Segment Information - Schedule of Segment Reporting (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Segment Reporting Information [Line Items]
Revenues	$ 7,210	$ 8,928	$ 10,106
Cost of sales	3,529	6,937	5,973
Operating income (loss)	770	(1,444)	1,666
(Loss) income from equity investees	(19)	2	(14)
Loss on extinguishments of debt	(9)	(9)	(11)
Other non-operating (loss) income, net	(8)	(7)	75
Earnings (loss) before interest expense and income taxes	734	(1,458)	1,716
Interest expense	(394)	(379)	(329)
Income tax benefit (expense)	(71)	335	(313)
Noncontrolling interests’ net income	0	0	(1)
Net income (loss) attributable to UGI Corporation	269	(1,502)	1,073
Depreciation and amortization	551	532	518
Total assets	15,098	15,401	17,575
Short-term borrowings	465	649	368
Capital expenditures (including the effects of accruals)	805	956	835
Investments in equity investees	370	299	130
Midstream & Marketing
Segment Reporting Information [Line Items]
Loss on extinguishments of debt	(1)	0	0
Investments in equity investees	359	264
UGI International
Segment Reporting Information [Line Items]
Loss on extinguishments of debt	0	0	(11)
Investments in equity investees	10	35
AmeriGas Propane
Segment Reporting Information [Line Items]
Loss on extinguishments of debt	(8)	(9)	0
Elim- inations
Segment Reporting Information [Line Items]
Revenues	(266)	(326)	(477)
Cost of sales	(266)	(325)	(474)
Operating income (loss)	0	0	0
(Loss) income from equity investees	0	0	0
Loss on extinguishments of debt	0	0	0
Other non-operating (loss) income, net	0	0	0
Earnings (loss) before interest expense and income taxes	0	0	0
Interest expense	0	0	0
Income tax benefit (expense)	0	0	0
Noncontrolling interests’ net income			0
Net income (loss) attributable to UGI Corporation	0	0	0
Depreciation and amortization	0	0	0
Total assets	(733)	(173)	(203)
Short-term borrowings	0	0	0
Capital expenditures (including the effects of accruals)	0		0
Investments in equity investees	0	0	0
Elim- inations | UGI Utilities, Inc.
Segment Reporting Information [Line Items]
Revenues	49	74	105
Elim- inations | Midstream & Marketing
Segment Reporting Information [Line Items]
Revenues	217	251	369
Elim- inations | UGI International
Segment Reporting Information [Line Items]
Revenues	0	0	0
Elim- inations | AmeriGas Propane
Segment Reporting Information [Line Items]
Revenues	0	0	0
Operating Segments | UGI Utilities, Inc.
Segment Reporting Information [Line Items]
Revenues	1,598	1,854	1,620
Revenues from external customers	1,549	1,780	1,515
Cost of sales	650	953	798
Operating income (loss)	394	357	327
(Loss) income from equity investees	0	0	0
Loss on extinguishments of debt	0	0	0
Other non-operating (loss) income, net	6	8	9
Earnings (loss) before interest expense and income taxes	400	365	336
Interest expense	(93)	(82)	(65)
Income tax benefit (expense)	(70)	(64)	(65)
Noncontrolling interests’ net income			0
Net income (loss) attributable to UGI Corporation	237	219	206
Depreciation and amortization	166	152	144
Total assets	5,963	5,691	5,354
Short-term borrowings	286	332	236
Capital expenditures (including the effects of accruals)	482	563	562
Investments in equity investees	0	0	0
Operating Segments | Midstream & Marketing
Segment Reporting Information [Line Items]
Revenues	1,369	1,847	2,326
Revenues from external customers	1,152	1,596	1,957
Cost of sales	864	1,360	1,876
Operating income (loss)	301	285	246
(Loss) income from equity investees	12	6	23
Loss on extinguishments of debt	0	0	0
Other non-operating (loss) income, net	0	0	0
Earnings (loss) before interest expense and income taxes	313	291	269
Interest expense	(41)	(45)	(41)
Income tax benefit (expense)	(34)	(53)	(65)
Noncontrolling interests’ net income			0
Net income (loss) attributable to UGI Corporation	238	193	163
Depreciation and amortization	86	86	79
Total assets	3,183	3,160	3,286
Short-term borrowings	0	103	0
Capital expenditures (including the effects of accruals)	150	130	38
Investments in equity investees	359	264	109
Operating Segments | UGI International
Segment Reporting Information [Line Items]
Revenues	2,279	2,965	3,686
Cost of sales	1,301	2,045	2,751
Operating income (loss)	311	215	237
(Loss) income from equity investees	(5)	(4)	(2)
Loss on extinguishments of debt	0	0	0
Other non-operating (loss) income, net	17	23	19
Earnings (loss) before interest expense and income taxes	323	234	254
Interest expense	(44)	(37)	(28)
Income tax benefit (expense)	(17)	(25)	(50)
Noncontrolling interests’ net income			(1)
Net income (loss) attributable to UGI Corporation	262	172	175
Depreciation and amortization	119	116	116
Total assets	2,906	3,105	4,610
Short-term borrowings	128	214	1
Capital expenditures (including the effects of accruals)	87	129	107
Investments in equity investees	10	35	20
Operating Segments | AmeriGas Propane
Segment Reporting Information [Line Items]
Revenues	2,271	2,581	2,943
Cost of sales	1,059	1,250	1,613
Operating income (loss)	142	268	307
(Loss) income from equity investees	0	0	0
Loss on extinguishments of debt	0	0	0
Other non-operating (loss) income, net	0	0	0
Earnings (loss) before interest expense and income taxes	142	268	307
Interest expense	(156)	(163)	(160)
Income tax benefit (expense)	(9)	(34)	(35)
Noncontrolling interests’ net income			0
Net income (loss) attributable to UGI Corporation	(23)	71	112
Depreciation and amortization	178	177	177
Total assets	3,051	3,415	4,332
Short-term borrowings	51	0	131
Capital expenditures (including the effects of accruals)	86	134	128
Investments in equity investees	0	0	0
Corporate & Other
Segment Reporting Information [Line Items]
Revenues from external customers	(41)	6	5
Cost of sales	(79)	1,654	(591)
Operating income (loss)	(378)	(2,569)	549
(Loss) income from equity investees	(26)	0	(35)
Loss on extinguishments of debt	(9)	(9)	(11)
Other non-operating (loss) income, net	(31)	(38)	47
Earnings (loss) before interest expense and income taxes	(444)	(2,616)	550
Interest expense	(60)	(52)	(35)
Income tax benefit (expense)	59	511	(98)
Noncontrolling interests’ net income			0
Net income (loss) attributable to UGI Corporation	(445)	(2,157)	417
Depreciation and amortization	2	1	2
Total assets	728	203	196
Short-term borrowings	0	0	0
Capital expenditures (including the effects of accruals)	0	0	0
Investments in equity investees	1	0	1
Corporate, Intersegment Eliminations & Other
Segment Reporting Information [Line Items]
Revenues	$ 0	$ 1	$ 3