Goodwill and Intangible Assets - Changes in the Carrying Amount of Goodwill (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Goodwill
Balance at beginning of period	$ 3,518	$ 3,456
Acquisitions	261
Dispositions		(5)
Purchase accounting adjustments	1	(2)
Foreign currency translation	(10)	69
Balance at end of period	3,770	3,518
AmeriGas Propane
Goodwill
Balance at beginning of period	2,004	2,004
Acquisitions	0
Dispositions		0
Purchase accounting adjustments	0	0
Foreign currency translation	0	0
Balance at end of period	2,004	2,004
UGI International
Goodwill
Balance at beginning of period	997	930
Acquisitions	6
Dispositions		0
Purchase accounting adjustments	0	(2)
Foreign currency translation	(10)	69
Balance at end of period	993	997
Midstream & Marketing
Goodwill
Balance at beginning of period	335	340
Acquisitions	0
Dispositions		(5)
Purchase accounting adjustments	1	0
Foreign currency translation	0	0
Balance at end of period	336	335
UGI Utilities
Goodwill
Balance at beginning of period	182	182
Acquisitions	255
Dispositions		0
Purchase accounting adjustments	0	0
Foreign currency translation	0	0
Balance at end of period	$ 437	$ 182