Segment Information - Schedule of Segment Reporting (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Segment Reporting Information [Line Items]
Revenues	$ 8,928	$ 10,106	$ 7,447
Cost of sales	6,937	5,973	2,614
Operating income	(1,444)	1,666	2,350
Income (loss) from equity investees	2	(14)	(63)
Loss on extinguishment of debt	(9)	(11)	0
Other non-operating (loss) income, net	(7)	75	12
Earnings before interest expense and income taxes	(1,458)	1,716	2,299
Interest expense	(379)	(329)	(310)
Income tax expense	335	(313)	(522)
Noncontrolling interests’ net (income) loss	0	(1)	0
Net (loss) income attributable to UGI Corporation	(1,502)	1,073	1,467
Depreciation and amortization	532	518	502
Total assets	15,401	17,575	16,723
Short-term borrowings	649	368	367
Capital expenditures (including the effects of accruals)	956	835	674
Investments in equity investees	299	130	174
UGI International
Segment Reporting Information [Line Items]
Investments in equity investees	35	21
Midstream & Marketing
Segment Reporting Information [Line Items]
Investments in equity investees	264	109
Elim- inations
Segment Reporting Information [Line Items]
Revenues	(326)	(477)	(291)
Cost of sales	(325)	(474)	(288)
Operating income	0	0	0
Income (loss) from equity investees	0	0	0
Loss on extinguishment of debt	0	0
Other non-operating (loss) income, net	0	0	0
Earnings before interest expense and income taxes	0	0	0
Interest expense	0	0	0
Income tax expense	0	0	0
Noncontrolling interests’ net (income) loss		0
Net (loss) income attributable to UGI Corporation	0	0	0
Depreciation and amortization	0	0	0
Total assets	(173)	(203)	(241)
Short-term borrowings	0	0	0
Capital expenditures (including the effects of accruals)		0	0
Investments in equity investees	0	0	0
Elim- inations | AmeriGas Propane
Segment Reporting Information [Line Items]
Revenues	0	0	0
Elim- inations | UGI International
Segment Reporting Information [Line Items]
Revenues	0	0	0
Elim- inations | Midstream & Marketing
Segment Reporting Information [Line Items]
Revenues	251	369	224
Elim- inations | Utilities
Segment Reporting Information [Line Items]
Revenues	74	105	64
Operating Segments | AmeriGas Propane
Segment Reporting Information [Line Items]
Revenues	2,581	2,943	2,614
Cost of sales	1,250	1,613	1,217
Operating income	268	307	385
Income (loss) from equity investees	0	0	0
Loss on extinguishment of debt	0	0
Other non-operating (loss) income, net	0	0	0
Earnings before interest expense and income taxes	268	307	385
Interest expense	(163)	(160)	(159)
Income tax expense	(34)	(35)	(58)
Noncontrolling interests’ net (income) loss		0
Net (loss) income attributable to UGI Corporation	71	112	168
Depreciation and amortization	177	177	173
Total assets	3,415	4,332	4,485
Short-term borrowings	0	131	170
Capital expenditures (including the effects of accruals)	134	128	130
Investments in equity investees	0	0	0
Operating Segments | UGI International
Segment Reporting Information [Line Items]
Revenues	2,965	3,686	2,651
Cost of sales	2,045	2,751	1,598
Operating income	215	237	314
Income (loss) from equity investees	(4)	(2)	0
Loss on extinguishment of debt	0	0
Other non-operating (loss) income, net	23	19	3
Earnings before interest expense and income taxes	234	254	317
Interest expense	(37)	(28)	(27)
Income tax expense	(25)	(50)	(69)
Noncontrolling interests’ net (income) loss		(1)
Net (loss) income attributable to UGI Corporation	172	175	221
Depreciation and amortization	116	116	134
Total assets	3,105	4,610	4,421
Short-term borrowings	214	1	0
Capital expenditures (including the effects of accruals)	129	107	107
Investments in equity investees	35	20	11
Operating Segments | Midstream & Marketing
Segment Reporting Information [Line Items]
Revenues	1,847	2,326	1,406
Revenues from external customers	1,596	1,957	1,182
Cost of sales	1,360	1,876	1,033
Operating income	285	246	160
Income (loss) from equity investees	6	23	30
Loss on extinguishment of debt	0	0
Other non-operating (loss) income, net	0	0	0
Earnings before interest expense and income taxes	291	269	190
Interest expense	(45)	(41)	(42)
Income tax expense	(53)	(65)	(41)
Noncontrolling interests’ net (income) loss		0
Net (loss) income attributable to UGI Corporation	193	163	107
Depreciation and amortization	86	79	76
Total assets	3,160	3,286	3,010
Short-term borrowings	103	0	0
Capital expenditures (including the effects of accruals)	130	38	43
Investments in equity investees	264	109	163
Operating Segments | Utilities
Segment Reporting Information [Line Items]
Revenues	1,854	1,620	1,079
Revenues from external customers	1,780	1,515	1,015
Cost of sales	953	798	458
Operating income	357	327	241
Income (loss) from equity investees	0	0	0
Loss on extinguishment of debt	0	0
Other non-operating (loss) income, net	8	9	1
Earnings before interest expense and income taxes	365	336	242
Interest expense	(82)	(65)	(56)
Income tax expense	(64)	(65)	(42)
Noncontrolling interests’ net (income) loss		0
Net (loss) income attributable to UGI Corporation	219	206	144
Depreciation and amortization	152	144	119
Total assets	5,691	5,354	4,859
Short-term borrowings	332	236	197
Capital expenditures (including the effects of accruals)	563	562	394
Investments in equity investees	0	0	0
Corporate & Other
Segment Reporting Information [Line Items]
Revenues	7	8	(12)
Revenues from external customers	6	5	(15)
Cost of sales	1,654	(591)	(1,404)
Operating income	(2,569)	549	1,250
Income (loss) from equity investees	0	(35)	(93)
Loss on extinguishment of debt	(9)	(11)
Other non-operating (loss) income, net	(38)	47	8
Earnings before interest expense and income taxes	(2,616)	550	1,165
Interest expense	(52)	(35)	(26)
Income tax expense	511	(98)	(312)
Noncontrolling interests’ net (income) loss		0
Net (loss) income attributable to UGI Corporation	(2,157)	417	827
Depreciation and amortization	1	2	0
Total assets	203	196	189
Short-term borrowings	0	0	0
Capital expenditures (including the effects of accruals)	0	0	0
Investments in equity investees	0	1	0
Corporate & Other | AmeriGas Propane
Segment Reporting Information [Line Items]
Loss on extinguishment of debt	(9)	0
Corporate & Other | UGI International
Segment Reporting Information [Line Items]
Loss on extinguishment of debt	0	(11)
Corporate & Other | Midstream & Marketing
Segment Reporting Information [Line Items]
Loss on extinguishment of debt	0	0
Corporate, Intersegment Eliminations & Other
Segment Reporting Information [Line Items]
Revenues	$ 1	$ 3	$ 3