Employee Retirement Plans (Details Textual) In Millions, unless otherwise specified	12 Months Ended					3 Months Ended		12 Months Ended
	Sep. 30, 2012 USD ($)	Sep. 30, 2011 USD ($)	Sep. 30, 2010 USD ($)	Sep. 30, 2009 USD ($)	Sep. 30, 2011 Plan Merger [Member] Other Pension Plans Postretirement Or Supplemental Plans Defined Benefit [Member] USD ($)	Dec. 31, 2011 Pension Benefit [Member]	Dec. 31, 2010 Pension Benefit [Member]	Sep. 30, 2011 Pension Benefit [Member] USD ($)	Sep. 30, 2010 Pension Benefit [Member] USD ($)	Sep. 30, 2009 Pension Benefit [Member] USD ($)	Sep. 30, 2008 Pension Benefit [Member]	Sep. 30, 2011 Other Postretirement Benefits [Member] USD ($)	Sep. 30, 2010 Other Postretirement Benefits [Member] USD ($)	Sep. 30, 2009 Other Postretirement Benefits [Member] USD ($)	Sep. 30, 2009 Other Postretirement Benefits [Member] EUR (€)	Sep. 30, 2008 Other Postretirement Benefits [Member]	Sep. 30, 2011 Maximum [Member]	Sep. 30, 2011 Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Decrease in Other Noncurrent liabilities, as a result of the merger					$ 46.7
Decrease in Associated Regulatory Assets, as a result of the merger					43.1
Increase in pre-tax other comprehensive income, as a result of merger					3.6
Discount rate						5.50%	5.00%	5.30%	5.00%	5.50%	6.80%	5.30%	5.00%	5.50%	5.50%	6.80%
ABO for the Pension Plans								415.0	417.8
Contribution made to Pension Plan								19.2	3.4	0		1.1	1.0
Settlement of obligation under retirement benefit plan									(2.7)			18.7		5.7	4.1
Expected contribution to pensions plans in next twelve months								27.6
Assumed domestic health care cost range																	7.50%	5.00%
Defined Benefit Pension and Other Postretirement Plans (Textual) [Abstract]
Amortization of net actuarial losses		8.8
Amortization of prior service credits		0.2
Projected benefit obligations of unfunded and non qualified supplemental executive retirement plans		25.6	23.9
Net cost to sponsor unfunded and non-qualified supplemental executive retirement plans		3.0	2.6	3.1
Amounts recorded in UGI's stockholders include pre-tax losses representing unrecognized actuarial losses		7.6	4.7					(13.6)	(13.8)			0.8	(0.1)
Amount of expected amortization of pre-tax actuarial losses into retiree benefit cost	0.7
The aggregate holdings of all qualifying employer securities not to exceed the fair value of trust assets at the time of purchase		10.00%
Percentage of UGI Common Stock represented Pension Plan Assets		7.60%	8.30%
Cost of benefits under the 401(k) savings plan		$ 10.4	$ 9.8	$ 10.1