Inventories - Narrative (Details) - UGI Utilities $ in Millions	6 Months Ended
	Mar. 31, 2018 storage_agreement Bcf	Sep. 30, 2017 USD ($) Bcf	Mar. 31, 2017 Bcf
Inventory
Number of storage agreements | storage_agreement	5
Volume of gas storage inventories released under SCAAs with non-affiliates (in bcf) | Bcf	0	2.3	0.0
Carrying value of gas storage inventories released under SCAAs with non-affiliates | $		$ 6.7
Maximum
Inventory
SCAA contract term (in years)	3 years