Segment Information - Reconciliation of Partnership EBITDA to AmeriGas Propane Operating Income and Footnotes (Details) - USD ($)	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
Reconciliation of partnership EBITDA
Depreciation and amortization									$ (416,300,000)	$ (400,900,000)	$ (374,100,000)
Interest expense									(223,500,000)	(228,900,000)	(241,900,000)
Loss on extinguishments of debt	$ 0	$ (4,400,000)	$ (22,100,000)	$ (33,200,000)	$ (11,800,000)	$ (37,100,000)	$ 0	$ 0	(59,700,000)	(48,900,000)	0
Income before income taxes									$ 701,400,000	$ 710,000,000	$ 591,800,000
General Partner interest in AmeriGas OLP (percentage)									1.01%	1.01%	1.01%
Pretax gains (losses) on unsettled commodity derivative instruments									$ 82,000,000	$ 91,600,000	$ (119,100,000)
Other-than-temporary impairment of an investment in a private equity partnership pre-tax loss									11,000,000	0	0
UGI International | Term Loan
Reconciliation of partnership EBITDA
Pretax loss on early extinguishment of debt											10,300,000
Operating Segments | AmeriGas Propane
Reconciliation of partnership EBITDA
Partnership Adjusted EBITDA									551,300,000	543,000,000	619,200,000
Depreciation and amortization									(190,500,000)	(190,000,000)	(194,900,000)
Interest expense									(160,200,000)	(164,100,000)	(162,800,000)
Loss on extinguishments of debt									(59,700,000)	(48,900,000)	0
MGP environmental accrual									(7,500,000)	0	0
Noncontrolling interests									2,000,000	3,300,000	3,300,000
Income before income taxes									135,400,000	143,300,000	264,800,000
Operating Segments | UGI International
Reconciliation of partnership EBITDA
Depreciation and amortization									(117,400,000)	(112,400,000)	(86,900,000)
Interest expense									(20,600,000)	(24,400,000)	(35,200,000)
Loss on extinguishments of debt									0	0
Income before income taxes									$ 175,000,000	$ 182,000,000	$ 76,400,000