CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	Jun. 30, 2021	Sep. 30, 2020	Jun. 30, 2020
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 51	$ 42	$ 42
Accumulated depreciation	$ 3,923	$ 3,698	$ 3,600
UGI Preferred Stock, without par value, shares authorized	5,000,000	5,000,000	5,000,000
UGI Preferred Stock, without par value, shares issued	220,000	0	0
UGI Common Stock, without par value, shares authorized	450,000,000	450,000,000	450,000,000
UGI Common Stock, without par value, shares issued	209,725,554	209,514,044	209,504,994