Segment Information - Reconciliation of Partnership Adjusted EBITDA (Details) - USD ($) $ in Millions	3 Months Ended
Dec. 31, 2021	Dec. 31, 2020
Segment Reporting Information [Line Items]
Net gains (losses) on commodity derivative instruments not associated with current-period transactions	$ (397)	$ 96
Loss on extinguishment of debt	(11)	0
AmeriGas Propane
Segment Reporting Information [Line Items]
Loss on extinguishment 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	(69)	37
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
AmeriGas Propane \| Operating and administrative expenses
Segment Reporting Information [Line Items]
Business transformation expenses		(12)
UGI International
Segment Reporting Information [Line Items]
Loss on extinguishment of debt	(11)
UGI International \| Revenues
Segment Reporting Information [Line Items]
Net gains (losses) on commodity derivative instruments not associated with current-period transactions	3	0
UGI International \| Cost of sales
Segment Reporting Information [Line Items]
Net gains (losses) on commodity derivative instruments not associated with current-period transactions	(212)	106
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	6	(20)
UGI International \| Operating and administrative expenses
Segment Reporting Information [Line Items]
Business transformation expenses		(3)
Midstream & Marketing
Segment Reporting Information [Line Items]
Loss on extinguishment of debt	0
Midstream & Marketing \| Revenues
Segment Reporting Information [Line Items]
Net gains (losses) on commodity derivative instruments not associated with current-period transactions	7	2
Midstream & Marketing \| Cost of sales
Segment Reporting Information [Line Items]
Net gains (losses) on commodity derivative instruments not associated with current-period transactions	(132)	(29)
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
Midstream & Marketing \| Operating and administrative expenses
Segment Reporting Information [Line Items]
Business transformation expenses		$ 0

Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity.

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