Inventories - Narrative (Details) - UGI Utilities $ in Millions	3 Months Ended
	Dec. 31, 2017 USD ($) storage_agreement Bcf	Sep. 30, 2017 USD ($) Bcf	Dec. 31, 2016 USD ($) Bcf
Inventory
Number of storage agreements | storage_agreement	5
Volume of gas storage inventories released under SCAAs with non-affiliates (in bcf) | Bcf	1.8	2.3	1.9
Carrying value of gas storage inventories released under SCAAs with non-affiliates | $	$ 5.1	$ 6.7	$ 4.8
Maximum
Inventory
SCAA contract term (in years)	3 years