Disclosures About Derivative Instruments and Hedging Activities (Details Textual)	1 Months Ended	3 Months Ended	12 Months Ended					3 Months Ended																				12 Months Ended						12 Months Ended
	Aug. 31, 2011 USD ($)	Sep. 30, 2011 USD ($)	Sep. 30, 2011 USD ($) States Year bcf	Sep. 30, 2010 USD ($)	Sep. 30, 2009 USD ($)	Sep. 30, 2011 Gas Utility [Member] DTH	Sep. 30, 2010 Gas Utility [Member] DTH	Mar. 31, 2010 AmeriGas Propane [Member] USD ($)	Sep. 30, 2011 Electric Utility - Forward Contract [Member] USD ($) Kilowatt-hour	Sep. 30, 2010 Electric Utility - Forward Contract [Member] USD ($) Kilowatt-hour	Sep. 30, 2011 Midstream And Marketing Natural Gas [Member] DTH	Sep. 30, 2011 Midstream And Marketing Propane Storage [Member] gal	Sep. 30, 2011 LPG [Member] gal	Sep. 30, 2010 LPG [Member] gal	Sep. 30, 2011 Natural Gas [Member] DTH	Sep. 30, 2010 Natural Gas [Member] DTH	Sep. 30, 2011 Electricity (millions of kilowatt-hours) Call Option [Member] kWh	Sep. 30, 2010 Electricity (millions of kilowatt-hours) Call Option [Member] kWh	Sep. 30, 2011 Electricity (millions of kilowatt-hours) Put Option [Member] kWh	Sep. 30, 2010 Electricity (millions of kilowatt-hours) Put Option [Member] kWh	Sep. 30, 2011 Electric transmission congestion - Electric Utility [Member] kWh	Sep. 30, 2010 Electric transmission congestion - Electric Utility [Member] kWh	Sep. 30, 2011 Electric transmission congestion (excluding Electric Utility) [Member] kWh	Sep. 30, 2010 Electric transmission congestion (excluding Electric Utility) [Member] kWh	Sep. 30, 2011 Net Investment Hedges [Member] EUR (€)	Sep. 30, 2010 Net Investment Hedges [Member] EUR (€)	Sep. 30, 2011 Net Investment Hedges [Member] Foreign Currency [Member] EUR (€)	Sep. 30, 2011 Foreign Currency [Member] USD ($)	Sep. 30, 2010 Foreign Currency [Member] USD ($)	Sep. 30, 2011 Interest Rate Swaps [Member] EUR (€)	Sep. 30, 2010 Interest Rate Swaps [Member] EUR (€)	Sep. 30, 2011 Interest Rate Protection Agreements [Member] USD ($)	Sep. 30, 2010 Interest Rate Protection Agreements [Member] USD ($)	Sep. 30, 2011 Foreign Currency Gain (Loss) [Member] USD ($)
Derivative (Textual) [Abstract]
Notional amount (in units)						15,100,000	19,500,000		788,600,000	990,700,000	4,200,000	4,000,000	138,000,000	160,000,000	26,100,000	36,300,000	1,219,800,000	1,203,800,000	204,900,000	0	208,600,000	546,800,000	1,418,600,000	1,026,400,000
Maximum length of time hedged in price risk cash flow hedges						13 months			32 months				12 months		37 months		22 months		27 months				8 months					30 months
Underlying variable rate debt																									€ 14,500,000	€ 10,000,000	€ 120,000,000	$ 133,900,000	$ 108,600,000	€ 424,200,000	€ 703,200,000	$ 173,000,000	$ 0
Maximum length of time hedged in price risk cash flow hedges																									September 2012
Fair values of electric utility's forward purchase power agreements		91,900,000	91,900,000	91,100,000					8,700,000	19,700,000
AmeriGas OLP's unsecured revolving credit agreement								150,000,000
Maximum period of hedging exposure to variability in cash flows associated with price risk, weighted average													5 months		9 months		7 months		14 months				0 months					11 months
Repayments of Senior Debt		350,000,000
Minimum approximate range of estimated dollar-denominated purchases of LPG																												15.00%
Maximum approximate range of estimated dollar-denominated purchases of LPG																												30.00%
Long term debt not issued		150,000,000	150,000,000
Loss recorded on the contracts																																		6,100,000
Disclosures About Derivative Instruments Hedging Activities (Textual) [Abstract]
Net losses associated with commodity price risk hedges expected to be reclassified into earnings during the next twelve months		32,100,000	32,100,000
Amount of net losses associated with interest rate hedges to be reclassified with interest rate hedges during the next 12 months		1,200,000	1,200,000
Maximum approximate range of estimated dollar-denominated purchases of LPG																												30.00%
Amount of net losses associated with currency rate risk to be reclassified into earnings during the next 12 months		2,500,000	2,500,000
Restricted Cash in brokerage accounts		17,200,000	17,200,000	34,800,000
Loss as a result of the discontinuance of cash flow hedge accounting				12,200,000	1,700,000
Transmission organization controls movements of wholesale electricity in number of states			14
Write off of settled but unamortized interest rate protection agreements included in extinguishment of debt	$ 2.6