Segment Information - Reconciliation of Partnership Adjusted EBITDA (Details) - USD ($) $ in Millions	3 Months Ended
Dec. 31, 2022	Dec. 31, 2021
Segment Reporting Information [Line Items]
Net gains (losses) on commodity derivative instruments not associated with current-period transactions	$ (1,402)	$ (397)
Impairment of assets	(19)	0
Loss on extinguishments of debt	0	(11)
AmeriGas Propane
Segment Reporting Information [Line Items]
Loss on extinguishments of debt		0
AmeriGas Propane \| Revenues
Segment Reporting Information [Line Items]
Net gains (losses) on commodity derivative instruments not associated with current-period transactions	0	0
AmeriGas Propane \| Cost of sales
Segment Reporting Information [Line Items]
Net gains (losses) on commodity derivative instruments not associated with current-period transactions	(12)	(69)
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
AmeriGas Propane \| Other non-operating (expense) income, net
Segment Reporting Information [Line Items]
Net gains (losses) 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)
Impairment of assets	0
AmeriGas Propane \| Loss on disposal of U.K. energy marketing business
Segment Reporting Information [Line Items]
Loss on disposal of U.K. energy marketing business	0
UGI International
Segment Reporting Information [Line Items]
Loss on extinguishments of debt		(11)
UGI International \| Revenues
Segment Reporting Information [Line Items]
Net gains (losses) on commodity derivative instruments not associated with current-period transactions	2	3
UGI International \| Cost of sales
Segment Reporting Information [Line Items]
Net gains (losses) on commodity derivative instruments not associated with current-period transactions	(1,169)	(212)
UGI International \| Other operating income, net
Segment Reporting Information [Line Items]
Net gains (losses) on commodity derivative instruments not associated with current-period transactions	(2)
UGI International \| Other non-operating (expense) income, net
Segment Reporting Information [Line Items]
Net gains (losses) on commodity derivative instruments not associated with current-period transactions	(40)	6
UGI International \| Operating and administrative expenses
Segment Reporting Information [Line Items]
AmeriGas operations enhancement for growth project	0
Impairment of assets	(19)
UGI International \| Loss on disposal of U.K. energy marketing business
Segment Reporting Information [Line Items]
Loss on disposal of U.K. energy marketing business	(215)
Midstream & Marketing
Segment Reporting Information [Line Items]
Loss on extinguishments of debt		0
Midstream & Marketing \| Revenues
Segment Reporting Information [Line Items]
Net gains (losses) on commodity derivative instruments not associated with current-period transactions	2	7
Midstream & Marketing \| Cost of sales
Segment Reporting Information [Line Items]
Net gains (losses) on commodity derivative instruments not associated with current-period transactions	(183)	(132)
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
Midstream & Marketing \| Other non-operating (expense) income, net
Segment Reporting Information [Line Items]
Net gains (losses) 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
Impairment of assets	0
Midstream & Marketing \| Loss on disposal of U.K. energy marketing business
Segment Reporting Information [Line Items]
Loss on disposal of U.K. energy marketing business	$ 0

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