Debt - Schedule of Long-term Debt (Footnotes) (Details) - USD ($)	12 Months Ended
Sep. 30, 2021	Sep. 30, 2020
Debt Instrument [Line Items]
Long-term debt	$ 6,449,000,000	$ 6,034,000,000
Senior Secured Notes \| Mountaineer senior notes
Debt Instrument [Line Items]
Long-term debt	140,000,000
Unamortized premium	$ 24,000,000
Senior Secured Notes \| Mountaineer senior notes \| Minimum
Debt Instrument [Line Items]
Stated interest rate (as a percentage)	3.50%
Senior Secured Notes \| Mountaineer senior notes \| Maximum
Debt Instrument [Line Items]
Stated interest rate (as a percentage)	4.41%
AmeriGas Propane
Debt Instrument [Line Items]
Long-term debt	$ 2,560,000,000	2,560,000,000
UGI International
Debt Instrument [Line Items]
Long-term debt	$ 770,000,000	$ 778,000,000
UGI International \| Term Loan \| Variable-rate term loan
Debt Instrument [Line Items]
Effective interest rate (as a percentage)	1.89%	2.04%
Midstream & Marketing
Debt Instrument [Line Items]
Long-term debt	$ 716,000,000	$ 720,000,000
Midstream & Marketing \| Term Loan \| Variable-rate term loan
Debt Instrument [Line Items]
Effective interest rate (as a percentage)	5.23%	5.30%
Quarterly Installments	$ 2,000,000
UGI Utilities
Debt Instrument [Line Items]
Long-term debt	$ 1,451,000,000	$ 1,121,000,000
Weighted Average Interest Rate - End of Year	1.35%	1.12%
UGI Utilities \| Term Loan \| Variable-rate term loan
Debt Instrument [Line Items]
Effective interest rate (as a percentage)	4.00%	4.00%
Quarterly Installments	$ 2,000,000
UGI Corporation
Debt Instrument [Line Items]
Long-term debt	$ 945,000,000	$ 847,000,000
Weighted Average Interest Rate - End of Year		2.41%
UGI Corporation \| Term Loan \| 3-year Term loan
Debt Instrument [Line Items]
Effective interest rate (as a percentage)	3.26%	3.51%
UGI Corporation \| Term Loan \| 5-year Term Loan
Debt Instrument [Line Items]
Effective interest rate (as a percentage)	3.56%	3.50%
Quarterly Installments	$ 9,000,000
UGI Corporation \| Term Loan \| 7-Year Term Loan
Debt Instrument [Line Items]
Effective interest rate (as a percentage)	1.88%
UGI Corporation \| Line of Credit
Debt Instrument [Line Items]
Effective interest rate (as a percentage)	3.27%	2.41%
Weighted Average Interest Rate - End of Year	3.27%

Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

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Contractual interest rate for funds borrowed, under the debt agreement.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount of the required periodic payments applied to principal.

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Amount, after accumulated amortization, of debt premium.

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- Definition

The effective interest rate at the end of the reporting period.

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- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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