Segment Information - Reconciliation of Partnership Adjusted EBITDA (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Segment Reporting Information [Line Items]
Net gains (losses) on commodity derivative instruments not associated with current-period transactions			$ (1,866)	$ 372
Loss on extinguishments of debt	$ (9)	$ 0	(9)	(11)
Impairment of goodwill	(656)	0	(656)	0
Loss on disposal of U.K. energy marketing business	0	0	(215)	0
AmeriGas Propane
Segment Reporting Information [Line Items]
Impairment of goodwill	(656)
Corporate & Other
Segment Reporting Information [Line Items]
Loss on extinguishments of debt	(9)		(9)	(11)
Corporate & Other | AmeriGas Propane
Segment Reporting Information [Line Items]
Loss on extinguishments of debt	(9)		(9)	0
Impairment of goodwill	(656)		656
Loss on disposal of U.K. energy marketing business			0
Corporate & Other | AmeriGas Propane | Revenues
Segment Reporting Information [Line Items]
Net gains (losses) on commodity derivative instruments not associated with current-period transactions	0	0	0	0
Corporate & Other | AmeriGas Propane | Cost of sales
Segment Reporting Information [Line Items]
Net gains (losses) on commodity derivative instruments not associated with current-period transactions	(51)	(46)	(55)	(83)
Corporate & Other | 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	0
Corporate & Other | AmeriGas Propane | Operating and administrative expenses
Segment Reporting Information [Line Items]
AmeriGas operations enhancement for growth project	(6)		(19)
Restructuring costs		(1)		(15)
Impairment of assets			0
Corporate & Other | 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
Corporate & Other | AmeriGas Propane | Income (loss) from equity investees
Segment Reporting Information [Line Items]
Impairments associated with certain equity method investments		0		0
Corporate & Other | UGI International
Segment Reporting Information [Line Items]
Loss on extinguishments of debt	0		0	(11)
Impairment of goodwill	0		0
Loss on disposal of U.K. energy marketing business			(215)
Corporate & Other | UGI International | Revenues
Segment Reporting Information [Line Items]
Net gains (losses) on commodity derivative instruments not associated with current-period transactions	1	2	4	7
Corporate & Other | UGI International | Cost of sales
Segment Reporting Information [Line Items]
Net gains (losses) on commodity derivative instruments not associated with current-period transactions	(87)	110	(1,491)	458
Corporate & Other | 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)	6	(4)	6
Corporate & Other | UGI International | Operating and administrative expenses
Segment Reporting Information [Line Items]
AmeriGas operations enhancement for growth project	0		0
Restructuring costs		(2)		(4)
Impairment of assets			(19)
Corporate & Other | 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	(2)	14	(52)	19
Corporate & Other | UGI International | Income (loss) from equity investees
Segment Reporting Information [Line Items]
Impairments associated with certain equity method investments		0		0
Corporate & Other | Midstream & Marketing
Segment Reporting Information [Line Items]
Loss on extinguishments of debt	0		0	0
Impairment of goodwill	0		0
Loss on disposal of U.K. energy marketing business			0
Corporate & Other | Midstream & Marketing | Revenues
Segment Reporting Information [Line Items]
Net gains (losses) on commodity derivative instruments not associated with current-period transactions	1	(4)	7	(6)
Corporate & Other | Midstream & Marketing | Cost of sales
Segment Reporting Information [Line Items]
Net gains (losses) on commodity derivative instruments not associated with current-period transactions	(14)	(51)	(275)	(29)
Corporate & Other | 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	0
Corporate & Other | Midstream & Marketing | Operating and administrative expenses
Segment Reporting Information [Line Items]
AmeriGas operations enhancement for growth project	0		0
Restructuring costs		(1)		(1)
Impairment of assets			0
Corporate & Other | 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
Corporate & Other | Midstream & Marketing | Income (loss) from equity investees
Segment Reporting Information [Line Items]
Impairments associated with certain equity method investments		$ (50)		$ (50)