CONDENSED CONSOLIDATED BALANCE SHEETS (unaudited) (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2019	Sep. 30, 2018	Mar. 31, 2018
Statement of Financial Position [Abstract]
Accounts receivable, allowances for doubtful accounts	$ 43.6	$ 35.1	$ 44.6
Property, plant and equipment, accumulated depreciation and amortization	$ 3,274.6	$ 3,153.9	$ 3,141.2
UGI Common Stock, without par value, shares authorized (in shares)	450,000,000	450,000,000	450,000,000
UGI Common Stock, without par value, shares issued (in shares)	174,596,873	174,142,997	174,015,641