CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2021	Sep. 30, 2020	Mar. 31, 2020
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 52	$ 42	$ 39
Accumulated depreciation	$ 3,869	$ 3,698	$ 3,555
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	209,636,619	209,514,044	209,439,475