Quarterly Data (unaudited) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Quarterly Financial Data [Abstract]
Revenues	$ 1,113.9	$ 1,153.5	$ 2,173.8	$ 1,679.5	$ 976.2	$ 1,130.8	$ 1,972.1	$ 1,606.6	$ 6,120.7	$ 5,685.7	$ 6,691.1
Operating income (loss)	27.6	(2.8)	513.2	466.2	(88.6)	155.7	615.4	305.5	1,004.2	988.0	834.9
(Loss) income from equity investees	1.3	0.9	2.3	(0.2)	(0.1)	0.0	0.0	(0.1)	4.3	(0.2)	(1.2)
Loss on extinguishments of debt	0.0	(4.4)	(22.1)	(33.2)	(11.8)	(37.1)	0.0	0.0	(59.7)	(48.9)	0.0
Net income (loss) including noncontrolling interests	(16.7)	(62.2)	311.8	290.9	(115.7)	28.6	408.0	167.9	523.8	488.8	414.0
Net income (loss) attributable to UGI Corporation	$ 5.0	$ (19.0)	$ 219.9	$ 230.7	$ (43.8)	$ 60.7	$ 233.2	$ 114.6	$ 436.6	$ 364.7	$ 281.0
Earnings (loss) per common share attributable to UGI Corporation stockholders:
Basic (in dollars per share)	$ 0.03	$ (0.11)	$ 1.27	$ 1.33	$ (0.25)	$ 0.35	$ 1.35	$ 0.66	$ 2.51	$ 2.11	$ 1.62
Diluted (in dollars per share)	$ 0.03	$ (0.11)	$ 1.24	$ 1.30	$ (0.25)	$ 0.34	$ 1.33	$ 0.65	$ 2.46	$ 2.08	$ 1.60
Effect of Fourth Quarter Events [Line Items]
Increase in net income attributable to UGI Corporation, income tax settlement refund				$ 6.7
Increase in net income attributable to UGI Corporation, income tax settlement refund (in dollars per share)				$ 0.04
Increase in net income attributable to UGI Corporation due to release of valuation allowance against future uses of foreign tax credit carryforwards	$ 7.6								$ (7.2)
Increase in net income per diluted share due to release of valuation allowance against future uses of foreign tax credit carryforwards (in dollars per share)	$ 0.04
Increase (decrease) in net income (loss) attributable to UGI Corporation, loss on extinguishments of debt		$ (0.7)	$ (3.6)	$ (5.3)	$ (1.8)	$ (6.1)
Increase (decrease) in net income (loss) attributable to UGI Corporation, loss on extinguishments of debt (in dollars per share)		$ (0.01)	$ (0.02)	$ (0.03)	$ (0.01)	$ (0.03)
Decrease in net income attributable to UGI Corporation, impairment of cost basis investment	$ 2.6		$ 4.5
Decrease in net income attributable to UGI Corporation, impairment of cost basis investment (in dollars per share)	$ 0.02		$ 0.03
UGI France
Effect of Fourth Quarter Events [Line Items]
Increase in net income attributable to UGI Corporation, adjustments to net deferred income tax liabilities				$ 27.4
Increase in net income attributable to UGI Corporation, adjustments to net deferred income tax liabilities (in dollars per share)				$ 0.15