Condensed Consolidated Balance Sheets (unaudited) (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2018	Sep. 30, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Accounts receivable, allowances for doubtful accounts	$ 38.5	$ 35.1	$ 35.1
Property, plant and equipment, accumulated depreciation and amortization	$ 3,228.3	$ 3,153.9	$ 3,393.1
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)	174,262,763	174,142,997	173,997,441