Segment Information - Schedule of Segment Reporting Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Sep. 30, 2021
Segment Reporting Information [Line Items]
Revenues from external customers	$ 2,033	$ 1,496	$ 8,172	$ 6,009
Cost of sales	1,361	516	4,951	2,623
Operating income	99	391	1,363	1,564
(Loss) income from equity investees	(45)	(86)	(32)	(69)
Loss on extinguishment of debt	0	0	(11)	0
Other non-operating income (expense), net	20	1	41	0
Earnings before interest expense and income taxes	74	306	1,361	1,495
Interest expense	(82)	(77)	(245)	(233)
(Loss) income before income taxes	(8)	229	1,116	1,262
Depreciation and amortization	130	125	387	375
Capital expenditures (including the effects of accruals)	201	162	546	438
Total assets	17,111	15,006	17,111	15,006	$ 16,723
AmeriGas Propane
Segment Reporting Information [Line Items]
Loss on extinguishment of debt			0
UGI International
Segment Reporting Information [Line Items]
Loss on extinguishment of debt			(11)
Midstream & Marketing
Segment Reporting Information [Line Items]
Loss on extinguishment of debt			0
Eliminations
Segment Reporting Information [Line Items]
Revenues from external customers	(99)	(40)	(396)	(236)
Cost of sales	(99)	(39)	(394)	(233)
Operating income	0	0	0	0
(Loss) income from equity investees	0	0	0	0
Loss on extinguishment of debt			0
Other non-operating income (expense), net	0	0	0	0
Earnings before interest expense and income taxes	0	0	0	0
Interest expense	0	0	0	0
(Loss) income before income taxes	0	0	0	0
Depreciation and amortization	0	0	0	0
Capital expenditures (including the effects of accruals)	0	0	0	0
Total assets	(182)	(267)	(182)	(267)
Eliminations | AmeriGas Propane
Segment Reporting Information [Line Items]
Revenues from external customers	0	0	0	0
Eliminations | UGI International
Segment Reporting Information [Line Items]
Revenues from external customers	0	0	0	0
Eliminations | Midstream & Marketing
Segment Reporting Information [Line Items]
Revenues from external customers	75	29	307	183
Eliminations | Utilities
Segment Reporting Information [Line Items]
Revenues from external customers	24	10	87	50
Operating Segments | AmeriGas Propane
Segment Reporting Information [Line Items]
Revenues from external customers	597	526	2,423	2,132
Cost of sales	370	267	1,333	970
Operating income	(10)	11	303	391
(Loss) income from equity investees	0	0	0	0
Loss on extinguishment of debt			0
Other non-operating income (expense), net	0	0	0	0
Earnings before interest expense and income taxes	(10)	11	303	391
Interest expense	(41)	(40)	(120)	(120)
(Loss) income before income taxes	(51)	(29)	183	271
Depreciation and amortization	44	43	132	130
Capital expenditures (including the effects of accruals)	28	26	99	83
Total assets	4,365	4,381	4,365	4,381
Operating Segments | UGI International
Segment Reporting Information [Line Items]
Revenues from external customers	738	572	3,011	2,106
Cost of sales	544	355	2,267	1,229
Operating income	22	40	211	322
(Loss) income from equity investees	0	0	0	0
Loss on extinguishment of debt			0
Other non-operating income (expense), net	4	1	17	4
Earnings before interest expense and income taxes	26	41	228	326
Interest expense	(7)	(8)	(22)	(21)
(Loss) income before income taxes	19	33	206	305
Depreciation and amortization	29	33	89	100
Capital expenditures (including the effects of accruals)	25	21	71	68
Total assets	4,410	3,749	4,410	3,749
Operating Segments | Midstream & Marketing
Segment Reporting Information [Line Items]
Revenues from external customers	525	261	1,731	1,086
Revenues, before intersegment effect	450	232	1,424	903
Cost of sales	436	196	1,389	776
Operating income	38	14	197	156
(Loss) income from equity investees	6	7	19	24
Loss on extinguishment of debt			0
Other non-operating income (expense), net	0	0	0	0
Earnings before interest expense and income taxes	44	21	216	180
Interest expense	(11)	(10)	(31)	(31)
(Loss) income before income taxes	33	11	185	149
Depreciation and amortization	20	19	57	56
Capital expenditures (including the effects of accruals)	9	3	25	32
Total assets	3,198	2,904	3,198	2,904
Operating Segments | Utilities
Segment Reporting Information [Line Items]
Revenues from external customers	274	181	1,400	923
Revenues, before intersegment effect	250	171	1,313	873
Cost of sales	121	67	701	401
Operating income	38	24	325	243
(Loss) income from equity investees	0	0	0	0
Loss on extinguishment of debt			0
Other non-operating income (expense), net	2	1	7	2
Earnings before interest expense and income taxes	40	25	332	245
Interest expense	(15)	(14)	(47)	(42)
(Loss) income before income taxes	25	11	285	203
Depreciation and amortization	37	29	108	87
Capital expenditures (including the effects of accruals)	139	112	351	255
Total assets	5,146	3,997	5,146	3,997
Corporate & Other
Segment Reporting Information [Line Items]
Revenues, before intersegment effect	(2)	(5)	1	(5)
Cost of sales	(11)	(330)	(345)	(520)
Operating income	11	302	327	452
(Loss) income from equity investees	(51)	(93)	(51)	(93)
Loss on extinguishment of debt			(11)
Other non-operating income (expense), net	14	(1)	17	(6)
Earnings before interest expense and income taxes	(26)	208	282	353
Interest expense	(8)	(5)	(25)	(19)
(Loss) income before income taxes	(34)	203	257	334
Depreciation and amortization	0	1	1	2
Capital expenditures (including the effects of accruals)	0	0	0	0
Total assets	$ 174	242	174	242
Intersegment revenues Corporate & Other
Segment Reporting Information [Line Items]
Revenues from external customers		$ 1	$ 2	$ 3