Segment Information - Reconciliation of Partnership Adjusted EBITDA (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Sep. 30, 2023
Segment Reporting Information [Line Items]
Net gains (losses) on commodity derivative instruments not associated with current-period transactions			$ (12)	$ (1,866)
Loss on extinguishments of debt	$ (7)	$ (9)	(7)	(9)
Impairment of held-for-sale assets	(62)	0	(62)	0
Loss on disposal of UGI International energy marketing business	(1)	0	(29)	(215)
Loss associated with impairment of AmeriGas Propane goodwill	0	(656)	0	(656)
Corporate & Other
Segment Reporting Information [Line Items]
Loss on extinguishments of debt	(7)	(9)	(7)	(9)
Midstream & Marketing | Corporate & Other
Segment Reporting Information [Line Items]
Loss on extinguishments of debt	(1)	0	(1)	0
Loss associated with impairment of AmeriGas Propane goodwill	0			0
Midstream & Marketing | Revenues
Segment Reporting Information [Line Items]
Net gains (losses) on commodity derivative instruments not associated with current-period transactions		1	0	7
Costs associated with exit of the UGI International energy marketing business			0
Midstream & Marketing | Revenues | Corporate & Other
Segment Reporting Information [Line Items]
Net gains (losses) on commodity derivative instruments not associated with current-period transactions	(1)
Midstream & Marketing | Cost of sales
Segment Reporting Information [Line Items]
Net gains (losses) on commodity derivative instruments not associated with current-period transactions	26	(14)	20	(275)
Midstream & Marketing | Other operating income, net
Segment Reporting Information [Line Items]
Net gains (losses) on commodity derivative instruments not associated with current-period transactions		0	0	0
Impairment of assets			0
Midstream & Marketing | Operating and administrative expenses
Segment Reporting Information [Line Items]
Restructuring costs	0		0
AmeriGas operations enhancement for growth project	0	0	0	0
Costs associated with exit of the UGI International energy marketing business				0
Midstream & Marketing | Other non-operating income (expense), net
Segment Reporting Information [Line Items]
Net gains (losses) on commodity derivative instruments not associated with current-period transactions	0	0	0	0
Midstream & Marketing | Operating and administrative expenses/Other operating income, net
Segment Reporting Information [Line Items]
Costs associated with exit of the UGI International energy marketing business	0		0
Midstream & Marketing | Loss on disposal of UGI International energy marketing business
Segment Reporting Information [Line Items]
Costs associated with exit of the UGI International energy marketing business	0		0	0
Midstream & Marketing | Impairment of held-for-sale assets
Segment Reporting Information [Line Items]
Impairment of held-for-sale assets	(62)		(62)
Midstream & Marketing | (Loss) income from equity investees
Segment Reporting Information [Line Items]
Impairment associated with equity method investments	0		0
UGI International | Corporate & Other
Segment Reporting Information [Line Items]
Loss on extinguishments of debt	0	0	0	0
Loss associated with impairment of AmeriGas Propane goodwill	0			0
UGI International | Revenues
Segment Reporting Information [Line Items]
Net gains (losses) on commodity derivative instruments not associated with current-period transactions		1	1	4
Costs associated with exit of the UGI International energy marketing business			(42)
UGI International | Revenues | Corporate & Other
Segment Reporting Information [Line Items]
Net gains (losses) on commodity derivative instruments not associated with current-period transactions	0
UGI International | Cost of sales
Segment Reporting Information [Line Items]
Net gains (losses) on commodity derivative instruments not associated with current-period transactions	20	(87)	32	(1,491)
UGI International | Other operating income, net
Segment Reporting Information [Line Items]
Net gains (losses) on commodity derivative instruments not associated with current-period transactions		(1)	(2)	(4)
Impairment of assets			(7)
UGI International | Operating and administrative expenses
Segment Reporting Information [Line Items]
Restructuring costs	(4)		(38)
AmeriGas operations enhancement for growth project	0	0	0	0
Costs associated with exit of the UGI International energy marketing business				(19)
UGI International | Other non-operating income (expense), net
Segment Reporting Information [Line Items]
Net gains (losses) on commodity derivative instruments not associated with current-period transactions	1	(2)	(18)	(52)
UGI International | Operating and administrative expenses/Other operating income, net
Segment Reporting Information [Line Items]
Costs associated with exit of the UGI International energy marketing business	(1)		(11)
UGI International | Loss on disposal of UGI International energy marketing business
Segment Reporting Information [Line Items]
Costs associated with exit of the UGI International energy marketing business	(1)		(29)	(215)
UGI International | Impairment of held-for-sale assets
Segment Reporting Information [Line Items]
Impairment of held-for-sale assets	0		0
UGI International | (Loss) income from equity investees
Segment Reporting Information [Line Items]
Impairment associated with equity method investments	(25)		(25)
AmeriGas Propane
Segment Reporting Information [Line Items]
Loss associated with impairment of AmeriGas Propane goodwill					$ (656)
AmeriGas Propane | Corporate & Other
Segment Reporting Information [Line Items]
Loss on extinguishments of debt	(6)	(9)	(6)	(9)
Loss associated with impairment of AmeriGas Propane goodwill	(656)			(656)
AmeriGas Propane | Revenues
Segment Reporting Information [Line Items]
Net gains (losses) on commodity derivative instruments not associated with current-period transactions		0	0	0
Costs associated with exit of the UGI International energy marketing business			0
AmeriGas Propane | Revenues | Corporate & Other
Segment Reporting Information [Line Items]
Net gains (losses) on commodity derivative instruments not associated with current-period transactions	0
AmeriGas Propane | Cost of sales
Segment Reporting Information [Line Items]
Net gains (losses) on commodity derivative instruments not associated with current-period transactions	3	(51)	31	(55)
AmeriGas Propane | Other operating income, net
Segment Reporting Information [Line Items]
Net gains (losses) on commodity derivative instruments not associated with current-period transactions		0	0	0
Impairment of assets			0
AmeriGas Propane | Operating and administrative expenses
Segment Reporting Information [Line Items]
Restructuring costs	(2)		(2)
AmeriGas operations enhancement for growth project	(12)	(6)	(25)	(19)
Costs associated with exit of the UGI International energy marketing business				0
AmeriGas Propane | Other non-operating income (expense), net
Segment Reporting Information [Line Items]
Net gains (losses) on commodity derivative instruments not associated with current-period transactions	0	$ 0	0	0
AmeriGas Propane | Operating and administrative expenses/Other operating income, net
Segment Reporting Information [Line Items]
Costs associated with exit of the UGI International energy marketing business	0		0
AmeriGas Propane | Loss on disposal of UGI International energy marketing business
Segment Reporting Information [Line Items]
Costs associated with exit of the UGI International energy marketing business	0		0	$ 0
AmeriGas Propane | Impairment of held-for-sale assets
Segment Reporting Information [Line Items]
Impairment of held-for-sale assets	0		0
AmeriGas Propane | (Loss) income from equity investees
Segment Reporting Information [Line Items]
Impairment associated with equity method investments	$ 0		$ 0