Debt - Schedule of Short-term Debt (Footnotes) (Details)	1 Months Ended	12 Months Ended
	Oct. 31, 2020 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2020 EUR (€)	Sep. 30, 2019 EUR (€)
Short-term Debt [Line Items]
Repayment of debt		$ 86,000,000	$ 738,000,000	$ 149,000,000
AmeriGas OLP
Short-term Debt [Line Items]
Maximum borrowing capacity		600,000,000	600,000,000
Borrowing		186,000,000	328,000,000
AmeriGas OLP | Letter of Credit | 2019 Credit Agreement | Line of Credit
Short-term Debt [Line Items]
Maximum borrowing capacity		150,000,000
UGI International LLC
Short-term Debt [Line Items]
Maximum borrowing capacity | €					€ 300,000,000	€ 300,000,000
Borrowing			210,000,000		€ 0	€ 193,000,000
Energy Services
Short-term Debt [Line Items]
Maximum borrowing capacity		260,000,000	200,000,000
Borrowing		0	45,000,000
Energy Services | Letter of Credit | 2019 Credit Agreement | Line of Credit
Short-term Debt [Line Items]
Maximum borrowing capacity		50,000,000
UGI Utilities
Short-term Debt [Line Items]
Maximum borrowing capacity		350,000,000	350,000,000
Borrowing		141,000,000	166,000,000
UGI Utilities | Letter of Credit | 2019 Credit Agreement | Line of Credit
Short-term Debt [Line Items]
Maximum borrowing capacity		100,000,000
UGI Corporation
Short-term Debt [Line Items]
Maximum borrowing capacity		300,000,000	300,000,000
Borrowing		300,000,000	$ 300,000,000
UGI Corporation | Subsequent Event
Short-term Debt [Line Items]
Repayment of debt	$ 30,000,000
UGI Corporation | Letter of Credit | 2019 Credit Agreement | The UGI Corporation Senior Credit Facility
Short-term Debt [Line Items]
Maximum borrowing capacity		$ 10,000,000