Segment Information - Schedule of Segment Reporting (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Segment Reporting Information [Line Items]
Revenues	$ 7,447	$ 6,559	$ 7,320
Cost of sales	2,614	3,149	4,323
Operating income (loss)	2,350	982	617
(Loss) income from equity investees	(63)	27	9
Loss on extinguishments of debt	0	0	(6)
Other non-operating income, net	12	(20)	39
Earnings (loss) before interest expense and income taxes	2,299	989	659
Interest expense	(310)	(322)	(258)
Income tax (expense) benefit	(522)	(135)	(93)
Noncontrolling interests’ net (income) loss	0	0	(52)
Net income attributable to UGI Corporation	1,467	532	256
Depreciation and amortization	502	484	448
Total assets	16,723	13,985	13,347
Short-term borrowings	367	347	796
Capital expenditures (including the effects of accruals)	674	665	707
Investments in equity investees	174	200	190
Eliminations
Segment Reporting Information [Line Items]
Revenues	(291)	(232)	(306)
Cost of sales	(288)	(229)	(301)
Operating income (loss)	0	0	0
(Loss) income from equity investees	0	0	0
Loss on extinguishments of debt			0
Other non-operating income, net	0	0	(1)
Earnings (loss) before interest expense and income taxes	0	0	(1)
Interest expense	0	0	0
Income tax (expense) benefit	0	0	0
Noncontrolling interests’ net (income) loss			0
Net income attributable to UGI Corporation	0	0	(1)
Depreciation and amortization	0	0	0
Total assets	(241)	(282)	(353)
Short-term borrowings	0	0	0
Capital expenditures (including the effects of accruals)	0	0	0
Investments in equity investees	0	0	0
Eliminations | AmeriGas Propane
Segment Reporting Information [Line Items]
Revenues	0	0	0
Eliminations | UGI International
Segment Reporting Information [Line Items]
Revenues	0	0	0
Eliminations | Midstream & Marketing
Segment Reporting Information [Line Items]
Revenues	224	182	235
Eliminations | UGI Utilities
Segment Reporting Information [Line Items]
Revenues	64	47	68
Operating Segments | AmeriGas Propane
Segment Reporting Information [Line Items]
Revenues	2,614	2,381	2,682
Cost of sales	1,217	960	1,191
Operating income (loss)	385	373	404
(Loss) income from equity investees	0	0	0
Loss on extinguishments of debt			0
Other non-operating income, net	0	0	0
Earnings (loss) before interest expense and income taxes	385	373	404
Interest expense	(159)	(164)	(167)
Income tax (expense) benefit	(58)	(53)	(26)
Noncontrolling interests’ net (income) loss			(143)
Net income attributable to UGI Corporation	168	156	68
Depreciation and amortization	173	178	179
Total assets	4,485	4,327	4,095
Short-term borrowings	170	186	328
Capital expenditures (including the effects of accruals)	130	135	107
Investments in equity investees	0	0	0
Operating Segments | UGI International
Segment Reporting Information [Line Items]
Revenues	2,651	2,127	2,372
Cost of sales	1,598	1,191	1,416
Operating income (loss)	314	241	229
(Loss) income from equity investees	0	0	0
Loss on extinguishments of debt			0
Other non-operating income, net	3	18	5
Earnings (loss) before interest expense and income taxes	317	259	234
Interest expense	(27)	(31)	(25)
Income tax (expense) benefit	(69)	(55)	(64)
Noncontrolling interests’ net (income) loss			0
Net income attributable to UGI Corporation	221	173	145
Depreciation and amortization	134	125	124
Total assets	4,421	3,123	2,975
Short-term borrowings	0	1	211
Capital expenditures (including the effects of accruals)	107	89	106
Investments in equity investees	11	10	12
Operating Segments | Midstream & Marketing
Segment Reporting Information [Line Items]
Revenues	1,406	1,247	1,516
Revenues from external customers	1,182	1,065	1,281
Cost of sales	1,033	892	1,241
Operating income (loss)	160	140	105
(Loss) income from equity investees	30	27	9
Loss on extinguishments of debt			0
Other non-operating income, net	0	1	0
Earnings (loss) before interest expense and income taxes	190	168	114
Interest expense	(42)	(42)	(9)
Income tax (expense) benefit	(41)	(34)	(27)
Noncontrolling interests’ net (income) loss			0
Net income attributable to UGI Corporation	107	92	78
Depreciation and amortization	76	75	51
Total assets	3,010	2,775	2,745
Short-term borrowings	0	19	91
Capital expenditures (including the effects of accruals)	43	93	138
Investments in equity investees	163	190	178
Operating Segments | UGI Utilities
Segment Reporting Information [Line Items]
Revenues	1,079	1,030	1,049
Revenues from external customers	1,015	983	981
Cost of sales	458	448	481
Operating income (loss)	241	229	224
(Loss) income from equity investees	0	0	0
Loss on extinguishments of debt			0
Other non-operating income, net	1	0	2
Earnings (loss) before interest expense and income taxes	242	229	226
Interest expense	(56)	(54)	(50)
Income tax (expense) benefit	(42)	(39)	(43)
Noncontrolling interests’ net (income) loss			0
Net income attributable to UGI Corporation	144	136	133
Depreciation and amortization	119	105	93
Total assets	4,859	3,809	3,560
Short-term borrowings	197	141	166
Capital expenditures (including the effects of accruals)	394	348	355
Investments in equity investees	0	0	0
Corporate & Other
Segment Reporting Information [Line Items]
Revenues	(12)	6	7
Revenues from external customers	(15)	3	4
Cost of sales	(1,404)	(113)	295
Operating income (loss)	1,250	(1)	(345)
(Loss) income from equity investees	(93)	0	0
Loss on extinguishments of debt			(6)
Other non-operating income, net	8	(39)	33
Earnings (loss) before interest expense and income taxes	1,165	(40)	(318)
Interest expense	(26)	(31)	(7)
Income tax (expense) benefit	(312)	46	67
Noncontrolling interests’ net (income) loss			91
Net income attributable to UGI Corporation	827	(25)	(167)
Depreciation and amortization	0	1	1
Total assets	189	233	325
Short-term borrowings	0	0	0
Capital expenditures (including the effects of accruals)	0	0	1
Investments in equity investees	0	0	0
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			(6)
Corporate & Other | Midstream & Marketing
Segment Reporting Information [Line Items]
Loss on extinguishments of debt			0
Corporate, Intersegment Eliminations & Other
Segment Reporting Information [Line Items]
Revenues	$ 3	$ 3	$ 3