Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
AOCI Attributable to Parent, Net of Tax
Balance, beginning of period			$ 6,074
Other comprehensive income (loss) before reclassification adjustments	$ 30	$ (98)	179	$ (149)
Amounts reclassified from AOCI	(11)	3	(21)	16
Other comprehensive (loss) income attributable to UGI	19	(95)	158	(133)
Balance, end of period	4,373	6,005	4,373	6,005
Total
AOCI Attributable to Parent, Net of Tax
Balance, beginning of period	(241)	(178)	(380)	(140)
Balance, end of period	(222)	(273)	(222)	(273)
Postretirement Benefit Plans
AOCI Attributable to Parent, Net of Tax
Balance, beginning of period	14	(14)	14	(17)
Other comprehensive income (loss) before reclassification adjustments	0	0	0	0
Amounts reclassified from AOCI	(1)	0	(1)	3
Other comprehensive (loss) income attributable to UGI	(1)	0	(1)	3
Balance, end of period	13	(14)	13	(14)
Derivative Instruments
AOCI Attributable to Parent, Net of Tax
Balance, beginning of period	15	11	37	(33)
Other comprehensive income (loss) before reclassification adjustments	22	8	10	42
Amounts reclassified from AOCI	(10)	3	(20)	13
Other comprehensive (loss) income attributable to UGI	12	11	(10)	55
Balance, end of period	27	22	27	22
Foreign Currency
AOCI Attributable to Parent, Net of Tax
Balance, beginning of period	(270)	(175)	(431)	(90)
Other comprehensive income (loss) before reclassification adjustments	8	(106)	169	(191)
Amounts reclassified from AOCI	0	0	0	0
Other comprehensive (loss) income attributable to UGI	8	(106)	169	(191)
Balance, end of period	$ (262)	$ (281)	$ (262)	$ (281)