CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Statement of Comprehensive Income [Abstract]
Net income including noncontrolling interests	$ 1,467	$ 532	$ 308
Net gains (losses) on derivative instruments (net of tax of $(1), $15, and $3, respectively)	3	(38)	(7)
Reclassifications of net losses on derivative instruments (net of tax of $(7), $(4), and $(2), respectively)	18	9	2
Foreign currency translation adjustments (net of tax of $(4), $12, and $(13), respectively)	(11)	15	(24)
Foreign currency (losses) gains on long-term intra-company transactions	(12)	84	(59)
Benefit plans, principally actuarial gains (losses) (net of tax of $(3), $1, and $5, respectively)	7	(3)	(13)
Reclassifications of benefit plans actuarial losses and net prior service benefit (net of tax of $(1), $(1), and $(1), respectively)	2	3	1
Other comprehensive income (loss)	7	70	(100)
Comprehensive income including noncontrolling interests	1,474	602	208
Deduct comprehensive income attributable to noncontrolling interests, principally in AmeriGas Partners prior to the AmeriGas Merger	0	0	(52)
Comprehensive income attributable to UGI Corporation	$ 1,474	$ 602	$ 156