Condensed Financial Information of Registrant (Parent Company) (Details) (USD $) In Millions, except Share data, unless otherwise specified	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2009
Current assets:
Cash and cash equivalents	$ 319.9	$ 238.5	$ 260.7	$ 280.1
Deferred income taxes	56.8	44.9
Total current assets	1,504.5	1,306.1
Total assets	9,709.7	6,663.3	6,374.0
Current liabilities:
Derivative financial instruments	100.9	49.7
Total current liabilities	1,487.0	1,077.9
Commitments and contingencies (Note 1)
Common stockholders' equity:
Common Stock, without par value (authorized - 300,000,000 shares; issued - 115,624,594 and 115,507,094 shares, respectively)	1,157.7	937.4
Retained earnings	1,166.1	1,085.8
Accumulated other comprehensive loss	(62.0)	(17.7)
Treasury stock, at cost	(28.7)	(27.8)
Total UGI Corporation stockholders' equity	2,233.1	1,977.7
Total liabilities and equity	9,709.7	6,663.3
Condensed financial information of registrant (Textual) [Abstract]
UGI Common Stock, without par value	$ 0	$ 0
UGI Common Stock, without par value authorized	300,000,000	300,000,000
UGI Common Stock, without par value, issued	115,624,594	115,507,094	115,400,294	115,261,294
Parent Company [Member]
Current assets:
Cash and cash equivalents	1.9	0.4	1.0	1.4
Accounts and notes receivable	4.0	4.9
Deferred income taxes	0.4	0.4
Prepaid expenses and other current assets	0.3	1.4
Total current assets	6.6	7.1
Investments in subsidiaries	2,244.4	1,992.1
Deferred income taxes	28.3	22.3
Total assets	2,279.3	2,021.5
Current liabilities:
Accounts and notes payable	11.1	11.4
Derivative financial instruments	0	3.3
Accrued liabilities	2.4	1.7
Total current liabilities	13.5	16.4
Noncurrent liabilities	32.7	27.4
Commitments and contingencies (Note 1)
Common stockholders' equity:
Common Stock, without par value (authorized - 300,000,000 shares; issued - 115,624,594 and 115,507,094 shares, respectively)	1,157.7	937.4
Retained earnings	1,166.1	1,085.8
Accumulated other comprehensive loss	(62.0)	(17.7)
Treasury stock, at cost	(28.7)	(27.8)
Total UGI Corporation stockholders' equity	2,233.1	1,977.7
Total liabilities and equity	$ 2,279.3	$ 2,021.5