Commitments and Contingencies - Minimum Future Payments Under Operating Leases (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Commitments and Contingencies Disclosure [Abstract]
Aggregate rental expense for leases	$ 99.5	$ 102.0	$ 86.1
Operating Leased Assets [Line Items]
2018	91.0
2019	77.8
2020	69.4
2021	57.2
2022	45.2
After 2022	114.3
AmeriGas Propane
Operating Leased Assets [Line Items]
2018	70.0
2019	61.7
2020	56.5
2021	48.9
2022	40.7
After 2022	110.3
UGI Utilities
Operating Leased Assets [Line Items]
2018	7.5
2019	6.0
2020	4.4
2021	2.7
2022	0.8
After 2022	0.2
UGI International
Operating Leased Assets [Line Items]
2018	11.2
2019	8.1
2020	6.6
2021	4.7
2022	3.2
After 2022	3.2
Other
Operating Leased Assets [Line Items]
2018	2.3
2019	2.0
2020	1.9
2021	0.9
2022	0.5
After 2022	$ 0.6