Employee Retirement Plans - Fair Value of U.S. Pension Plan and VEBA Trust Assets (Details) - Pension Benefits - USD ($) $ in Millions	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 541	$ 736	$ 585
U.S.
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	525	717
U.S. | U.S. equities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	26	35
U.S. | UGI Corporation Common Stock
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	26	35
U.S. | Total common collective trust funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	482	655
U.S. | U.S. equity index investments
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	113	124
U.S. | Non-U.S. equity index investments
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	110	155
U.S. | Global equity index investments
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	72	115
U.S. | Bond index mutual funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	177	254
U.S. | Cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	10	7
U.S. | Alternative investments
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 17	$ 27