Segment Information - Schedule of Segment Reporting Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Sep. 30, 2022
Segment Reporting Information [Line Items]
Revenues	$ 1,659	$ 2,033	$ 7,524	$ 8,172
Cost of sales	1,104	1,361	6,358	4,951
Operating (loss) income	(732)	99	(1,681)	1,363
(Loss) income from equity investees	1	(45)	2	(32)
Loss on extinguishments of debt	(9)	0	(9)	(11)
Other non-operating (loss) income, net	1	20	(25)	41
(Loss) earnings before interest expense and income taxes	(739)	74	(1,713)	1,361
Interest expense	(96)	(82)	(281)	(245)
(Loss) income before income taxes	(835)	(8)	(1,994)	1,116
Depreciation and amortization	134	130	397	387
Capital expenditures (including the effects of accruals)	255	201	647	546
Total assets	15,243	17,111	15,243	17,111	$ 17,575
Eliminations
Segment Reporting Information [Line Items]
Revenues	(25)	(99)	(302)	(396)
Cost of sales	(26)	(99)	(301)	(394)
Operating (loss) income	0	0	0	0
(Loss) income from equity investees	0	0	0	0
Loss on extinguishments of debt	0		0	0
Other non-operating (loss) income, net	0	0	0	0
(Loss) 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)	(182)	(182)	(182)
Eliminations | AmeriGas Propane
Segment Reporting Information [Line Items]
Revenues	0	0	0	0
Eliminations | UGI International
Segment Reporting Information [Line Items]
Revenues	0	0	0	0
Eliminations | Midstream & Marketing
Segment Reporting Information [Line Items]
Revenues	19	75	232	307
Eliminations | Utilities
Segment Reporting Information [Line Items]
Revenues	8	24	69	87
Operating Segments | AmeriGas Propane
Segment Reporting Information [Line Items]
Revenues	514	597	2,147	2,423
Cost of sales	251	370	1,067	1,333
Operating (loss) income	(8)	(10)	240	303
(Loss) income from equity investees	0	0	0	0
Loss on extinguishments of debt	0		0	0
Other non-operating (loss) income, net	0	0	0	0
(Loss) earnings before interest expense and income taxes	(8)	(10)	240	303
Interest expense	(40)	(41)	(122)	(120)
(Loss) income before income taxes	(48)	(51)	118	183
Depreciation and amortization	43	44	132	132
Capital expenditures (including the effects of accruals)	42	28	93	99
Total assets	3,443	4,365	3,443	4,365
Operating Segments | UGI International
Segment Reporting Information [Line Items]
Revenues	611	738	2,436	3,011
Cost of sales	418	544	1,713	2,267
Operating (loss) income	21	22	197	211
(Loss) income from equity investees	0	0	(2)	0
Loss on extinguishments of debt	0		0	0
Other non-operating (loss) income, net	1	4	21	17
(Loss) earnings before interest expense and income taxes	22	26	216	228
Interest expense	(10)	(7)	(26)	(22)
(Loss) income before income taxes	12	19	190	206
Depreciation and amortization	30	29	86	89
Capital expenditures (including the effects of accruals)	27	25	84	71
Total assets	3,179	4,410	3,179	4,410
Operating Segments | Midstream & Marketing
Segment Reporting Information [Line Items]
Revenues	279	525	1,586	1,731
Revenues from external customers	260	450	1,354	1,424
Cost of sales	192	436	1,185	1,389
Operating (loss) income	40	38	249	197
(Loss) income from equity investees	1	6	4	19
Loss on extinguishments of debt	0		0	0
Other non-operating (loss) income, net	0	0	0	0
(Loss) earnings before interest expense and income taxes	41	44	253	216
Interest expense	(11)	(11)	(33)	(31)
(Loss) income before income taxes	30	33	220	185
Depreciation and amortization	22	20	65	57
Capital expenditures (including the effects of accruals)	40	9	74	25
Total assets	3,050	3,198	3,050	3,198
Operating Segments | Utilities
Segment Reporting Information [Line Items]
Revenues	278	274	1,644	1,400
Revenues from external customers	270	250	1,575	1,313
Cost of sales	118	121	873	701
Operating (loss) income	32	38	361	325
(Loss) income from equity investees	0	0	0	0
Loss on extinguishments of debt	0		0	0
Other non-operating (loss) income, net	2	2	6	7
(Loss) earnings before interest expense and income taxes	34	40	367	332
Interest expense	(20)	(15)	(62)	(47)
(Loss) income before income taxes	14	25	305	285
Depreciation and amortization	38	37	112	108
Capital expenditures (including the effects of accruals)	146	139	396	351
Total assets	5,560	5,146	5,560	5,146
Corporate & Other
Segment Reporting Information [Line Items]
Revenues from external customers	4	(2)	12	1
Cost of sales	151	(11)	1,821	(345)
Operating (loss) income	(817)	11	(2,728)	327
(Loss) income from equity investees	0	(51)	0	(51)
Loss on extinguishments of debt	(9)		(9)	(11)
Other non-operating (loss) income, net	(2)	14	(52)	17
(Loss) earnings before interest expense and income taxes	(828)	(26)	(2,789)	282
Interest expense	(15)	(8)	(38)	(25)
(Loss) income before income taxes	(843)	(34)	(2,827)	257
Depreciation and amortization	1	0	2	1
Capital expenditures (including the effects of accruals)	0	0	0	0
Total assets	193	174	193	174
Corporate & Other | AmeriGas Propane
Segment Reporting Information [Line Items]
Loss on extinguishments of debt	(9)		(9)	0
Corporate & Other | UGI International
Segment Reporting Information [Line Items]
Loss on extinguishments of debt	0		0	(11)
Corporate & Other | Midstream & Marketing
Segment Reporting Information [Line Items]
Loss on extinguishments of debt	0		0	0
Intersegment revenues Corporate & Other
Segment Reporting Information [Line Items]
Revenues	$ (2)	$ 0	$ 1	$ 2