CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income including noncontrolling interests	$ 532	$ 308	$ 822
Net (losses) gains on derivative instruments (net of tax of $15, $3, and $(1), respectively)	(38)
Net (losses) gains on derivative instruments (net of tax of $15, $3, and $(1), respectively)		(7)	1
Reclassifications of net losses on derivative instruments (net of tax of $(4), $(2), and $(3), respectively)		2	4
Reclassifications of net losses on derivative instruments (net of tax of $(4), $(2), and $(3), respectively)	9
Foreign currency translation adjustments (net of tax of $12, $(13), and $(1), respectively)	15	(24)	(21)
Foreign currency gains (losses) on long-term intra-company transactions	84	(59)	(9)
Benefit plans, principally actuarial (losses) gains (net of tax of $1, $5, and $(5), respectively)	(3)	(13)	10
Reclassifications of benefit plans actuarial losses and net prior service benefit (net of tax of $(1), $(1), and $1, respectively)	3	1	(2)
Other comprehensive income (loss)	70	(100)	(17)
Comprehensive income including noncontrolling interests	602	208	805
Deduct comprehensive income attributable to noncontrolling interests, principally in AmeriGas Partners prior to the AmeriGas Merger	0	(52)	(103)
Comprehensive income attributable to UGI Corporation	$ 602	$ 156	$ 702