Segment Information - Schedule of Segment Reporting Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2023	Mar. 31, 2022	Sep. 30, 2022
Segment Reporting Information [Line Items]
Revenues	$ 3,106	$ 3,466	$ 5,865	$ 6,139
Cost of sales	2,148	1,470	5,254	3,590
Operating income (loss)	255	1,332	(949)	1,264
(Loss) income from equity investees	0	5	1	13
Loss on extinguishments of debt	0	0	0	(11)
Other non-operating (loss) income, net	2	11	(26)	21
Earnings (loss) before interest expense and income taxes	257	1,348	(974)	1,287
Interest expense	(93)	(82)	(185)	(163)
Income (loss) before income taxes	164	1,266	(1,159)	1,124
Depreciation and amortization	132	128	263	257
Capital expenditures (including the effects of accruals)	214	170	392	345
Total assets	16,429	17,777	16,429	17,777	$ 17,575
Eliminations
Segment Reporting Information [Line Items]
Revenues	(128)	(179)	(277)	(297)
Cost of sales	(126)	(178)	(275)	(295)
Operating income (loss)	(1)	0	0	0
(Loss) income from equity investees	0	0	0	0
Loss on extinguishments of debt				0
Other non-operating (loss) income, net	0	0	0	0
Earnings (loss) before interest expense and income taxes	(1)	0	0	0
Interest expense	0	0	0	0
Income (loss) before income taxes	(1)	0	0	0
Depreciation and amortization	0	0	0	0
Capital expenditures (including the effects of accruals)	0	0	0	0
Total assets	(232)	(163)	(232)	(163)
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	98	138	213	232
Eliminations | Utilities
Segment Reporting Information [Line Items]
Revenues	28	40	61	63
Operating Segments | AmeriGas Propane
Segment Reporting Information [Line Items]
Revenues	867	1,048	1,633	1,826
Cost of sales	430	545	816	963
Operating income (loss)	138	227	248	313
(Loss) income from equity investees	0	0	0	0
Loss on extinguishments of debt				0
Other non-operating (loss) income, net	0	0	0	0
Earnings (loss) before interest expense and income taxes	138	227	248	313
Interest expense	(39)	(38)	(82)	(79)
Income (loss) before income taxes	99	189	166	234
Depreciation and amortization	45	44	89	88
Capital expenditures (including the effects of accruals)	28	36	51	71
Total assets	4,248	4,563	4,248	4,563
Operating Segments | UGI International
Segment Reporting Information [Line Items]
Revenues	948	1,224	1,825	2,273
Cost of sales	633	930	1,295	1,723
Operating income (loss)	120	111	176	189
(Loss) income from equity investees	(2)	0	(2)	0
Loss on extinguishments of debt				0
Other non-operating (loss) income, net	10	9	20	13
Earnings (loss) before interest expense and income taxes	128	120	194	202
Interest expense	(9)	(8)	(16)	(15)
Income (loss) before income taxes	119	112	178	187
Depreciation and amortization	28	29	56	60
Capital expenditures (including the effects of accruals)	30	23	57	46
Total assets	3,490	4,905	3,490	4,905
Operating Segments | Midstream & Marketing
Segment Reporting Information [Line Items]
Revenues	638	671	1,307	1,206
Revenues from external customers	540	533	1,094	974
Cost of sales	479	540	993	953
Operating income (loss)	103	85	209	159
(Loss) income from equity investees	2	5	3	13
Loss on extinguishments of debt				0
Other non-operating (loss) income, net	0	0	0	0
Earnings (loss) before interest expense and income taxes	105	90	212	172
Interest expense	(11)	(10)	(22)	(20)
Income (loss) before income taxes	94	80	190	152
Depreciation and amortization	22	18	43	37
Capital expenditures (including the effects of accruals)	23	10	34	16
Total assets	3,116	3,195	3,116	3,195
Operating Segments | Utilities
Segment Reporting Information [Line Items]
Revenues	774	707	1,366	1,126
Revenues from external customers	746	667	1,305	1,063
Cost of sales	426	380	755	580
Operating income (loss)	203	191	329	287
(Loss) income from equity investees	0	0	0	0
Loss on extinguishments of debt				0
Other non-operating (loss) income, net	2	3	4	5
Earnings (loss) before interest expense and income taxes	205	194	333	292
Interest expense	(21)	(16)	(42)	(32)
Income (loss) before income taxes	184	178	291	260
Depreciation and amortization	37	36	74	71
Capital expenditures (including the effects of accruals)	133	101	250	212
Total assets	5,643	5,106	5,643	5,106
Corporate & Other
Segment Reporting Information [Line Items]
Revenues from external customers	5	(6)	8	3
Cost of sales	306	(747)	1,670	(334)
Operating income (loss)	(308)	718	(1,911)	316
(Loss) income from equity investees	0	0	0	0
Loss on extinguishments of debt				(11)
Other non-operating (loss) income, net	(10)	(1)	(50)	3
Earnings (loss) before interest expense and income taxes	(318)	717	(1,961)	308
Interest expense	(13)	(10)	(23)	(17)
Income (loss) before income taxes	(331)	707	(1,984)	291
Depreciation and amortization	0	1	1	1
Capital expenditures (including the effects of accruals)	0	0	0	0
Total assets	164	171	164	171
Corporate & Other | AmeriGas Propane
Segment Reporting Information [Line Items]
Loss on extinguishments of debt				0
Corporate & Other | UGI International
Segment Reporting Information [Line Items]
Loss on extinguishments of debt				(11)
Corporate & Other | Midstream & Marketing
Segment Reporting Information [Line Items]
Loss on extinguishments of debt				0
Intersegment revenues Corporate & Other
Segment Reporting Information [Line Items]
Revenues	$ 2	$ 1	$ 3	$ 2