental loss contingencies	$ 53,409,000	$ 54,250,000	$ 55,300,000
PNG and CPG
Loss Contingencies [Line Items]
Number of subsidiaries acquired with similar histories | subsidiary	2