Condensed Consolidated Balance Sheets (unaudited) (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Accounts receivable, allowances for doubtful accounts	$ 35.1	$ 26.9	$ 29.2
Property, plant and equipment, accumulated depreciation and amortization	$ 3,393.1	$ 3,312.9	$ 3,139.8
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	173,997,441	173,987,691	173,903,191