Segment Information - Narrative (Details) $ in Millions	3 Months Ended								12 Months Ended
	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Sep. 30, 2019 USD ($) county state segment	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)
Segment Reporting [Abstract]
Number of reportable segments | segment									4
Number of states to which product sale with propane revenue | state									50
Segment Reporting Information
Operating income (loss) | $	$ (99.0)	$ 9.6	$ 538.8	$ 167.7	$ 49.2	$ 29.5	$ 591.0	$ 395.0	$ 617.1	$ 1,064.7	$ 1,010.0
Number of counties									1
UGI Utilities
Segment Reporting Information
Number of counties									2
France | Geographic Concentration Risk | Revenues
Segment Reporting Information
Concentration risk, percentage									20.00%
France | Geographic Concentration Risk | Long-lived Assets
Segment Reporting Information
Concentration risk, percentage									10.00%