Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
AOCI Attributable to Parent, Net of Tax
Balance, beginning of period	$ 6,074
Other comprehensive income before reclassification adjustments	154	$ (22)
Amounts reclassified from AOCI	(5)	6
Other comprehensive (loss) income attributable to UGI	149	(16)
Balance, end of period	5,188	5,359
Total
AOCI Attributable to Parent, Net of Tax
Balance, beginning of period	(380)	(140)
Balance, end of period	(231)	(156)
Postretirement Benefit Plans
AOCI Attributable to Parent, Net of Tax
Balance, beginning of period	14	(17)
Other comprehensive income before reclassification adjustments	0	0
Amounts reclassified from AOCI	0	2
Other comprehensive (loss) income attributable to UGI	0	2
Balance, end of period	14	(15)
Derivative Instruments
AOCI Attributable to Parent, Net of Tax
Balance, beginning of period	37	(33)
Other comprehensive income before reclassification adjustments	3	10
Amounts reclassified from AOCI	(5)	4
Other comprehensive (loss) income attributable to UGI	(2)	14
Balance, end of period	35	(19)
Foreign Currency
AOCI Attributable to Parent, Net of Tax
Balance, beginning of period	(431)	(90)
Other comprehensive income before reclassification adjustments	151	(32)
Amounts reclassified from AOCI	0	0
Other comprehensive (loss) income attributable to UGI	151	(32)
Balance, end of period	$ (280)	$ (122)