Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Statement of Comprehensive Income [Abstract]
Net income including noncontrolling interests	$ 523.8	$ 488.8	$ 414.0
Net gains (losses) on derivative instruments (net of tax of $(0.5), $12.3 and $(8.0), respectively)	1.7	(16.5)	16.8
Reclassifications of net (gains) losses on derivative instruments (net of tax of $4.1, $5.0 and $(2.8), respectively)	(9.7)	(8.1)	1.6
Foreign currency translation adjustments (net of tax of $(0.6), $0.0 and $(1.0), respectively)	34.6	(4.9)	(63.5)
Foreign currency gains (losses) on long-term intra-company transactions (net of tax of $0.0, $0.0 and $(6.7), respectively)	24.8	(1.9)	(50.6)
Benefit plans, principally actuarial gains (losses) (net of tax of $(3.8), $7.1 and $1.4, respectively)	6.5	(10.9)	(1.2)
Reclassifications of benefit plans actuarial losses and net prior service credits (net of tax of $(2.1), $(0.4) and $(0.8), respectively)	3.4	2.2	1.4
Other comprehensive income (loss)	61.3	(40.1)	(95.5)
Comprehensive income including noncontrolling interests	585.1	448.7	318.5
Deduct comprehensive income attributable to noncontrolling interests, principally in AmeriGas Partners	(87.2)	(124.1)	(130.9)
Comprehensive income attributable to UGI Corporation	$ 497.9	$ 324.6	$ 187.6