Goodwill and Intangible Assets - Narrative (Details) - USD ($)	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022	Jun. 30, 2023
Goodwill [Line Items]
Impairment of goodwill	$ 195,000,000	$ 656,000,000	$ 0
Goodwill	2,871,000,000	3,027,000,000	3,612,000,000
Amortization expense of intangible assets	55,000,000	56,000,000	61,000,000
Fiscal 2025	52,000,000
Fiscal 2026	50,000,000
Fiscal 2027	27,000,000
Fiscal 2028	17,000,000
Fiscal 2029	16,000,000
Customer relationships
Goodwill [Line Items]
Impairment of customer relationship intangible		10,000,000
AmeriGas Propane
Goodwill [Line Items]
Impairment of goodwill	195,000,000	656,000,000
Goodwill	$ 1,153,000,000	$ 1,348,000,000	$ 2,004,000,000
Senior Notes Due 2028 | Senior Notes | AmeriGas Partners and AmeriGas Finance Corp.
Goodwill [Line Items]
Principal amount				$ 500,000,000
Interest rate (as a percentage)				9.375%