CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Thousands, $ in Millions	3 Months Ended								12 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Income Statement [Abstract]
Revenues	$ 1,150.4	$ 1,363.7	$ 2,606.1	$ 2,200.2	$ 1,273.1	$ 1,440.9	$ 2,812.0	$ 2,125.2	$ 7,320.4	$ 7,651.2	$ 6,120.7
Costs and expenses:
Cost of sales (excluding depreciation and amortization shown below)									4,323.1	4,074.9	2,837.3
Operating and administrative expenses									1,963.2	2,012.8	1,867.6
Impairment of Partnership tradenames and trademarks									0.0	75.0	0.0
Depreciation and amortization									448.1	455.1	416.3
Other operating income, net									(31.1)	(31.3)	(10.5)
Total costs and expenses									6,703.3	6,586.5	5,110.7
Operating income	(99.0)	9.6	538.8	167.7	49.2	29.5	591.0	395.0	617.1	1,064.7	1,010.0
Income from equity investees									9.1	4.3	4.3
Loss on extinguishments of debt				(4.2)					(6.1)	0.0	(59.7)
Other non-operating income (expense), net									38.2	15.6	(29.7)
Interest expense									(257.8)	(230.1)	(223.5)
Income before income taxes									400.5	854.5	701.4
Income tax expense									(92.6)	(32.1)	(177.6)
Net income including noncontrolling interests	(130.8)	(46.5)	396.7	88.5	(7.8)	(11.7)	407.7	434.2	307.9	822.4	523.8
Deduct net income attributable to noncontrolling interests, principally in AmeriGas Partners									(51.7)	(103.7)	(87.2)
Net income attributable to UGI Corporation	$ (51.5)	$ (1.9)	$ 245.4	$ 64.2	$ 24.4	$ 52.4	$ 276.0	$ 365.9	$ 256.2	$ 718.7	$ 436.6
Earnings per common share attributable to UGI Corporation stockholders:
Basic (in dollars per share)	$ (0.27)	$ (0.01)	$ 1.41	$ 0.37	$ 0.14	$ 0.30	$ 1.59	$ 2.11	$ 1.44	$ 4.13	$ 2.51
Diluted (in dollars per share)	$ (0.27)	$ (0.01)	$ 1.38	$ 0.36	$ 0.14	$ 0.30	$ 1.57	$ 2.07	$ 1.41	$ 4.06	$ 2.46
Weighted-average common shares outstanding:
Basic (in shares)	189,905	174,759	174,501	174,413	174,391	173,991	173,570	173,670	178,417	173,908	173,662
Diluted (in shares)	189,905	174,759	177,318	177,566	177,506	176,807	176,350	176,948	181,111	176,905	177,159
Dividends declared per common share (in dollars per share)									$ 1.145	$ 1.02	$ 0.975