Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
AOCI Attributable to Parent, Net of Tax
Balance, beginning of period			$ 5,531
Other comprehensive income (loss) before reclassification adjustments	$ (98)	$ 16	(149)	$ 27
Amounts reclassified from AOCI	3	5	16	15
Other comprehensive income (loss) attributable to UGI	(95)	21	(133)	42
Balance, end of period	6,005	5,106	6,005	5,106
Postretirement Benefit Plans
AOCI Attributable to Parent, Net of Tax
Balance, beginning of period	(14)	(25)	(17)	(26)
Other comprehensive income (loss) before reclassification adjustments	0	0	0	0
Amounts reclassified from AOCI	0	0	3	1
Other comprehensive income (loss) attributable to UGI	0	0	3	1
Balance, end of period	(14)	(25)	(14)	(25)
Derivative Instruments
AOCI Attributable to Parent, Net of Tax
Balance, beginning of period	11	(41)	(33)	(54)
Other comprehensive income (loss) before reclassification adjustments	8	0	42	4
Amounts reclassified from AOCI	3	5	13	14
Other comprehensive income (loss) attributable to UGI	11	5	55	18
Balance, end of period	22	(36)	22	(36)
Foreign Currency
AOCI Attributable to Parent, Net of Tax
Balance, beginning of period	(175)	(60)	(90)	(67)
Other comprehensive income (loss) before reclassification adjustments	(106)	16	(191)	23
Amounts reclassified from AOCI	0	0	0	0
Other comprehensive income (loss) attributable to UGI	(106)	16	(191)	23
Balance, end of period	(281)	(44)	(281)	(44)
Total
AOCI Attributable to Parent, Net of Tax
Balance, beginning of period	(178)	(126)	(140)	(147)
Balance, end of period	$ (273)	$ (105)	$ (273)	$ (105)