Segment Information - Reconciliation of Partnership Adjusted EBITDA (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Segment Reporting Information [Line Items]
Net gains on commodity derivative instruments not associated with current-period transactions	$ (141)	$ (1,402)
Costs associated with exit of the UGI International energy marketing business	(28)	(215)
Midstream & Marketing
Segment Reporting Information [Line Items]
Costs associated with exit of the UGI International energy marketing business		0
Midstream & Marketing | Revenues
Segment Reporting Information [Line Items]
Net gains on commodity derivative instruments not associated with current-period transactions	1	2
Costs associated with exit of the UGI International energy marketing business	0
Midstream & Marketing | Cost of sales
Segment Reporting Information [Line Items]
Net gains on commodity derivative instruments not associated with current-period transactions	(47)	(183)
Midstream & Marketing | Other operating income, net
Segment Reporting Information [Line Items]
Net gains on commodity derivative instruments not associated with current-period transactions	0	0
Midstream & Marketing | Other non-operating expense, net
Segment Reporting Information [Line Items]
Net gains on commodity derivative instruments not associated with current-period transactions	0	0
Midstream & Marketing | Operating and administrative expenses
Segment Reporting Information [Line Items]
AmeriGas operations enhancement for growth project	0	0
Costs associated with exit of the UGI International energy marketing business		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
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
UGI International
Segment Reporting Information [Line Items]
Costs associated with exit of the UGI International energy marketing business		(215)
UGI International | Revenues
Segment Reporting Information [Line Items]
Net gains on commodity derivative instruments not associated with current-period transactions	1	2
Costs associated with exit of the UGI International energy marketing business	(42)
UGI International | Cost of sales
Segment Reporting Information [Line Items]
Net gains on commodity derivative instruments not associated with current-period transactions	(41)	(1,169)
UGI International | Other operating income, net
Segment Reporting Information [Line Items]
Net gains on commodity derivative instruments not associated with current-period transactions	(3)	(2)
UGI International | Other non-operating expense, net
Segment Reporting Information [Line Items]
Net gains on commodity derivative instruments not associated with current-period transactions	(20)	(40)
UGI International | Operating and administrative expenses
Segment Reporting Information [Line Items]
AmeriGas operations enhancement for growth project	0	0
Costs associated with exit of the UGI International energy marketing business		(19)
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	(8)
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	(28)
AmeriGas Propane
Segment Reporting Information [Line Items]
Costs associated with exit of the UGI International energy marketing business		0
AmeriGas Propane | Revenues
Segment Reporting Information [Line Items]
Net gains on commodity derivative instruments not associated with current-period transactions	0	0
Costs associated with exit of the UGI International energy marketing business	0
AmeriGas Propane | Cost of sales
Segment Reporting Information [Line Items]
Net gains on commodity derivative instruments not associated with current-period transactions	(6)	(12)
AmeriGas Propane | Other operating income, net
Segment Reporting Information [Line Items]
Net gains on commodity derivative instruments not associated with current-period transactions	0	0
AmeriGas Propane | Other non-operating expense, net
Segment Reporting Information [Line Items]
Net gains on commodity derivative instruments not associated with current-period transactions	0	0
AmeriGas Propane | Operating and administrative expenses
Segment Reporting Information [Line Items]
AmeriGas operations enhancement for growth project	(7)	(7)
Costs associated with exit of the UGI International energy marketing business		$ 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
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