Segment Information - Schedule of Segment Reporting (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Segment Reporting Information [Line Items]
Revenues from external customers	$ 7,287	$ 7,210	$ 8,928
Revenues	7,287	7,210	8,928
Cost of sales	3,654	3,529	6,937
Operating and administrative expenses	2,011	2,132	2,158
Depreciation and amortization	561	551	532
Equity in income (loss) of unconsolidated subsidiaries	5	(19)	2
Other segment income (loss)	41	(245)	(761)
Earnings (loss) before interest expense and income taxes	1,107	734	(1,458)
Interest expense	(411)	(394)	(379)
Income tax benefit (expense)	(18)	(71)	335
Net income (loss) attributable to UGI Corporation	678	269	(1,502)
Total assets	15,462	15,098	15,401
Capital expenditures (including the effects of accruals)	844	805	956
UGI Utilities, Inc.
Segment Reporting Information [Line Items]
Segment expense	388	363	368
Eliminations
Segment Reporting Information [Line Items]
Revenues from external customers	0	0	0
Revenues	(350)	(266)	(326)
Cost of sales	(350)	(266)	(325)
Operating and administrative expenses	(107)	(84)	(85)
Depreciation and amortization	0	0	0
Equity in income (loss) of unconsolidated subsidiaries	0	0	0
Other segment income (loss)	(119)	(84)	(84)
Earnings (loss) before interest expense and income taxes	(12)	0	0
Interest expense	12	0	0
Income tax benefit (expense)	0	0	0
Net income (loss) attributable to UGI Corporation	0	0	0
Total assets	(376)	(733)	(173)
Capital expenditures (including the effects of accruals)	0	0
Eliminations | UGI Utilities, Inc.
Segment Reporting Information [Line Items]
Revenues	80	49	74
Eliminations | Midstream & Marketing
Segment Reporting Information [Line Items]
Revenues	270	217	251
Eliminations | UGI International
Segment Reporting Information [Line Items]
Revenues	0	0	0
Eliminations | AmeriGas Propane
Segment Reporting Information [Line Items]
Revenues	0	0	0
Operating Segments | UGI Utilities, Inc.
Segment Reporting Information [Line Items]
Revenues from external customers	1,681	1,549	1,780
Revenues	1,761	1,598	1,854
Cost of sales	774	650	953
Operating and administrative expenses	412	387	392
Depreciation and amortization	178	166	152
Equity in income (loss) of unconsolidated subsidiaries	0	0	0
Other segment income (loss)	6	5	8
Earnings (loss) before interest expense and income taxes	403	400	365
Interest expense	(100)	(93)	(82)
Income tax benefit (expense)	(66)	(70)	(64)
Net income (loss) attributable to UGI Corporation	237	237	219
Total assets	6,434	5,963	5,691
Capital expenditures (including the effects of accruals)	556	482	563
Operating Segments | Midstream & Marketing
Segment Reporting Information [Line Items]
Revenues from external customers	1,213	1,152	1,596
Revenues	1,483	1,369	1,847
Cost of sales	989	864	1,360
Operating and administrative expenses	129	125	133
Depreciation and amortization	81	86	86
Equity in income (loss) of unconsolidated subsidiaries	6	12	6
Other segment income (loss)	3	7	17
Earnings (loss) before interest expense and income taxes	293	313	291
Interest expense	(49)	(41)	(45)
Income tax benefit (expense)	25	(34)	(53)
Net income (loss) attributable to UGI Corporation	269	238	193
Total assets	3,187	3,183	3,160
Capital expenditures (including the effects of accruals)	114	150	130
Operating Segments | UGI International
Segment Reporting Information [Line Items]
Revenues	2,119	2,279	2,965
Cost of sales	1,179	1,301	2,045
Operating and administrative expenses	543	578	623
Depreciation and amortization	123	119	116
Equity in income (loss) of unconsolidated subsidiaries	(1)	(5)	(4)
Other segment income (loss)	41	47	57
Earnings (loss) before interest expense and income taxes	314	323	234
Interest expense	(46)	(44)	(37)
Income tax benefit (expense)	(26)	(17)	(25)
Net income (loss) attributable to UGI Corporation	242	262	172
Total assets	3,134	2,906	3,105
Capital expenditures (including the effects of accruals)	93	87	129
Operating Segments | AmeriGas Propane
Segment Reporting Information [Line Items]
Revenues	2,276	2,271	2,581
Cost of sales	1,054	1,059	1,250
Operating and administrative expenses	924	933	950
Depreciation and amortization	178	178	177
Equity in income (loss) of unconsolidated subsidiaries	0	0	0
Other segment income (loss)	46	41	64
Earnings (loss) before interest expense and income taxes	166	142	268
Interest expense	(144)	(156)	(163)
Income tax benefit (expense)	14	(9)	(34)
Net income (loss) attributable to UGI Corporation	36	(23)	71
Total assets	2,914	3,051	3,415
Capital expenditures (including the effects of accruals)	81	86	134
Corporate & Other
Segment Reporting Information [Line Items]
Revenues from external customers	(2)	(41)	6
Cost of sales	8	(79)	1,654
Operating and administrative expenses	110	193	145
Depreciation and amortization	1	2	1
Equity in income (loss) of unconsolidated subsidiaries	0	(26)	0
Other segment income (loss)	64	(261)	(823)
Earnings (loss) before interest expense and income taxes	(57)	(444)	(2,616)
Interest expense	(84)	(60)	(52)
Income tax benefit (expense)	35	59	511
Net income (loss) attributable to UGI Corporation	(106)	(445)	(2,157)
Total assets	169	728	203
Capital expenditures (including the effects of accruals)	0	0	0
Corporate, Intersegment Eliminations & Other
Segment Reporting Information [Line Items]
Revenues	$ 0	$ 0	$ 1