SCHEDULE I — CONDENSED FINANCIAL INFORMATION OF REGISTRANT (PARENT COMPANY) - STATEMENTS OF INCOME (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended								12 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Condensed Financial Statements, Captions [Line Items]
Revenues	$ 1,124	$ 1,199	$ 2,229	$ 2,007	$ 1,150	$ 1,364	$ 2,606	$ 2,200	$ 6,559	$ 7,320	$ 7,651
Costs and expenses:
Operating and administrative expenses									1,911	1,963	2,013
Other operating income, net									21	31	32
Total costs and expenses									5,577	6,703	6,586
Operating income	69	174	362	377	(99)	9	539	168	982	617	1,065
Pension and other postretirement plans non-service expense									0	1	0
Income tax expense (benefit)									135	93	33
Equity in income of unconsolidated subsidiaries									27	9	4
Net income attributable to UGI Corporation	$ 9	$ 85	$ 226	$ 212	$ (52)	$ (2)	$ 246	$ 64	532	256	719
Comprehensive income attributable to UGI Corporation									$ 602	$ 156	$ 702
Earnings per common share attributable to UGI Corporation stockholders:
Basic (in dollars per share)	$ 0.05	$ 0.41	$ 1.08	$ 1.01	$ (0.27)	$ (0.01)	$ 1.41	$ 0.37	$ 2.55	$ 1.44	$ 4.13
Diluted (in dollars per share)	$ 0.05	$ 0.41	$ 1.07	$ 1.00	$ (0.27)	$ (0.01)	$ 1.38	$ 0.36	$ 2.54	$ 1.41	$ 4.06
Weighted - average common shares outstanding (thousands):
Basic (in shares)	208,655	208,598	208,941	209,439	189,905	174,759	174,501	174,413	208,928	178,417	173,908
Diluted (in shares)	209,357	208,975	209,808	211,258	189,905	174,759	177,318	177,566	209,869	181,111	176,905
Parent Company
Condensed Financial Statements, Captions [Line Items]
Revenues									$ 0	$ 0	$ 0
Costs and expenses:
Operating and administrative expenses									56	50	63
Other operating income, net									(54)	(50)	(52)
Total costs and expenses									2	0	11
Operating income									(2)	0	(11)
Pension and other postretirement plans non-service expense									0	(1)	(1)
Interest expense									(32)	(6)
Loss before income taxes									(34)	(7)	(12)
Income tax expense (benefit)									17	(3)	6
Loss before equity in income of unconsolidated subsidiaries									(51)	(4)	(18)
Equity in income of unconsolidated subsidiaries									583	260	737
Net income attributable to UGI Corporation									532	256	719
Other comprehensive (loss) income									(12)	(3)	3
Equity in other comprehensive income (loss) of unconsolidated subsidiaries									82	(97)	(20)
Comprehensive income attributable to UGI Corporation									$ 602	$ 156	$ 702
Earnings per common share attributable to UGI Corporation stockholders:
Basic (in dollars per share)									$ 2.55	$ 1.44	$ 4.13
Diluted (in dollars per share)									$ 2.54	$ 1.41	$ 4.06
Weighted - average common shares outstanding (thousands):
Basic (in shares)									208,928	178,417	173,908
Diluted (in shares)									209,869	181,111	176,905