Segment Information - Schedule of Segment Reporting Information (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Sep. 30, 2022
Segment Reporting Information [Line Items]
Revenues	$ 2,759	$ 2,673
Cost of sales	3,106	2,120
Operating (loss) income	(1,204)	(68)
Income from equity investees	1	8
Loss on extinguishments of debt	0	(11)
Other non-operating (loss) income, net	(28)	10
(Loss) earnings before interest expense and income taxes	(1,231)	(61)
Interest expense	(92)	(81)
Loss before income taxes	(1,323)	(142)
Depreciation and amortization	131	129
Capital expenditures (including the effects of accruals)	178	175
Total assets	17,128	16,800	$ 17,575
AmeriGas Propane
Segment Reporting Information [Line Items]
Loss on extinguishments of debt		0
UGI International
Segment Reporting Information [Line Items]
Loss on extinguishments of debt		(11)
Midstream & Marketing
Segment Reporting Information [Line Items]
Loss on extinguishments of debt		0
Eliminations
Segment Reporting Information [Line Items]
Revenues	(149)	(118)
Cost of sales	(149)	(117)
Operating (loss) income	1	0
Income from equity investees	0	0
Loss on extinguishments of debt		0
Other non-operating (loss) income, net	0	0
(Loss) earnings before interest expense and income taxes	1	0
Interest expense	0	0
Loss before income taxes	1	0
Depreciation and amortization	0	0
Capital expenditures (including the effects of accruals)	0	0
Total assets	(252)	(269)
Eliminations | AmeriGas Propane
Segment Reporting Information [Line Items]
Revenues	0	0
Eliminations | UGI International
Segment Reporting Information [Line Items]
Revenues	0	0
Eliminations | Midstream & Marketing
Segment Reporting Information [Line Items]
Revenues	115	94
Eliminations | Utilities
Segment Reporting Information [Line Items]
Revenues	33	23
Operating Segments | AmeriGas Propane
Segment Reporting Information [Line Items]
Revenues	766	778
Cost of sales	386	418
Operating (loss) income	110	86
Income from equity investees	0	0
Loss on extinguishments of debt		0
Other non-operating (loss) income, net	0	0
(Loss) earnings before interest expense and income taxes	110	86
Interest expense	(43)	(41)
Loss before income taxes	67	45
Depreciation and amortization	44	44
Capital expenditures (including the effects of accruals)	23	35
Total assets	4,331	4,614
Operating Segments | UGI International
Segment Reporting Information [Line Items]
Revenues	877	1,049
Cost of sales	662	793
Operating (loss) income	56	78
Income from equity investees	0	0
Loss on extinguishments of debt		0
Other non-operating (loss) income, net	10	4
(Loss) earnings before interest expense and income taxes	66	82
Interest expense	(7)	(7)
Loss before income taxes	59	75
Depreciation and amortization	28	31
Capital expenditures (including the effects of accruals)	27	23
Total assets	3,889	4,197
Operating Segments | Midstream & Marketing
Segment Reporting Information [Line Items]
Revenues	669	535
Revenues from external customers	554	441
Cost of sales	514	413
Operating (loss) income	106	74
Income from equity investees	1	8
Loss on extinguishments of debt		0
Other non-operating (loss) income, net	0	0
(Loss) earnings before interest expense and income taxes	107	82
Interest expense	(11)	(10)
Loss before income taxes	96	72
Depreciation and amortization	21	19
Capital expenditures (including the effects of accruals)	11	6
Total assets	3,298	2,999
Operating Segments | Utilities
Segment Reporting Information [Line Items]
Revenues	592	419
Revenues from external customers	559	396
Cost of sales	329	200
Operating (loss) income	126	96
Income from equity investees	0	0
Loss on extinguishments of debt		0
Other non-operating (loss) income, net	2	2
(Loss) earnings before interest expense and income taxes	128	98
Interest expense	(21)	(16)
Loss before income taxes	107	82
Depreciation and amortization	37	35
Capital expenditures (including the effects of accruals)	117	111
Total assets	5,680	5,071
Corporate & Other
Segment Reporting Information [Line Items]
Revenues from external customers	3	9
Cost of sales	1,364	413
Operating (loss) income	(1,603)	(402)
Income from equity investees	0	0
Loss on extinguishments of debt		(11)
Other non-operating (loss) income, net	(40)	4
(Loss) earnings before interest expense and income taxes	(1,643)	(409)
Interest expense	(10)	(7)
Loss before income taxes	(1,653)	(416)
Depreciation and amortization	1	0
Capital expenditures (including the effects of accruals)	0	0
Total assets	182	188
Intersegment revenues Corporate & Other
Segment Reporting Information [Line Items]
Revenues	$ 1	$ 1